v0.4.1

We don't know how to correctly use these identities. In particular, some
identities store parts of their private key material in certificate
extensions to work around hardware limitations. Not understanding these
extensions could lead to encrypting with the wrong protocol and
violating security assumptions.

.github/dependabot.yml

@@ -0,0 +1,12 @@
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: "/"
+    schedule:
+      interval: daily
+      timezone: Etc/UTC
+    open-pull-requests-limit: 10
+    reviewers:
+      - str4d
+    assignees:
+      - str4d

.github/workflows/ci.yml

@@ -22,130 +22,49 @@ jobs:
             os: macos-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
-      - uses: actions-rs/toolchain@v1
-        with:
-          toolchain: 1.51.0
-          override: true
       - name: Install build dependencies
         run: sudo apt install ${{ matrix.build_deps }}
         if: matrix.build_deps != ''
-      - name: cargo fetch
+      - name: Install test dependencies
-        uses: actions-rs/cargo@v1
+        run: cargo install rage
-        with:
+      - run: cargo fetch
-          command: fetch
       - name: Build tests
-        uses: actions-rs/cargo@v1
+        run: cargo build --verbose --tests
-        with:
-          command: build
-          args: --verbose --tests
       - name: Run tests
-        uses: actions-rs/cargo@v1
+        run: cargo test --verbose
-        with:
-          command: test
-          args: --verbose
-
-  clippy:
-    name: Clippy (1.51.0)
-    timeout-minutes: 30
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-      - uses: actions-rs/toolchain@v1
-        with:
-          toolchain: 1.51.0
-          components: clippy
-          override: true
-      - name: Install build dependencies
-        run: sudo apt install libpcsclite-dev
-      - name: Run clippy
-        uses: actions-rs/clippy-check@v1
-        with:
-          name: Clippy (1.51.0)
-          token: ${{ secrets.GITHUB_TOKEN }}
-          args: --all-features --all-targets -- -D warnings
-
-  clippy-nightly:
-    name: Clippy (nightly)
-    timeout-minutes: 30
-    runs-on: ubuntu-latest
-    continue-on-error: true
-    steps:
-      - uses: actions/checkout@v2
-      - uses: actions-rs/toolchain@v1
-        with:
-          toolchain: nightly
-          components: clippy
-          override: true
-      - name: Install build dependencies
-        run: sudo apt install libpcsclite-dev
-      - name: Run Clippy (nightly)
-        uses: actions-rs/clippy-check@v1
-        continue-on-error: true
-        with:
-          name: Clippy (nightly)
-          token: ${{ secrets.GITHUB_TOKEN }}
-          args: --all-features --all-targets
 
   codecov:
     name: Code coverage
     runs-on: ubuntu-latest
-
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
-      # Use stable for this to ensure that cargo-tarpaulin can be built.
-      - uses: actions-rs/toolchain@v1
-        with:
-          toolchain: stable
-          override: true
       - name: Install build dependencies
         run: sudo apt install libpcsclite-dev
+      - name: Install coverage dependencies
+        run: cargo install cargo-tarpaulin
       - name: Generate coverage report
-        uses: actions-rs/tarpaulin@v0.1
+        run: cargo tarpaulin --engine llvm --all-features --release --timeout 600 --out Xml
-        with:
-          args: --release --timeout 180 --out Xml
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v1.0.3
+        uses: codecov/codecov-action@v3.1.1
-        with:
-          token: ${{secrets.CODECOV_TOKEN}}
 
   doc-links:
     name: Intra-doc links
     runs-on: ubuntu-latest
-
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
-      - uses: actions-rs/toolchain@v1
-        with:
-          toolchain: 1.51.0
-          override: true
       - name: Install build dependencies
         run: sudo apt install libpcsclite-dev
-      - name: cargo fetch
+      - run: cargo fetch
-        uses: actions-rs/cargo@v1
+      # Requires #![deny(rustdoc::broken_intra_doc_links)] in crates.
-        with:
-          command: fetch
-
-      # Ensure intra-documentation links all resolve correctly
-      # Requires #![deny(intra_doc_link_resolution_failure)] in crates.
       - name: Check intra-doc links
-        uses: actions-rs/cargo@v1
+        run: cargo doc --document-private-items
-        with:
-          command: doc
-          args: --document-private-items
 
   fmt:
     name: Rustfmt
     timeout-minutes: 30
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
-      - uses: actions-rs/toolchain@v1
+      - name: Check formatting
-        with:
+        run: cargo fmt -- --check
-          toolchain: 1.51.0
-          override: true
-      - run: rustup component add rustfmt
-      - uses: actions-rs/cargo@v1
-        with:
-          command: fmt
-          args: -- --check

.github/workflows/lints-beta.yml

@@ -0,0 +1,23 @@
+name: Beta lints
+
+# We only run these lints on trial-merges of PRs to reduce noise.
+on: pull_request
+
+jobs:
+  clippy-beta:
+    name: Clippy (beta)
+    timeout-minutes: 30
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: dtolnay/rust-toolchain@beta
+        id: toolchain
+      - run: rustup override set ${{steps.toolchain.outputs.name}}
+      - name: Install build dependencies
+        run: sudo apt install libpcsclite-dev
+      - name: Clippy (beta)
+        uses: actions-rs/clippy-check@v1
+        with:
+          name: Clippy (beta)
+          token: ${{ secrets.GITHUB_TOKEN }}
+          args: --all-features --all-targets -- -W clippy::all

.github/workflows/lints-stable.yml

@@ -0,0 +1,20 @@
+name: Stable lints
+
+# We only run these lints on trial-merges of PRs to reduce noise.
+on: pull_request
+
+jobs:
+  clippy:
+    name: Clippy (MSRV)
+    timeout-minutes: 30
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Install build dependencies
+        run: sudo apt install libpcsclite-dev
+      - name: Run clippy
+        uses: actions-rs/clippy-check@v1
+        with:
+          name: Clippy (MSRV)
+          token: ${{ secrets.GITHUB_TOKEN }}
+          args: --all-features --all-targets -- -D warnings

.github/workflows/release.yml

@@ -17,10 +17,14 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        name: [linux, windows, macos]
+        name:
+          - linux
+          - macos-arm64
+          - macos-x86_64
+          - windows
         include:
           - name: linux
-            os: ubuntu-16.04
+            os: ubuntu-18.04
             build_deps: >
               libpcsclite-dev
             archive_name: age-plugin-yubikey.tar.gz
@@ -31,13 +35,20 @@ jobs:
             archive_name: age-plugin-yubikey.zip
             asset_suffix: x86_64-windows.zip
 
-          - name: macos
+          - name: macos-arm64
+            os: macos-latest
+            target: aarch64-apple-darwin
+            build_flags: --target aarch64-apple-darwin
+            archive_name: age-plugin-yubikey.tar.gz
+            asset_suffix: arm64-darwin.tar.gz
+
+          - name: macos-x86_64
             os: macos-latest
             archive_name: age-plugin-yubikey.tar.gz
             asset_suffix: x86_64-darwin.tar.gz
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
           toolchain: stable
@@ -76,12 +87,10 @@ jobs:
         if: matrix.name == 'windows'
 
       - name: Upload archive to release
-        uses: svenstaro/upload-release-action@2.2.0
+        uses: svenstaro/upload-release-action@2.5.0
         with:
-          repo_token: ${{ secrets.GITHUB_TOKEN }}
           file: ${{ matrix.archive_name }}
           asset_name: age-plugin-yubikey-$tag-${{ matrix.asset_suffix }}
-          tag: ${{ github.ref }}
           prerelease: true
         if: github.event.inputs.test != 'true'
 
@@ -98,7 +107,7 @@ jobs:
               libpcsclite-dev
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
           toolchain: stable
@@ -137,11 +146,9 @@ jobs:
           args: --package age-plugin-yubikey --no-build --target ${{ matrix.target }}
 
       - name: Upload Debian package to release
-        uses: svenstaro/upload-release-action@2.2.0
+        uses: svenstaro/upload-release-action@2.5.0
         with:
-          repo_token: ${{ secrets.GITHUB_TOKEN }}
           file: target/${{ matrix.target }}/debian/*.deb
-          tag: ${{ github.ref }}
           file_glob: true
           prerelease: true
         if: github.event.inputs.test != 'true'

CHANGELOG.md

@@ -0,0 +1,92 @@
+# Changelog
+All notable changes to this crate will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to Rust's notion of
+[Semantic Versioning](https://semver.org/spec/v2.0.0.html). All versions prior
+to 0.3.0 are beta releases.
+
+## [Unreleased]
+
+## [0.3.4], [0.4.1] - 2026-04-08
+### Fixed
+- `age-plugin-yubikey` now completely ignores any identity that has unrecognised
+  critical extensions in its certificate, to ensure it doesn't misuse a newer
+  identity type.
+
+## [0.4.0] - 2023-04-09
+### Changed
+- MSRV is now 1.65.0.
+- The YubiKey PIV PIN and touch caches are now preserved across processes in
+  most cases. See [README.md](README.md#agent-support) for exceptions. This has
+  several usability effects (not applicable to YubiKey 4 series):
+  - If a YubiKey's PIN is cached by an agent like `yubikey-agent`, and then
+    `age-plugin-yubikey` is run (either directly or as a plugin), the agent
+    won't request a PIN entry on its next use.
+  - If a YubiKey's PIN was requested by either a previous invocation of
+    `age-plugin-yubikey` or an agent like `yubikey-agent`, subsequent calls to
+    `age-plugin-yubikey` won't request a PIN entry to decrypt a file with an
+    identity that has a PIN policy of `once`.
+
+### Fixed
+- Identities can now be generated with a PIN policy of "always" (in previous
+  versions of `age-plugin-yubikey` this would cause an error).
+
+## [0.3.3] - 2023-02-11
+### Fixed
+- When `age-plugin-yubikey` assists the user in changing their PIN from the
+  default PIN, it no longer tells the user that PINs shorter than 6 characters
+  are allowed, and instead loops until the user enters a PIN of valid length.
+  It also now prevents the user from setting their PIN to the default PIN, to
+  avoid creating a cycle.
+- More kinds of SmartCard readers are ignored when they have no SmartCard
+  inserted.
+
+## [0.3.2] - 2023-01-01
+### Changed
+- The "sharing violation" logic now also sends SIGHUP to any `yubikey-agent`
+  that is running, to have them release any YubiKey locks they are holding.
+
+### Fixed
+- The "sharing violation" logic now runs during plugin mode as intended. In the
+  previous release it only ran during direct `age-plugin-yubikey` usage.
+
+## [0.3.1] - 2022-12-30
+### Changed
+- If a "sharing violation" error is encountered while opening a connection to a
+  YubiKey, and `scdaemon` is running (which can hold exclusive access to a
+  YubiKey indefinitely), `age-plugin-yubikey` now attempts to stop `scdaemon` by
+  interrupting it (or killing it on Windows), and then tries again to open the
+  connection.
+- Several error messages were enhanced with guidance on how to resolve their
+  respective issue.
+
+## [0.3.0] - 2022-05-02
+First non-beta release!
+
+### Changed
+- MSRV is now 1.56.0.
+- During decryption, when asked to insert a YubiKey, you can now choose to skip
+  it, allowing the client to move on to the next identity instead of returning
+  an error.
+- Certain kinds of PIN invalidity will now cause the plugin to re-request the
+  PIN instead of aborting: if the PIN is too short or too long, or if the user
+  touched the YubiKey early and "typed" an OTP.
+
+### Fixed
+- The "default" identity (provided by clients that invoke `age-plugin-yubikey`
+  using `-j yubikey`) previously caused a panic. It is now correctly treated as
+  an invalid identity (because this plugin does not support default identities).
+
+## [0.2.0] - 2021-11-22
+### Fixed
+- Attempts-before-blocked counter is now returned as part of the invalid PIN
+  error string.
+- PIN is no longer requested when fetching the recipient for a slot, or when
+  decrypting with a slot that has a PIN policy of Never.
+- Migrated to `yubikey 0.5` to fix `cargo install age-plugin-yubikey` error
+  (caused by the `yubikey-piv` crate being yanked after it was renamed).
+
+## [0.1.0] - 2021-05-02
+
+Initial beta release.

Cargo.toml

@@ -1,19 +1,19 @@
 [package]
 name = "age-plugin-yubikey"
-description = "[BETA] YubiKey plugin for age clients"
+description = "YubiKey plugin for age clients"
-version = "0.1.0"
+version = "0.4.1"
 authors = ["Jack Grigg <thestr4d@gmail.com>"]
 repository = "https://github.com/str4d/age-plugin-yubikey"
 readme = "README.md"
 keywords = ["age", "cli", "encryption", "yubikey"]
 categories = ["command-line-utilities", "cryptography"]
 license = "MIT OR Apache-2.0"
-edition = "2018"
+edition = "2021"
+rust-version = "1.65" # MSRV
 
 [package.metadata.deb]
 extended-description = """\
-An age plugin adding support for YubiKeys and other PIV hardware tokens. \
+An age plugin adding support for YubiKeys and other PIV hardware tokens."""
-Currently in BETA; we strongly recommend using this with a new YubiKey."""
 section = "utils"
 assets = [
     ["target/release/age-plugin-yubikey", "usr/bin/", "755"],
@@ -22,26 +22,37 @@ assets = [
 ]
 
 [dependencies]
-age-core = "0.6"
+age-core = "0.9"
-age-plugin = "0.1"
+age-plugin = "0.4"
-base64 = "0.13"
+base64 = "0.21"
-bech32 = "0.8"
+bech32 = "0.9"
-console = "0.14"
+console = { version = "0.15", default-features = false }
-dialoguer = "0.8"
+dialoguer = { version = "0.10", default-features = false, features = ["password"] }
-env_logger = "0.8"
+env_logger = "0.10"
 gumdrop = "0.8"
 hex = "0.4"
 log = "0.4"
-p256 = { version = "0.7", features = ["ecdh"] }
+p256 = { version = "0.13", features = ["ecdh"] }
 pcsc = "2.4"
-rand = "0.7"
+rand = "0.8"
-secrecy = "0.7"
+sha2 = "0.10"
-sha2 = "0.9"
 which = "4.1"
 x509 = "0.2"
-x509-parser = "0.9"
+x509-parser = "0.14"
-yubikey-piv = { version = "0.3", features = ["untested"] }
+yubikey = { version = "=0.8.0-pre.0", features = ["untested"] }
+
+# Translations
+i18n-embed = { version = "0.13", features = ["desktop-requester", "fluent-system"] }
+i18n-embed-fl = "0.6"
+lazy_static = "1"
+rust-embed = "6"
+
+# GnuPG coexistence
+sysinfo = "0.28"
 
 [dev-dependencies]
 flate2 = "1"
 man = "0.3"
+tempfile = "3"
+test-with = "0.9"
+which = "4"

README.md

@@ -4,23 +4,37 @@
 like [`age`](https://age-encryption.org) and [`rage`](https://str4d.xyz/rage),
 which enables files to be encrypted to age identities stored on YubiKeys.
 
-This plugin is in **BETA**; we strongly recommend using this with a new YubiKey,
-or one that you do not care about.
-
 ## Installation
 
+| Environment | CLI command |
+|-------------|-------------|
+| Cargo (Rust 1.65+) | `cargo install age-plugin-yubikey` |
+| Homebrew (macOS or Linux) | `brew install age-plugin-yubikey` |
+
 On Windows, Linux, and macOS, you can use the
 [pre-built binaries](https://github.com/str4d/age-plugin-yubikey/releases).
 
-If your system has Rust 1.51+ installed (either via `rustup` or a system
-package), you can build directly from source:
-
-```
-cargo install age-plugin-yubikey
-```
-
 Help from new packagers is very welcome.
 
+### Linux, BSD, etc.
+
+On non-Windows, non-macOS systems, you need to ensure that the `pcscd` service
+is installed and running. 
+
+| Environment | CLI command |
+|-------------|-------------|
+| Debian or Ubuntu | `sudo apt-get install pcscd` |
+| OpenBSD | As ```root``` do:<br>`pkg_add pcsc-lite ccid`<br>`rcctl enable pcscd`<br>`rcctl start pcscd` |
+| FreeBSD | As ```root``` do:<br>`pkg install pcsc-lite libccid`<br>`service pcscd enable`<br>`service pcscd start` |
+
+When installing via Cargo, you also need to ensure that the development headers
+for the `pcsc-lite` library are available, so that the `pcsc-sys` crate can be
+compiled.
+
+| Environment | CLI command |
+|-------------|-------------|
+| Debian or Ubuntu | `sudo apt-get install libpcsclite-dev` |
+
 ### Windows Subsystem for Linux (WSL)
 
 WSL does not currently provide native support for USB devices. However, Windows
@@ -38,7 +52,12 @@ YubiKey:
 
 ## Configuration
 
-There are two ways to configure a YubiKey as an `age` identity. You can run the
+`age-plugin-yubikey` identities have two parts:
+- The secret key material, which is stored inside a YubiKey.
+- An age identity file, which contains information that an age client can use to
+  figure out which YubiKey secret key should be used.
+
+There are two ways to configure a YubiKey as an age identity. You can run the
 plugin binary directly to use a simple text interface, which will create an age
 identity file:
 
@@ -64,6 +83,14 @@ Once an identity has been created, you can regenerate it later:
 $ age-plugin-yubikey --identity [--serial SERIAL] --slot SLOT
 ```
 
+To use the identity with an age client, it needs to be stored in a file. When
+using the above programmatic flags, you can do this by redirecting standard
+output to a file. On a Unix system like macOS or Ubuntu:
+
+```
+$ age-plugin-yubikey --identity --slot SLOT > yubikey-identity.txt
+```
+
 ## Usage
 
 The age recipients contained in all connected YubiKeys can be printed on
@@ -88,18 +115,39 @@ age client as normal (e.g. `rage -d -i yubikey-identity.txt`).
 ### Agent support
 
 `age-plugin-yubikey` does not provide or interact with an agent for decryption.
-As age plugin binaries have short lifetimes (they only run while the age client
+It does however attempt to preserve the PIN cache by not soft-resetting the
-is running), this means that YubiKey identities configured with a PIN policy of
+YubiKey after a decryption or read-only operation, which enables YubiKey
-`once` will actually prompt for the PIN on every decryption.
+identities configured with a PIN policy of `once` to not prompt for the PIN on
+every decryption. **This does not work for YubiKey 4 series.**
 
-A decryption agent will most likely be implemented as a separate age plugin that
+The session that corresponds to the `once` policy can be ended in several ways,
-interacts with [`yubikey-agent`](https://github.com/FiloSottile/yubikey-agent),
+not all of which are necessarily intuitive:
-enabling YubiKeys to be used simultaneously with age and SSH.
+
+- Unplugging the YubiKey (the obvious way).
+- Using a different applet (e.g. FIDO2). This causes the PIV applet to be closed
+  which clears its state.
+  - This is why the YubiKey 4 series does not support PIN cache preservation:
+    their serial can only be obtained by switching to the OTP applet.
+- Generating a new age identity via `age-plugin-yubikey --generate` or the CLI
+  interface. This is to avoid leaving the YubiKey authenticated with the
+  management key.
+
+If the current PIN UX proves to be insufficient, a decryption agent will most
+likely be implemented as a separate age plugin that interacts with
+[`yubikey-agent`](https://github.com/FiloSottile/yubikey-agent), enabling
+YubiKeys to be used simultaneously with age and SSH.
 
 ### Manual setup and technical details
 
-`age-plugin-yubikey` only officially supports YubiKeys set up either via the
+`age-plugin-yubikey` only officially supports the following YubiKey variants,
-text interface or the `--generate` flag.
+set up either via the text interface or the `--generate` flag:
+
+- YubiKey 4 series
+- YubiKey 5 series
+
+NOTE: Nano and USB-C variants of the above are also supported. The pre-YK4
+YubiKey NEO series is **NOT** supported. The blue "Security Key by Yubico" will
+also not work (as it doesn't support PIV).
 
 In practice, any PIV token with an ECDSA P-256 key and certificate in one of the
 20 "retired" slots should work. You can list all age-compatible keys with:

i18n.toml

@@ -0,0 +1,4 @@
+fallback_language = "en-US"
+
+[fluent]
+assets_dir = "i18n"

i18n/en-US/age_plugin_yubikey.ftl

@@ -0,0 +1,251 @@
+# Copyright 2022 Jack Grigg
+#
+# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+# option. This file may not be copied, modified, or distributed
+# except according to those terms.
+
+### Localization for strings in age-plugin-yubikey
+
+-age = age
+-yubikey = YubiKey
+-yubikeys = YubiKeys
+-age-plugin-yubikey = age-plugin-yubikey
+-pcscd = pcscd
+
+## CLI commands and flags
+
+-cmd-generate = --generate
+-cmd-identity = --identity
+-cmd-list     = --list
+-cmd-list-all = --list-all
+
+-flag-force  = --force
+-flag-serial = --serial
+-flag-slot   = --slot
+
+## YubiKey metadata
+
+pin-policy-always = Always (A PIN is required for every decryption, if set)
+pin-policy-once   = Once   (A PIN is required once per session, if set)
+pin-policy-never  = Never  (A PIN is NOT required to decrypt)
+
+touch-policy-always = Always (A physical touch is required for every decryption)
+touch-policy-cached = Cached (A physical touch is required for decryption, and is cached for 15 seconds)
+touch-policy-never  = Never  (A physical touch is NOT required to decrypt)
+
+unknown-policy = Unknown
+
+yubikey-metadata =
+    #       Serial: {$serial}, Slot: {$slot}
+    #         Name: {$name}
+    #      Created: {$created}
+    #   PIN policy: {$pin_policy}
+    # Touch policy: {$touch_policy}
+yubikey-identity =
+    {$yubikey_metadata}
+    #    Recipient: {$recipient}
+    {$identity}
+
+## CLI setup via text interface
+
+cli-setup-intro =
+    ✨ Let's get your {-yubikey} set up for {-age}! ✨
+
+    This tool can create a new {-age} identity in a free slot of your {-yubikey}.
+    It will generate an identity file that you can use with an {-age} client,
+    along with the corresponding recipient. You can also do this directly
+    with:
+    {"    "}{$generate_usage}
+
+    If you are already using a {-yubikey} with {-age}, you can select an existing
+    slot to recreate its corresponding identity file and recipient.
+
+    When asked below to select an option, use the up/down arrow keys to
+    make your choice, or press [Esc] or [q] to quit.
+
+cli-setup-insert-yk           = ⏳ Please insert the {-yubikey} you want to set up.
+cli-setup-yk-name             = {$yubikey_name} (Serial: {$yubikey_serial})
+cli-setup-select-yk           = 🔑 Select a {-yubikey}
+cli-setup-slot-usable         = Slot {$slot_index} ({$slot_name})
+cli-setup-slot-unusable       = Slot {$slot_index} (Unusable)
+cli-setup-slot-empty          = Slot {$slot_index} (Empty)
+cli-setup-select-slot         = 🕳️  Select a slot for your {-age} identity
+cli-setup-name-identity       = 📛 Name this identity
+cli-setup-select-pin-policy   = 🔤 Select a PIN policy
+cli-setup-select-touch-policy = 👆 Select a touch policy
+
+cli-setup-yk4-pin-policy =
+    ⚠️ Your {-yubikey} is a {-yubikey} 4 series. With ephemeral applications like
+    {-age-plugin-yubikey}, a PIN policy of "Once" behaves like a PIN policy of
+    "Always", and your PIN will be requested for every decryption. However, you
+    might still benefit from a PIN policy of "Once" in long-running applications
+    like agents.
+cli-setup-yk4-pin-policy-confirm = Use PIN policy of "Once" with {-yubikey} 4?
+
+cli-setup-generate-new = Generate new identity in slot {$slot_index}?
+cli-setup-use-existing = Use existing identity in slot {$slot_index}?
+
+cli-setup-identity-file-name   = 📝 File name to write this identity to
+cli-setup-identity-file-exists = File exists. Overwrite it?
+
+cli-setup-finished =
+    ✅ Done! This {-yubikey} identity is ready to go.
+
+    🔑 { $is_new ->
+        [true] Here's your shiny new {-yubikey} recipient:
+       *[false] Here's the corresponding {-yubikey} recipient:
+    }
+    {"  "}{$recipient}
+
+    Here are some example things you can do with it:
+
+    - Encrypt a file to this identity:
+    {"  "}{$encrypt_usage}
+
+    - Decrypt a file with this identity:
+    {"  "}{$decrypt_usage}
+
+    - Recreate the identity file:
+    {"  "}{$identity_usage}
+
+    - Recreate the recipient:
+    {"  "}{$recipient_usage}
+
+    💭 Remember: everything breaks, have a backup plan for when this {-yubikey} does.
+
+## Programmatic usage
+
+open-yk-with-serial    = ⏳ Please insert the {-yubikey} with serial {$yubikey_serial}.
+open-yk-without-serial = ⏳ Please insert the {-yubikey}.
+warn-yk-not-connected  = Ignoring {$yubikey_name}: not connected
+warn-yk-missing-applet = Ignoring {$yubikey_name}: Missing {$applet_name} applet
+
+print-recipient = Recipient: {$recipient}
+
+printed-kind-identities = identities
+printed-kind-recipients = recipients
+printed-multiple = Generated {$kind} for {$count} slots. If you intended to select a slot, use {-flag-slot}.
+
+## YubiKey management
+
+mgr-enter-pin = Enter PIN for {-yubikey} with serial {$yubikey_serial} (default is {$default_pin})
+
+mgr-change-default-pin =
+    ✨ Your {-yubikey} is using the default PIN. Let's change it!
+    ✨ We'll also set the PUK equal to the PIN.
+
+    🔐 The PIN can be numbers, letters, or symbols. Not just numbers!
+    📏 The PIN must be at least 6 and at most 8 characters in length.
+    ❌ Your keys will be lost if the PIN and PUK are locked after 3 incorrect tries.
+
+mgr-enter-current-puk = Enter current PUK (default is {$default_puk})
+mgr-choose-new-pin    = Choose a new PIN/PUK
+mgr-repeat-new-pin    = Repeat the PIN/PUK
+mgr-pin-mismatch      = PINs don't match
+mgr-nope-default-pin  = You entered the default PIN again. You need to change it.
+
+mgr-changing-mgmt-key =
+    ✨ Your {-yubikey} is using the default management key.
+    ✨ We'll migrate it to a PIN-protected management key.
+mgr-changing-mgmt-key-error =
+    An error occurred while setting the new management key.
+    ⚠️ SAVE THIS MANAGEMENT KEY - YOU MAY NEED IT TO MANAGE YOUR {-yubikey}! ⚠️
+    {"  "}{$management_key}
+mgr-changing-mgmt-key-success = Success!
+
+## YubiKey keygen
+
+builder-gen-key  = 🎲 Generating key...
+builder-gen-cert = 🔏 Generating certificate...
+builder-touch-yk = 👆 Please touch the {-yubikey}
+
+## Plugin usage
+
+plugin-err-invalid-recipient = Invalid recipient
+plugin-err-invalid-identity  = Invalid {-yubikey} stub
+plugin-err-invalid-stanza    = Invalid {-yubikey} stanza
+plugin-err-decryption-failed = Failed to decrypt {-yubikey} stanza
+
+plugin-insert-yk            = Please insert {-yubikey} with serial {$yubikey_serial}
+plugin-yk-is-plugged-in     = {-yubikey} is plugged in
+plugin-skip-this-yk         = Skip this {-yubikey}
+plugin-insert-yk-retry      = Could not open {-yubikey}. Please insert {-yubikey} with serial {$yubikey_serial}
+plugin-err-yk-not-found     = Could not find {-yubikey} with serial {$yubikey_serial}
+plugin-err-yk-opening       = Could not open {-yubikey} with serial {$yubikey_serial}
+plugin-err-yk-timed-out     = Timed out while waiting for {-yubikey} with serial {$yubikey_serial} to be inserted
+plugin-err-yk-stub-mismatch = A {-yubikey} stub did not match the {-yubikey}
+
+plugin-err-yk-invalid-pin-policy = Certificate for {-yubikey} identity contains an invalid PIN policy
+
+plugin-enter-pin            = Enter PIN for {-yubikey} with serial {$yubikey_serial}
+plugin-err-accidental-touch = Did you touch the {-yubikey} by accident?
+plugin-err-pin-too-short    = PIN was too short.
+plugin-err-pin-too-long     = PIN was too long.
+plugin-err-pin-required     = A PIN is required for {-yubikey} with serial {$yubikey_serial}
+
+## Errors
+
+err-mgmt-key-auth = Failed to authenticate with the PIN-protected management key.
+rec-mgmt-key-auth =
+    Check whether your management key is using the TDES algorithm.
+    AES is not supported yet: {$aes_url}
+err-custom-mgmt-key = Custom unprotected non-TDES management keys are not supported.
+rec-change-mgmt-key =
+    You can use the {-yubikey} Manager CLI to change to a protected management key:
+    {"  "}{$cmd}
+
+    See here for more information about {-yubikey} Manager:
+    {"  "}{$url}
+
+err-invalid-flag-command = Flag '{$flag}' cannot be used with '{$command}'.
+err-invalid-flag-tui     = Flag '{$flag}' cannot be used with the interactive interface.
+err-invalid-pin-policy   = Invalid PIN policy '{$policy}' (expected [{$expected}]).
+err-invalid-slot         = Invalid slot '{$slot}' (expected number between 1 and 20).
+err-invalid-touch-policy = Invalid touch policy '{$policy}' (expected [{$expected}]).
+err-io                   = Failed to set up {-yubikey}: {$err}
+err-multiple-commands    = Only one of {-cmd-generate}, {-cmd-identity}, {-cmd-list}, {-cmd-list-all} can be specified.
+err-multiple-yubikeys    = Multiple {-yubikeys} are plugged in. Use {-flag-serial} to select a single {-yubikey}.
+err-no-empty-slots       = {-yubikey} with serial {$serial} has no empty slots.
+err-no-matching-serial   = Could not find {-yubikey} with serial {$serial}.
+err-slot-has-no-identity = Slot {$slot} does not contain an {-age} identity or compatible key.
+err-slot-is-not-empty    = Slot {$slot} is not empty. Use {-flag-force} to overwrite the slot.
+err-timed-out            = Timed out while waiting for a {-yubikey} to be inserted.
+err-use-list-for-single  = Use {-cmd-list} to print the recipient for a single slot.
+
+err-yk-no-service-macos = The Crypto Token Kit service is not running.
+rec-yk-no-service-macos =
+    You may need to restart it. See this Stack Exchange answer for more help:
+    {"  "}{$url}
+
+err-yk-no-service-pcscd = {-pcscd} is not running.
+rec-yk-no-service-pcscd =
+    If you are on Debian or Ubuntu, you can install it with:
+    {"  "}{$apt}
+
+rec-yk-no-service-pcscd-bsd =
+    You can install and run it as root with:
+    {"  "}{$pkg}
+    {"  "}{$service_enable}
+    {"  "}{$service_start}
+
+err-yk-no-service-win = The Smart Cards for Windows service is not running.
+rec-yk-no-service-win =
+    See this troubleshooting guide for more help:
+    {"  "}{$url}
+
+err-yk-not-found         = Please insert the {-yubikey} you want to set up
+err-yk-general           = Error while communicating with {-yubikey}: {$err}
+err-yk-general-cause     = Cause: {$inner_err}
+
+err-yk-wrong-pin = Invalid {$pin_kind} ({$tries ->
+    [one] {$tries} try remaining
+   *[other] {$tries} tries remaining
+} before it is blocked)
+err-yk-pin-locked = {$pin_kind} locked
+
+err-ux-A = Did this not do what you expected? Could an error be more useful?
+err-ux-B = Tell us
+# Put (len(A) - len(B) - 46) spaces here.
+err-ux-C = {"            "}

rust-toolchain.toml

@@ -0,0 +1,3 @@
+[toolchain]
+channel = "1.65.0"
+components = ["clippy", "rustfmt"]

src/builder.rs

@@ -1,17 +1,18 @@
+use dialoguer::Password;
 use rand::{rngs::OsRng, RngCore};
 use x509::RelativeDistinguishedName;
-use yubikey_piv::{
+use yubikey::{
-    certificate::{Certificate, PublicKeyInfo},
+    certificate::Certificate,
-    key::{generate as yubikey_generate, AlgorithmId, RetiredSlotId, SlotId},
+    piv::{generate as yubikey_generate, AlgorithmId, RetiredSlotId, SlotId},
-    policy::{PinPolicy, TouchPolicy},
+    Key, PinPolicy, TouchPolicy, YubiKey,
-    Key, YubiKey,
 };
 
 use crate::{
     error::Error,
+    fl,
+    key::{self, Stub},
     p256::Recipient,
     util::{Metadata, POLICY_EXTENSION_OID},
-    yubikey::{self, Stub},
     BINARY_NAME, USABLE_SLOTS,
 };
 
@@ -87,16 +88,12 @@ impl IdentityBuilder {
         let pin_policy = self.pin_policy.unwrap_or(DEFAULT_PIN_POLICY);
         let touch_policy = self.touch_policy.unwrap_or(DEFAULT_TOUCH_POLICY);
 
+        eprintln!("{}", fl!("builder-gen-key"));
+
         // No need to ask for users to enter their PIN if the PIN policy requires it,
         // because here we _always_ require them to enter their PIN in order to access the
         // protected management key (which is necessary in order to generate identities).
-        yubikey::manage(yubikey)?;
+        key::manage(yubikey)?;
-
-        if let TouchPolicy::Never = touch_policy {
-            // No need to touch YubiKey
-        } else {
-            eprintln!("👆 Please touch the YubiKey");
-        }
 
         // Generate a new key in the selected slot.
         let generated = yubikey_generate(
@@ -107,14 +104,12 @@ impl IdentityBuilder {
             touch_policy,
         )?;
 
-        let recipient = match &generated {
+        let recipient = Recipient::from_spki(&generated).expect("YubiKey generates a valid pubkey");
-            PublicKeyInfo::EcP256(pubkey) => {
-                Recipient::from_encoded(pubkey).expect("YubiKey generates a valid pubkey")
-            }
-            _ => unreachable!(),
-        };
         let stub = Stub::new(yubikey.serial(), slot, &recipient);
 
+        eprintln!();
+        eprintln!("{}", fl!("builder-gen-cert"));
+
         // Pick a random serial for the new self-signed certificate.
         let mut serial = [0; 20];
         OsRng.fill_bytes(&mut serial);
@@ -123,6 +118,23 @@ impl IdentityBuilder {
             .name
             .unwrap_or(format!("age identity {}", hex::encode(stub.tag)));
 
+        if let PinPolicy::Always = pin_policy {
+            // We need to enter the PIN again.
+            let pin = Password::new()
+                .with_prompt(fl!(
+                    "plugin-enter-pin",
+                    yubikey_serial = yubikey.serial().to_string(),
+                ))
+                .report(true)
+                .interact()?;
+            yubikey.verify_pin(pin.as_bytes())?;
+        }
+        if let TouchPolicy::Never = touch_policy {
+            // No need to touch YubiKey
+        } else {
+            eprintln!("{}", fl!("builder-touch-yk"));
+        }
+
         let cert = Certificate::generate_self_signed(
             yubikey,
             SlotId::Retired(slot),
@@ -140,7 +152,6 @@ impl IdentityBuilder {
             )],
         )?;
 
-        let (_, cert) = x509_parser::parse_x509_certificate(cert.as_ref()).unwrap();
         let metadata = Metadata::extract(yubikey, slot, &cert, false).unwrap();
 
         Ok((

src/error.rs

@@ -1,27 +1,38 @@
 use std::fmt;
 use std::io;
-use yubikey_piv::{key::RetiredSlotId, Serial};
+use yubikey::{piv::RetiredSlotId, Serial};
 
 use crate::util::slot_to_ui;
 
+macro_rules! wlnfl {
+    ($f:ident, $message_id:literal) => {
+        writeln!($f, "{}", $crate::fl!($message_id))
+    };
+    ($f:ident, $message_id:literal, $($kwarg:expr),* $(,)*) => {{
+        writeln!($f, "{}", $crate::fl!($message_id, $($kwarg,)*))
+    }};
+}
+
 pub enum Error {
     CustomManagementKey,
     InvalidFlagCommand(String, String),
     InvalidFlagTui(String),
-    InvalidPinLength,
     InvalidPinPolicy(String),
     InvalidSlot(u8),
     InvalidTouchPolicy(String),
     Io(io::Error),
+    ManagementKeyAuth,
     MultipleCommands,
     MultipleYubiKeys,
     NoEmptySlots(Serial),
     NoMatchingSerial(Serial),
+    PukLocked,
     SlotHasNoIdentity(RetiredSlotId),
     SlotIsNotEmpty(RetiredSlotId),
     TimedOut,
     UseListForSingleSlot,
-    YubiKey(yubikey_piv::Error),
+    WrongPuk(u8),
+    YubiKey(yubikey::Error),
 }
 
 impl From<io::Error> for Error {
@@ -30,8 +41,8 @@ impl From<io::Error> for Error {
     }
 }
 
-impl From<yubikey_piv::error::Error> for Error {
+impl From<yubikey::Error> for Error {
-    fn from(e: yubikey_piv::error::Error) -> Self {
+    fn from(e: yubikey::Error) -> Self {
         Error::YubiKey(e)
     }
 }
@@ -40,91 +51,135 @@ impl From<yubikey_piv::error::Error> for Error {
 // manually to provide the error output we want.
 impl fmt::Debug for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        const CHANGE_MGMT_KEY_CMD: &str =
+            "ykman piv access change-management-key -a TDES --protect";
+        const CHANGE_MGMT_KEY_URL: &str = "https://developers.yubico.com/yubikey-manager/";
+
         match self {
             Error::CustomManagementKey => {
-                writeln!(f, "Custom unprotected management keys are not supported.")?
+                wlnfl!(f, "err-custom-mgmt-key")?;
+                wlnfl!(
+                    f,
+                    "rec-change-mgmt-key",
+                    cmd = CHANGE_MGMT_KEY_CMD,
+                    url = CHANGE_MGMT_KEY_URL
+                )?;
             }
-            Error::InvalidFlagCommand(flag, command) => {
+            Error::InvalidFlagCommand(flag, command) => wlnfl!(
-                writeln!(f, "Flag '{}' cannot be used with '{}'.", flag, command)?
+                f,
+                "err-invalid-flag-command",
+                flag = flag.as_str(),
+                command = command.as_str(),
+            )?,
+            Error::InvalidFlagTui(flag) => wlnfl!(f, "err-invalid-flag-tui", flag = flag.as_str())?,
+            Error::InvalidPinPolicy(s) => wlnfl!(
+                f,
+                "err-invalid-pin-policy",
+                policy = s.as_str(),
+                expected = "always, once, never",
+            )?,
+            Error::InvalidSlot(slot) => wlnfl!(f, "err-invalid-slot", slot = slot)?,
+            Error::InvalidTouchPolicy(s) => wlnfl!(
+                f,
+                "err-invalid-touch-policy",
+                policy = s.as_str(),
+                expected = "always, cached, never",
+            )?,
+            Error::Io(e) => wlnfl!(f, "err-io", err = e.to_string())?,
+            Error::ManagementKeyAuth => {
+                let aes_url = "https://github.com/str4d/age-plugin-yubikey/issues/92";
+                wlnfl!(f, "err-mgmt-key-auth")?;
+                wlnfl!(f, "rec-mgmt-key-auth", aes_url = aes_url)?;
+                wlnfl!(
+                    f,
+                    "rec-change-mgmt-key",
+                    cmd = CHANGE_MGMT_KEY_CMD,
+                    url = CHANGE_MGMT_KEY_URL
+                )?;
             }
-            Error::InvalidFlagTui(flag) => writeln!(
+            Error::MultipleCommands => wlnfl!(f, "err-multiple-commands")?,
-                f,
+            Error::MultipleYubiKeys => wlnfl!(f, "err-multiple-yubikeys")?,
-                "Flag '{}' cannot be used with the interactive interface.",
-                flag
-            )?,
-            Error::InvalidPinLength => writeln!(f, "The PIN needs to be 1-8 characters.")?,
-            Error::InvalidPinPolicy(s) => writeln!(
-                f,
-                "Invalid PIN policy '{}' (expected [always, once, never]).",
-                s
-            )?,
-            Error::InvalidSlot(slot) => writeln!(
-                f,
-                "Invalid slot '{}' (expected number between 1 and 20).",
-                slot
-            )?,
-            Error::InvalidTouchPolicy(s) => writeln!(
-                f,
-                "Invalid touch policy '{}' (expected [always, cached, never]).",
-                s
-            )?,
-            Error::Io(e) => writeln!(f, "Failed to set up YubiKey: {}", e)?,
-            Error::MultipleCommands => writeln!(
-                f,
-                "Only one of --generate, --identity, --list, --list-all can be specified."
-            )?,
-            Error::MultipleYubiKeys => writeln!(
-                f,
-                "Multiple YubiKeys are plugged in. Use --serial to select a single YubiKey."
-            )?,
             Error::NoEmptySlots(serial) => {
-                writeln!(f, "YubiKey with serial {} has no empty slots.", serial)?
+                wlnfl!(f, "err-no-empty-slots", serial = serial.to_string())?
             }
             Error::NoMatchingSerial(serial) => {
-                writeln!(f, "Could not find YubiKey with serial {}.", serial)?
+                wlnfl!(f, "err-no-matching-serial", serial = serial.to_string())?
             }
-            Error::SlotHasNoIdentity(slot) => writeln!(
+            Error::PukLocked => wlnfl!(f, "err-yk-pin-locked", pin_kind = "PUK")?,
-                f,
+            Error::SlotHasNoIdentity(slot) => {
-                "Slot {} does not contain an age identity or compatible key.",
+                wlnfl!(f, "err-slot-has-no-identity", slot = slot_to_ui(slot))?
-                slot_to_ui(slot)
-            )?,
-            Error::SlotIsNotEmpty(slot) => writeln!(
-                f,
-                "Slot {} is not empty. Use --force to overwrite the slot.",
-                slot_to_ui(slot)
-            )?,
-            Error::TimedOut => {
-                writeln!(f, "Timed out while waiting for a YubiKey to be inserted.")?
             }
-            Error::UseListForSingleSlot => {
+            Error::SlotIsNotEmpty(slot) => {
-                writeln!(f, "Use --list to print the recipient for a single slot.")?
+                wlnfl!(f, "err-slot-is-not-empty", slot = slot_to_ui(slot))?
+            }
+            Error::TimedOut => wlnfl!(f, "err-timed-out")?,
+            Error::UseListForSingleSlot => wlnfl!(f, "err-use-list-for-single")?,
+            Error::WrongPuk(tries) => {
+                wlnfl!(f, "err-yk-wrong-pin", pin_kind = "PUK", tries = tries)?
             }
             Error::YubiKey(e) => match e {
-                yubikey_piv::error::Error::NotFound => {
+                yubikey::Error::NotFound => wlnfl!(f, "err-yk-not-found")?,
-                    writeln!(f, "Please insert the YubiKey you want to set up")?
+                yubikey::Error::PcscError {
-                }
+                    inner: Some(pcsc::Error::NoService),
-                yubikey_piv::error::Error::WrongPin { tries } => writeln!(
+                } => {
+                    if cfg!(windows) {
+                        wlnfl!(f, "err-yk-no-service-win")?;
+                        let url = "https://learn.microsoft.com/en-us/windows/security/identity-protection/smart-cards/smart-card-debugging-information#smart-card-service";
+                        wlnfl!(f, "rec-yk-no-service-win", url = url)?;
+                    } else if cfg!(target_os = "macos") {
+                        wlnfl!(f, "err-yk-no-service-macos")?;
+                        let url = "https://apple.stackexchange.com/a/438198";
+                        wlnfl!(f, "rec-yk-no-service-macos", url = url)?;
+                    } else if cfg!(target_os = "openbsd") {
+                        wlnfl!(f, "err-yk-no-service-pcscd")?;
+                        let pkg = "pkg_add pcsc-lite ccid";
+                        let service_enable = "rcctl enable pcscd";
+                        let service_start = "rcctl start pcscd";
+                        wlnfl!(
                             f,
-                    "Invalid PIN ({} tries remaining before it is blocked)",
+                            "rec-yk-no-service-pcscd-bsd",
-                    tries
+                            pkg = pkg,
-                )?,
+                            service_enable = service_enable,
+                            service_start = service_start
+                        )?;
+                    } else if cfg!(target_os = "freebsd") {
+                        wlnfl!(f, "err-yk-no-service-pcscd")?;
+                        let pkg = "pkg install pcsc-lite libccid";
+                        let service_enable = "service pcscd enable";
+                        let service_start = "service pcscd start";
+                        wlnfl!(
+                            f,
+                            "rec-yk-no-service-pcscd-bsd",
+                            pkg = pkg,
+                            service_enable = service_enable,
+                            service_start = service_start
+                        )?;
+                    } else {
+                        wlnfl!(f, "err-yk-no-service-pcscd")?;
+                        let apt = "sudo apt-get install pcscd";
+                        wlnfl!(f, "rec-yk-no-service-pcscd", apt = apt)?;
+                    }
+                }
+                yubikey::Error::PinLocked => wlnfl!(f, "err-yk-pin-locked", pin_kind = "PIN")?,
+                yubikey::Error::WrongPin { tries } => {
+                    wlnfl!(f, "err-yk-wrong-pin", pin_kind = "PIN", tries = tries)?
+                }
                 e => {
-                    writeln!(f, "Error while communicating with YubiKey: {}", e)?;
+                    wlnfl!(f, "err-yk-general", err = e.to_string())?;
                     use std::error::Error;
                     if let Some(inner) = e.source() {
-                        writeln!(f, "Cause: {}", inner)?;
+                        wlnfl!(f, "err-yk-general-cause", inner_err = inner.to_string())?;
                     }
                 }
             },
         }
         writeln!(f)?;
-        writeln!(
+        writeln!(f, "[ {} ]", crate::fl!("err-ux-A"))?;
-            f,
-            "[ Did this not do what you expected? Could an error be more useful? ]"
-        )?;
         write!(
             f,
-            "[ Tell us: https://str4d.xyz/age-plugin-yubikey/report              ]"
+            "[ {}: https://str4d.xyz/age-plugin-yubikey/report {} ]",
+            crate::fl!("err-ux-B"),
+            crate::fl!("err-ux-C")
         )
     }
 }

src/format.rs

@@ -1,11 +1,15 @@
 use age_core::{
     format::{FileKey, Stanza},
-    primitives::{aead_encrypt, hkdf},
+    primitives::aead_encrypt,
+    secrecy::ExposeSecret,
+};
+use base64::{prelude::BASE64_STANDARD_NO_PAD, Engine};
+use p256::{
+    ecdh::EphemeralSecret,
+    elliptic_curve::sec1::{FromEncodedPoint, ToEncodedPoint},
 };
-use p256::{ecdh::EphemeralSecret, elliptic_curve::sec1::ToEncodedPoint};
 use rand::rngs::OsRng;
-use secrecy::ExposeSecret;
+use sha2::Sha256;
-use std::convert::TryInto;
 
 use crate::{p256::Recipient, STANZA_TAG};
 
@@ -23,8 +27,12 @@ pub(crate) struct EphemeralKeyBytes(p256::EncodedPoint);
 
 impl EphemeralKeyBytes {
     fn from_bytes(bytes: [u8; EPK_BYTES]) -> Option<Self> {
-        let encoded = p256::EncodedPoint::from_bytes(&bytes).ok()?;
+        let encoded = p256::EncodedPoint::from_bytes(bytes).ok()?;
-        if encoded.is_compressed() && encoded.decompress().is_some() {
+        if encoded.is_compressed()
+            && p256::PublicKey::from_encoded_point(&encoded)
+                .is_some()
+                .into()
+        {
             Some(EphemeralKeyBytes(encoded))
         } else {
             None
@@ -40,9 +48,9 @@ impl EphemeralKeyBytes {
     }
 
     pub(crate) fn decompress(&self) -> p256::EncodedPoint {
-        self.0
+        // EphemeralKeyBytes is a valid compressed encoding by construction.
-            .decompress()
+        let p = p256::PublicKey::from_encoded_point(&self.0).unwrap();
-            .expect("EphemeralKeyBytes is a valid compressed encoding by construction")
+        p.to_encoded_point(false)
     }
 }
 
@@ -58,8 +66,8 @@ impl From<RecipientLine> for Stanza {
         Stanza {
             tag: STANZA_TAG.to_owned(),
             args: vec![
-                base64::encode_config(&r.tag, base64::STANDARD_NO_PAD),
+                BASE64_STANDARD_NO_PAD.encode(r.tag),
-                base64::encode_config(r.epk_bytes.as_bytes(), base64::STANDARD_NO_PAD),
+                BASE64_STANDARD_NO_PAD.encode(r.epk_bytes.as_bytes()),
             ],
             body: r.encrypted_file_key.to_vec(),
         }
@@ -77,9 +85,10 @@ impl RecipientLine {
                 return None;
             }
 
-            base64::decode_config_slice(arg, base64::STANDARD_NO_PAD, buf.as_mut())
+            BASE64_STANDARD_NO_PAD
+                .decode_slice_unchecked(arg, buf.as_mut())
                 .ok()
-                .map(|_| buf)
+                .and_then(|len| (len == buf.as_mut().len()).then_some(buf))
         }
 
         let (tag, epk_bytes) = match &s.args[..] {
@@ -102,17 +111,24 @@ impl RecipientLine {
     }
 
     pub(crate) fn wrap_file_key(file_key: &FileKey, pk: &Recipient) -> Self {
-        let esk = EphemeralSecret::random(OsRng);
+        let esk = EphemeralSecret::random(&mut OsRng);
         let epk = esk.public_key();
         let epk_bytes = EphemeralKeyBytes::from_public_key(&epk);
 
-        let shared_secret = esk.diffie_hellman(&pk.public_key());
+        let shared_secret = esk.diffie_hellman(pk.public_key());
 
         let mut salt = vec![];
         salt.extend_from_slice(epk_bytes.as_bytes());
         salt.extend_from_slice(pk.to_encoded().as_bytes());
 
-        let enc_key = hkdf(&salt, STANZA_KEY_LABEL, shared_secret.as_bytes());
+        let enc_key = {
+            let mut okm = [0; 32];
+            shared_secret
+                .extract::<Sha256>(Some(&salt))
+                .expand(STANZA_KEY_LABEL, &mut okm)
+                .expect("okm is the correct length");
+            okm
+        };
 
         let encrypted_file_key = {
             let mut key = [0; ENCRYPTED_FILE_KEY_BYTES];

src/key.rs

@@ -0,0 +1,813 @@
+//! Structs for handling YubiKeys.
+
+use age_core::{
+    format::{FileKey, FILE_KEY_BYTES},
+    primitives::{aead_decrypt, hkdf},
+    secrecy::{ExposeSecret, SecretString},
+};
+use age_plugin::{identity, Callbacks};
+use bech32::{ToBase32, Variant};
+use dialoguer::Password;
+use log::{debug, error, warn};
+use std::convert::Infallible;
+use std::fmt;
+use std::io;
+use std::iter;
+use std::thread::sleep;
+use std::time::{Duration, Instant, SystemTime};
+use x509_parser::der_parser::oid::Oid;
+use yubikey::{
+    certificate::Certificate,
+    piv::{decrypt_data, AlgorithmId, RetiredSlotId, SlotId},
+    reader::{Context, Reader},
+    Key, MgmKey, PinPolicy, Serial, TouchPolicy, YubiKey,
+};
+
+use crate::{
+    error::Error,
+    fl,
+    format::{RecipientLine, STANZA_KEY_LABEL},
+    p256::{Recipient, TAG_BYTES},
+    util::{otp_serial_prefix, Metadata, POLICY_EXTENSION_OID},
+    IDENTITY_PREFIX,
+};
+
+const ONE_SECOND: Duration = Duration::from_secs(1);
+const FIFTEEN_SECONDS: Duration = Duration::from_secs(15);
+
+/// The set of OIDs that we understand and use when parsing YubiKey slot certificates.
+const KNOWN_OIDS: &[&[u64]] = &[POLICY_EXTENSION_OID];
+
+pub(crate) fn is_connected(reader: Reader) -> bool {
+    filter_connected(&reader)
+}
+
+pub(crate) fn filter_connected(reader: &Reader) -> bool {
+    match reader.open() {
+        Err(yubikey::Error::PcscError {
+            inner: Some(pcsc::Error::NoSmartcard | pcsc::Error::RemovedCard),
+        }) => {
+            warn!(
+                "{}",
+                fl!("warn-yk-not-connected", yubikey_name = reader.name())
+            );
+            false
+        }
+        Err(yubikey::Error::AppletNotFound { applet_name }) => {
+            warn!(
+                "{}",
+                fl!(
+                    "warn-yk-missing-applet",
+                    yubikey_name = reader.name(),
+                    applet_name = applet_name,
+                ),
+            );
+            false
+        }
+        Err(_) => true,
+        Ok(yubikey) => {
+            // We only connected as a side-effect of confirming that we can connect, so
+            // avoid resetting the YubiKey.
+            disconnect_without_reset(yubikey);
+            true
+        }
+    }
+}
+
+pub(crate) fn wait_for_readers() -> Result<Context, Error> {
+    // Start a 15-second timer waiting for a YubiKey to be inserted (if necessary).
+    let start = SystemTime::now();
+    loop {
+        let mut readers = Context::open()?;
+        if readers.iter()?.any(is_connected) {
+            break Ok(readers);
+        }
+
+        match SystemTime::now().duration_since(start) {
+            Ok(end) if end >= FIFTEEN_SECONDS => return Err(Error::TimedOut),
+            _ => sleep(ONE_SECOND),
+        }
+    }
+}
+
+/// Looks for agent processes that might be holding exclusive access to a YubiKey, and
+/// asks them as nicely as possible to release it.
+///
+/// Returns `true` if any known agent was running and was successfully interrupted (or
+/// killed if the platform doesn't support interrupts).
+fn hunt_agents() -> bool {
+    debug!("Sharing violation encountered, looking for agent processes");
+
+    use sysinfo::{ProcessExt, ProcessRefreshKind, RefreshKind, Signal, System, SystemExt};
+
+    let mut interrupted = false;
+
+    let sys =
+        System::new_with_specifics(RefreshKind::new().with_processes(ProcessRefreshKind::new()));
+
+    for process in sys.processes().values() {
+        match process.name() {
+            "scdaemon" | "scdaemon.exe" => {
+                // gpg-agent runs scdaemon to interact with smart cards. The canonical way
+                // to reload it is `gpgconf --reload scdaemon`, which kills and restarts
+                // the process. We emulate that here with SIGINT (which it listens to).
+                if process
+                    .kill_with(Signal::Interrupt)
+                    .unwrap_or_else(|| process.kill())
+                {
+                    debug!("Stopped scdaemon (PID {})", process.pid());
+                    interrupted = true;
+                }
+            }
+            "yubikey-agent" | "yubikey-agent.exe" => {
+                // yubikey-agent releases all YubiKey locks when it receives a SIGHUP.
+                match process.kill_with(Signal::Hangup) {
+                    Some(true) => {
+                        debug!("Sent SIGHUP to yubikey-agent (PID {})", process.pid());
+                        interrupted = true;
+                    }
+                    Some(false) => (),
+                    None => debug!(
+                        "Found yubikey-agent (PID {}) but platform doesn't support SIGHUP",
+                        process.pid(),
+                    ),
+                }
+            }
+            _ => (),
+        }
+    }
+
+    // If we did interrupt an agent, pause briefly to allow it to finish up.
+    if interrupted {
+        sleep(Duration::from_millis(100));
+    }
+
+    interrupted
+}
+
+fn open_sesame(
+    op: impl Fn() -> Result<YubiKey, yubikey::Error>,
+) -> Result<YubiKey, yubikey::Error> {
+    op().or_else(|e| match e {
+        yubikey::Error::PcscError {
+            inner: Some(pcsc::Error::SharingViolation),
+        } if hunt_agents() => op(),
+        _ => Err(e),
+    })
+}
+
+/// Opens a connection to this reader, returning a `YubiKey` if successful.
+///
+/// This is equivalent to [`Reader::open`], but additionally handles the presence of
+/// agents (which can indefinitely hold exclusive access to a YubiKey).
+pub(crate) fn open_connection(reader: &Reader) -> Result<YubiKey, yubikey::Error> {
+    open_sesame(|| reader.open())
+}
+
+/// Opens a YubiKey with a specific serial number.
+///
+/// This is equivalent to [`YubiKey::open_by_serial`], but additionally handles the
+/// presence of agents (which can indefinitely hold exclusive access to a YubiKey).
+fn open_by_serial(serial: Serial) -> Result<YubiKey, yubikey::Error> {
+    // `YubiKey::open_by_serial` has a bug where it ignores all opening errors, even if
+    // it potentially could have found a matching YubiKey if not for an error, and thus
+    // returns `Error::NotFound` if another agent is holding exclusive access to the
+    // required YubiKey. This gives misleading UX behaviour where age-plugin-yubikey asks
+    // the user to insert a YubiKey they have already inserted.
+    //
+    // For now, we instead implement the correct behaviour manually. Once MSRV has been
+    // raised to 1.60, we can upstream this into the `yubikey` crate.
+    open_sesame(|| {
+        let mut readers = Context::open()?;
+
+        let mut open_error = None;
+
+        for reader in readers.iter()? {
+            let yubikey = match reader.open() {
+                Ok(yk) => yk,
+                Err(e) => {
+                    // Save the first error we see that indicates we might have been able
+                    // to find a matching YubiKey.
+                    if open_error.is_none() {
+                        if let yubikey::Error::PcscError {
+                            inner: Some(pcsc::Error::SharingViolation),
+                        } = e
+                        {
+                            open_error = Some(e);
+                        }
+                    }
+                    continue;
+                }
+            };
+
+            if serial == yubikey.serial() {
+                return Ok(yubikey);
+            } else {
+                // We didn't want this YubiKey; don't reset it.
+                disconnect_without_reset(yubikey);
+            }
+        }
+
+        Err(if let Some(e) = open_error {
+            e
+        } else {
+            error!("no YubiKey detected with serial: {}", serial);
+            yubikey::Error::NotFound
+        })
+    })
+}
+
+pub(crate) fn open(serial: Option<Serial>) -> Result<YubiKey, Error> {
+    if !Context::open()?.iter()?.any(is_connected) {
+        if let Some(serial) = serial {
+            eprintln!(
+                "{}",
+                fl!("open-yk-with-serial", yubikey_serial = serial.to_string())
+            );
+        } else {
+            eprintln!("{}", fl!("open-yk-without-serial"));
+        }
+    }
+    let mut readers = wait_for_readers()?;
+    let mut readers_iter = readers.iter()?.filter(filter_connected);
+
+    // --serial selects the YubiKey to use. If not provided, and more than one YubiKey is
+    // connected, an error is returned.
+    let yubikey = match (readers_iter.next(), readers_iter.next(), serial) {
+        (None, _, _) => unreachable!(),
+        (Some(reader), None, None) => open_connection(&reader)?,
+        (Some(reader), None, Some(serial)) => {
+            let yubikey = open_connection(&reader)?;
+            if yubikey.serial() != serial {
+                return Err(Error::NoMatchingSerial(serial));
+            }
+            yubikey
+        }
+        (Some(a), Some(b), Some(serial)) => {
+            let reader = iter::empty()
+                .chain(Some(a))
+                .chain(Some(b))
+                .chain(readers_iter)
+                .find(|reader| match open_connection(reader) {
+                    Ok(yk) => yk.serial() == serial,
+                    _ => false,
+                })
+                .ok_or(Error::NoMatchingSerial(serial))?;
+            open_connection(&reader)?
+        }
+        (Some(_), Some(_), None) => return Err(Error::MultipleYubiKeys),
+    };
+
+    Ok(yubikey)
+}
+
+/// Disconnect from the YubiKey without resetting it.
+///
+/// This can be used to preserve the YubiKey's PIN and touch caches. There are two cases
+/// where we want to do this:
+///
+/// - We connected to this YubiKey in a read-only context, so we have not made any changes
+///   to the YubiKey's state. However, we might have asked an agent to release the YubiKey
+///   in `key::open_connection`, and we want to allow any state it may have left behind
+///   (such as cached PINs or touches) to persist beyond our execution, for usability.
+/// - We opened this connection in a decryption context, so the only changes to the
+///   YubiKey's state were to potentially cache the PIN and/or touch (depending on the
+///   policies of the slot). We want to allow these to persist beyond our execution, for
+///   usability.
+pub(crate) fn disconnect_without_reset(yubikey: YubiKey) {
+    let _ = yubikey.disconnect(pcsc::Disposition::LeaveCard);
+}
+
+fn request_pin<E>(
+    mut prompt: impl FnMut(Option<String>) -> io::Result<Result<SecretString, E>>,
+    serial: Serial,
+) -> io::Result<Result<SecretString, E>> {
+    let mut prev_error = None;
+    loop {
+        prev_error = Some(match prompt(prev_error)? {
+            Ok(pin) => match pin.expose_secret().len() {
+                // A PIN must be between 6 and 8 characters.
+                6..=8 => break Ok(Ok(pin)),
+                // If the string is 44 bytes and starts with the YubiKey's serial
+                // encoded as 12-byte modhex, the user probably touched the YubiKey
+                // early and "typed" an OTP.
+                44 if pin.expose_secret().starts_with(&otp_serial_prefix(serial)) => {
+                    fl!("plugin-err-accidental-touch")
+                }
+                // Otherwise, the PIN is either too short or too long.
+                0..=5 => fl!("plugin-err-pin-too-short"),
+                _ => fl!("plugin-err-pin-too-long"),
+            },
+            Err(e) => break Ok(Err(e)),
+        });
+    }
+}
+
+pub(crate) fn manage(yubikey: &mut YubiKey) -> Result<(), Error> {
+    const DEFAULT_PIN: &str = "123456";
+    const DEFAULT_PUK: &str = "12345678";
+
+    eprintln!();
+    let pin = Password::new()
+        .with_prompt(fl!(
+            "mgr-enter-pin",
+            yubikey_serial = yubikey.serial().to_string(),
+            default_pin = DEFAULT_PIN,
+        ))
+        .report(true)
+        .interact()?;
+    yubikey.verify_pin(pin.as_bytes())?;
+
+    // If the user is using the default PIN, help them to change it.
+    if pin == DEFAULT_PIN {
+        eprintln!();
+        eprintln!("{}", fl!("mgr-change-default-pin"));
+        eprintln!();
+        let current_puk = Password::new()
+            .with_prompt(fl!("mgr-enter-current-puk", default_puk = DEFAULT_PUK))
+            .interact()?;
+        let new_pin = loop {
+            let pin = request_pin(
+                |prev_error| {
+                    if let Some(err) = prev_error {
+                        eprintln!("{}", err);
+                    }
+                    Password::new()
+                        .with_prompt(fl!("mgr-choose-new-pin"))
+                        .with_confirmation(fl!("mgr-repeat-new-pin"), fl!("mgr-pin-mismatch"))
+                        .interact()
+                        .map(|pin| Result::<_, Infallible>::Ok(SecretString::new(pin)))
+                },
+                yubikey.serial(),
+            )?
+            .unwrap();
+            if pin.expose_secret() == DEFAULT_PIN {
+                eprintln!("{}", fl!("mgr-nope-default-pin"));
+            } else {
+                break pin;
+            }
+        };
+        let new_pin = new_pin.expose_secret();
+        yubikey
+            .change_puk(current_puk.as_bytes(), new_pin.as_bytes())
+            .map_err(|e| match e {
+                yubikey::Error::PinLocked => Error::PukLocked,
+                yubikey::Error::WrongPin { tries } => Error::WrongPuk(tries),
+                _ => Error::YubiKey(e),
+            })?;
+        yubikey.change_pin(pin.as_bytes(), new_pin.as_bytes())?;
+    }
+
+    match MgmKey::get_protected(yubikey) {
+        Ok(mgm_key) => yubikey.authenticate(mgm_key).map_err(|e| match e {
+            yubikey::Error::AuthenticationError => Error::ManagementKeyAuth,
+            _ => e.into(),
+        })?,
+        Err(yubikey::Error::AuthenticationError) => Err(Error::ManagementKeyAuth)?,
+        _ => {
+            // Try to authenticate with the default management key.
+            yubikey
+                .authenticate(MgmKey::default())
+                .map_err(|_| Error::CustomManagementKey)?;
+
+            // Migrate to a PIN-protected management key.
+            let mgm_key = MgmKey::generate();
+            eprintln!();
+            eprintln!("{}", fl!("mgr-changing-mgmt-key"));
+            eprint!("... ");
+            mgm_key.set_protected(yubikey).map_err(|e| {
+                eprintln!(
+                    "{}",
+                    fl!(
+                        "mgr-changing-mgmt-key-error",
+                        management_key = hex::encode(mgm_key.as_ref()),
+                    )
+                );
+                e
+            })?;
+            eprintln!("{}", fl!("mgr-changing-mgmt-key-success"));
+        }
+    }
+
+    Ok(())
+}
+
+/// Parses the certificate to identify the preferred recipient type it corresponds to.
+pub(crate) fn identify_recipient(cert: &Certificate) -> Option<Recipient> {
+    let known_oids = KNOWN_OIDS
+        .iter()
+        .map(|oid| Oid::from(oid).unwrap())
+        .collect::<Vec<_>>();
+
+    // If the certificate contains any unrecognised critical extensions, reject it: we
+    // don't know how to correctly use the identity. In particular, some identities store
+    // parts of their private key material in certificate extensions to work around
+    // hardware limitations. Not understanding these extensions could lead to encrypting
+    // with the wrong protocol and violating security assumptions.
+    let (_, c) = x509_parser::parse_x509_certificate(cert.as_ref()).ok()?;
+    if c.tbs_certificate
+        .extensions()
+        .iter()
+        .any(|ext| ext.critical && !known_oids.contains(&ext.oid))
+    {
+        return None;
+    }
+
+    Recipient::from_certificate(cert)
+}
+
+/// Returns an iterator of keys that are occupying plugin-compatible slots, along with the
+/// corresponding recipient if the key is compatible with this plugin.
+pub(crate) fn list_slots(
+    yubikey: &mut YubiKey,
+) -> Result<impl Iterator<Item = (Key, RetiredSlotId, Option<Recipient>)>, Error> {
+    Ok(Key::list(yubikey)?.into_iter().filter_map(|key| {
+        // We only use the retired slots.
+        match key.slot() {
+            SlotId::Retired(slot) => {
+                let recipient = identify_recipient(key.certificate());
+                Some((key, slot, recipient))
+            }
+            _ => None,
+        }
+    }))
+}
+
+/// Returns an iterator of keys that are compatible with this plugin.
+pub(crate) fn list_compatible(
+    yubikey: &mut YubiKey,
+) -> Result<impl Iterator<Item = (Key, RetiredSlotId, Recipient)>, Error> {
+    list_slots(yubikey)
+        .map(|iter| iter.filter_map(|(key, slot, res)| res.map(|recipient| (key, slot, recipient))))
+}
+
+/// A reference to an age key stored in a YubiKey.
+#[derive(Debug)]
+pub struct Stub {
+    pub(crate) serial: Serial,
+    pub(crate) slot: RetiredSlotId,
+    pub(crate) tag: [u8; TAG_BYTES],
+    pub(crate) identity_index: usize,
+}
+
+impl fmt::Display for Stub {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(
+            bech32::encode(
+                IDENTITY_PREFIX,
+                self.to_bytes().to_base32(),
+                Variant::Bech32,
+            )
+            .expect("HRP is valid")
+            .to_uppercase()
+            .as_str(),
+        )
+    }
+}
+
+impl PartialEq for Stub {
+    fn eq(&self, other: &Self) -> bool {
+        self.to_bytes().eq(&other.to_bytes())
+    }
+}
+
+impl Stub {
+    /// Returns a key stub and recipient for this `(Serial, SlotId, PublicKey)` tuple.
+    ///
+    /// Does not check that the `PublicKey` matches the given `(Serial, SlotId)` tuple;
+    /// this is checked at decryption time.
+    pub(crate) fn new(serial: Serial, slot: RetiredSlotId, recipient: &Recipient) -> Self {
+        Stub {
+            serial,
+            slot,
+            tag: recipient.tag(),
+            identity_index: 0,
+        }
+    }
+
+    pub(crate) fn from_bytes(bytes: &[u8], identity_index: usize) -> Option<Self> {
+        if bytes.len() < 9 {
+            return None;
+        }
+        let serial = Serial::from(u32::from_le_bytes(bytes[0..4].try_into().unwrap()));
+        let slot: RetiredSlotId = bytes[4].try_into().ok()?;
+        Some(Stub {
+            serial,
+            slot,
+            tag: bytes[5..9].try_into().unwrap(),
+            identity_index,
+        })
+    }
+
+    fn to_bytes(&self) -> Vec<u8> {
+        let mut bytes = Vec::with_capacity(9);
+        bytes.extend_from_slice(&self.serial.0.to_le_bytes());
+        bytes.push(self.slot.into());
+        bytes.extend_from_slice(&self.tag);
+        bytes
+    }
+
+    pub(crate) fn matches(&self, line: &RecipientLine) -> bool {
+        self.tag == line.tag
+    }
+
+    /// Returns:
+    /// - `Ok(Ok(Some(connection)))` if we successfully connected to this YubiKey.
+    /// - `Ok(Ok(None))` if the user told us to skip this YubiKey.
+    /// - `Ok(Err(_))` if we encountered an error while trying to connect to the YubiKey.
+    /// - `Err(_)` on communication errors with the age client.
+    pub(crate) fn connect<E>(
+        &self,
+        callbacks: &mut dyn Callbacks<E>,
+    ) -> io::Result<Result<Option<Connection>, identity::Error>> {
+        let mut yubikey = match open_by_serial(self.serial) {
+            Ok(yk) => yk,
+            Err(yubikey::Error::NotFound) => {
+                let mut message = fl!("plugin-insert-yk", yubikey_serial = self.serial.to_string());
+
+                // If the `confirm` command is available, we loop until either the YubiKey
+                // we want is inserted, or the used explicitly skips.
+                let yubikey = loop {
+                    match callbacks.confirm(
+                        &message,
+                        &fl!("plugin-yk-is-plugged-in"),
+                        Some(&fl!("plugin-skip-this-yk")),
+                    )? {
+                        // `confirm` command is not available.
+                        Err(age_core::plugin::Error::Unsupported) => break None,
+                        // User told us to skip this key.
+                        Ok(false) => return Ok(Ok(None)),
+                        // User said they plugged it in; try it.
+                        Ok(true) => match open_by_serial(self.serial) {
+                            Ok(yubikey) => break Some(yubikey),
+                            Err(yubikey::Error::NotFound) => (),
+                            Err(_) => {
+                                return Ok(Err(identity::Error::Identity {
+                                    index: self.identity_index,
+                                    message: fl!(
+                                        "plugin-err-yk-opening",
+                                        yubikey_serial = self.serial.to_string(),
+                                    ),
+                                }));
+                            }
+                        },
+                        // We can't communicate with the user.
+                        Err(age_core::plugin::Error::Fail) => {
+                            return Ok(Err(identity::Error::Identity {
+                                index: self.identity_index,
+                                message: fl!(
+                                    "plugin-err-yk-opening",
+                                    yubikey_serial = self.serial.to_string(),
+                                ),
+                            }))
+                        }
+                    }
+
+                    // We're going to loop around, meaning that the first attempt failed.
+                    // Change the message to indicate this to the user.
+                    message = fl!(
+                        "plugin-insert-yk-retry",
+                        yubikey_serial = self.serial.to_string(),
+                    );
+                };
+
+                if let Some(yk) = yubikey {
+                    yk
+                } else {
+                    // `confirm` is not available; fall back to `message` with a timeout.
+                    if callbacks.message(&message)?.is_err() {
+                        return Ok(Err(identity::Error::Identity {
+                            index: self.identity_index,
+                            message: fl!(
+                                "plugin-err-yk-not-found",
+                                yubikey_serial = self.serial.to_string(),
+                            ),
+                        }));
+                    }
+
+                    // Start a 15-second timer waiting for the YubiKey to be inserted
+                    let start = SystemTime::now();
+                    loop {
+                        match open_by_serial(self.serial) {
+                            Ok(yubikey) => break yubikey,
+                            Err(yubikey::Error::NotFound) => (),
+                            Err(_) => {
+                                return Ok(Err(identity::Error::Identity {
+                                    index: self.identity_index,
+                                    message: fl!(
+                                        "plugin-err-yk-opening",
+                                        yubikey_serial = self.serial.to_string(),
+                                    ),
+                                }));
+                            }
+                        }
+
+                        match SystemTime::now().duration_since(start) {
+                            Ok(end) if end >= FIFTEEN_SECONDS => {
+                                return Ok(Err(identity::Error::Identity {
+                                    index: self.identity_index,
+                                    message: fl!(
+                                        "plugin-err-yk-timed-out",
+                                        yubikey_serial = self.serial.to_string(),
+                                    ),
+                                }))
+                            }
+                            _ => sleep(ONE_SECOND),
+                        }
+                    }
+                }
+            }
+            Err(_) => {
+                return Ok(Err(identity::Error::Identity {
+                    index: self.identity_index,
+                    message: fl!(
+                        "plugin-err-yk-opening",
+                        yubikey_serial = self.serial.to_string(),
+                    ),
+                }))
+            }
+        };
+
+        // Read the pubkey from the YubiKey slot and check it still matches.
+        let (cert, pk) = match Certificate::read(&mut yubikey, SlotId::Retired(self.slot))
+            .ok()
+            .and_then(|cert| {
+                identify_recipient(&cert)
+                    .filter(|recipient| recipient.tag() == self.tag)
+                    .map(|r| (cert, r))
+            }) {
+            Some(pk) => pk,
+            None => {
+                return Ok(Err(identity::Error::Identity {
+                    index: self.identity_index,
+                    message: fl!("plugin-err-yk-stub-mismatch"),
+                }))
+            }
+        };
+
+        Ok(Ok(Some(Connection {
+            yubikey,
+            cert,
+            pk,
+            slot: self.slot,
+            tag: self.tag,
+            identity_index: self.identity_index,
+            cached_metadata: None,
+            last_touch: None,
+        })))
+    }
+}
+
+pub(crate) struct Connection {
+    yubikey: YubiKey,
+    cert: Certificate,
+    pk: Recipient,
+    slot: RetiredSlotId,
+    tag: [u8; 4],
+    identity_index: usize,
+    cached_metadata: Option<Metadata>,
+    last_touch: Option<Instant>,
+}
+
+impl Connection {
+    pub(crate) fn recipient(&self) -> &Recipient {
+        &self.pk
+    }
+
+    pub(crate) fn request_pin_if_necessary<E>(
+        &mut self,
+        callbacks: &mut dyn Callbacks<E>,
+    ) -> io::Result<Result<(), identity::Error>> {
+        // Check if we can skip requesting a PIN.
+        if self.cached_metadata.is_none() {
+            self.cached_metadata =
+                match Metadata::extract(&mut self.yubikey, self.slot, &self.cert, true) {
+                    None => {
+                        return Ok(Err(identity::Error::Identity {
+                            index: self.identity_index,
+                            message: fl!("plugin-err-yk-invalid-pin-policy"),
+                        }))
+                    }
+                    metadata => metadata,
+                };
+        }
+        match self.cached_metadata.as_ref().and_then(|m| m.pin_policy) {
+            Some(PinPolicy::Never) => return Ok(Ok(())),
+            Some(PinPolicy::Once) if self.yubikey.verify_pin(&[]).is_ok() => return Ok(Ok(())),
+            _ => (),
+        }
+
+        // The policy requires a PIN, so request it.
+        let pin = match request_pin(
+            |prev_error| {
+                callbacks.request_secret(&format!(
+                    "{}{}{}",
+                    prev_error.as_deref().unwrap_or(""),
+                    prev_error.as_deref().map(|_| " ").unwrap_or(""),
+                    fl!(
+                        "plugin-enter-pin",
+                        yubikey_serial = self.yubikey.serial().to_string(),
+                    )
+                ))
+            },
+            self.yubikey.serial(),
+        )? {
+            Ok(pin) => pin,
+            Err(_) => {
+                return Ok(Err(identity::Error::Identity {
+                    index: self.identity_index,
+                    message: fl!(
+                        "plugin-err-pin-required",
+                        yubikey_serial = self.yubikey.serial().to_string(),
+                    ),
+                }))
+            }
+        };
+        if let Err(e) = self.yubikey.verify_pin(pin.expose_secret().as_bytes()) {
+            return Ok(Err(identity::Error::Identity {
+                index: self.identity_index,
+                message: format!("{:?}", Error::YubiKey(e)),
+            }));
+        }
+        Ok(Ok(()))
+    }
+
+    pub(crate) fn unwrap_file_key(&mut self, line: &RecipientLine) -> Result<FileKey, ()> {
+        assert_eq!(self.tag, line.tag);
+
+        // Check if the touch policy requires a touch.
+        let needs_touch = match (
+            self.cached_metadata.as_ref().and_then(|m| m.touch_policy),
+            self.last_touch,
+        ) {
+            (Some(TouchPolicy::Always), _) | (Some(TouchPolicy::Cached), None) => true,
+            (Some(TouchPolicy::Cached), Some(last)) if last.elapsed() >= FIFTEEN_SECONDS => true,
+            _ => false,
+        };
+
+        // The YubiKey API for performing scalar multiplication takes the point in its
+        // uncompressed SEC-1 encoding.
+        let shared_secret = match decrypt_data(
+            &mut self.yubikey,
+            line.epk_bytes.decompress().as_bytes(),
+            AlgorithmId::EccP256,
+            SlotId::Retired(self.slot),
+        ) {
+            Ok(res) => res,
+            Err(_) => return Err(()),
+        };
+
+        // If we requested a touch and reached here, the user touched the YubiKey.
+        if needs_touch {
+            if let Some(TouchPolicy::Cached) =
+                self.cached_metadata.as_ref().and_then(|m| m.touch_policy)
+            {
+                self.last_touch = Some(Instant::now());
+            }
+        }
+
+        let mut salt = vec![];
+        salt.extend_from_slice(line.epk_bytes.as_bytes());
+        salt.extend_from_slice(self.pk.to_encoded().as_bytes());
+
+        let enc_key = hkdf(&salt, STANZA_KEY_LABEL, shared_secret.as_ref());
+
+        // A failure to decrypt is fatal, because we assume that we won't
+        // encounter 32-bit collisions on the key tag embedded in the header.
+        match aead_decrypt(&enc_key, FILE_KEY_BYTES, &line.encrypted_file_key) {
+            Ok(pt) => Ok(TryInto::<[u8; FILE_KEY_BYTES]>::try_into(&pt[..])
+                .unwrap()
+                .into()),
+            Err(_) => Err(()),
+        }
+    }
+
+    /// Close this connection without resetting the YubiKey.
+    ///
+    /// This can be used to preserve the YubiKey's PIN and touch caches.
+    pub(crate) fn disconnect_without_reset(self) {
+        disconnect_without_reset(self.yubikey);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use yubikey::{piv::RetiredSlotId, Serial};
+
+    use super::Stub;
+
+    #[test]
+    fn stub_round_trip() {
+        let stub = Stub {
+            serial: Serial::from(42),
+            slot: RetiredSlotId::R1,
+            tag: [7; 4],
+            identity_index: 0,
+        };
+
+        let encoded = stub.to_bytes();
+        assert_eq!(Stub::from_bytes(&[], 0), None);
+        assert_eq!(Stub::from_bytes(&encoded, 0), Some(stub));
+        assert_eq!(Stub::from_bytes(&encoded[..encoded.len() - 1], 0), None);
+    }
+}

src/main.rs

@@ -1,24 +1,26 @@
-use std::convert::{TryFrom, TryInto};
+#![forbid(unsafe_code)]
+
 use std::fs::{File, OpenOptions};
 use std::io::{self, Write};
 
 use age_plugin::run_state_machine;
 use dialoguer::{Confirm, Input, Select};
 use gumdrop::Options;
-use yubikey_piv::{
+use i18n_embed::{
-    certificate::PublicKeyInfo,
+    fluent::{fluent_language_loader, FluentLanguageLoader},
-    key::{RetiredSlotId, SlotId},
+    DesktopLanguageRequester,
-    policy::{PinPolicy, TouchPolicy},
-    Key, Readers, Serial,
 };
+use lazy_static::lazy_static;
+use rust_embed::RustEmbed;
+use yubikey::{piv::RetiredSlotId, reader::Context, PinPolicy, Serial, TouchPolicy};
 
 mod builder;
 mod error;
 mod format;
+mod key;
 mod p256;
 mod plugin;
 mod util;
-mod yubikey;
 
 use error::Error;
 
@@ -51,6 +53,26 @@ const USABLE_SLOTS: [RetiredSlotId; 20] = [
     RetiredSlotId::R20,
 ];
 
+#[derive(RustEmbed)]
+#[folder = "i18n"]
+struct Translations;
+
+const TRANSLATIONS: Translations = Translations {};
+
+lazy_static! {
+    static ref LANGUAGE_LOADER: FluentLanguageLoader = fluent_language_loader!();
+}
+
+#[macro_export]
+macro_rules! fl {
+    ($message_id:literal) => {{
+        i18n_embed_fl::fl!($crate::LANGUAGE_LOADER, $message_id)
+    }};
+    ($message_id:literal, $($kwarg:expr),* $(,)*) => {{
+        i18n_embed_fl::fl!($crate::LANGUAGE_LOADER, $message_id, $($kwarg,)*)
+    }};
+}
+
 #[derive(Debug, Options)]
 struct PluginOptions {
     #[options(help = "Print this help message and exit.")]
@@ -148,7 +170,7 @@ impl TryFrom<PluginOptions> for PluginFlags {
 }
 
 fn generate(flags: PluginFlags) -> Result<(), Error> {
-    let mut yubikey = yubikey::open(flags.serial)?;
+    let mut yubikey = key::open(flags.serial)?;
 
     let (stub, recipient, metadata) = builder::IdentityBuilder::new(flags.slot)
         .with_name(flags.name)
@@ -159,39 +181,34 @@ fn generate(flags: PluginFlags) -> Result<(), Error> {
 
     util::print_identity(stub, recipient, metadata);
 
+    // We have written to the YubiKey, which means we've authenticated with the management
+    // key. Out of an abundance of caution, we let the YubiKey be reset on disconnect,
+    // which will clear its PIN and touch caches. This has as small negative UX effect,
+    // but identity generation is a relatively infrequent occurrence, and users are more
+    // likely to see their cached PINs reset due to switching applets (e.g. from PIV to
+    // FIDO2).
+
     Ok(())
 }
 
 fn print_single(
     serial: Option<Serial>,
     slot: RetiredSlotId,
-    printer: impl Fn(yubikey::Stub, p256::Recipient, util::Metadata),
+    printer: impl Fn(key::Stub, p256::Recipient, util::Metadata),
 ) -> Result<(), Error> {
-    let mut yubikey = yubikey::open(serial)?;
+    let mut yubikey = key::open(serial)?;
 
-    let mut keys = Key::list(&mut yubikey)?.into_iter().filter_map(|key| {
+    let (key, slot, recipient) = key::list_compatible(&mut yubikey)?
-        // - We only use the retired slots.
-        // - Only P-256 keys are compatible with us.
-        match (key.slot(), key.certificate().subject_pki()) {
-            (SlotId::Retired(slot), PublicKeyInfo::EcP256(pubkey)) => {
-                p256::Recipient::from_encoded(pubkey).map(|r| (key, slot, r))
-            }
-            _ => None,
-        }
-    });
-
-    let (key, slot, recipient) = keys
         .find(|(_, s, _)| s == &slot)
         .ok_or(Error::SlotHasNoIdentity(slot))?;
 
-    let stub = yubikey::Stub::new(yubikey.serial(), slot, &recipient);
+    let stub = key::Stub::new(yubikey.serial(), slot, &recipient);
-    let metadata = x509_parser::parse_x509_certificate(key.certificate().as_ref())
+    let metadata = util::Metadata::extract(&mut yubikey, slot, key.certificate(), true).unwrap();
-        .ok()
-        .and_then(|(_, cert)| util::Metadata::extract(&mut yubikey, slot, &cert, true))
-        .unwrap();
 
     printer(stub, recipient, metadata);
 
+    key::disconnect_without_reset(yubikey);
+
     Ok(())
 }
 
@@ -199,39 +216,22 @@ fn print_multiple(
     kind: &str,
     serial: Option<Serial>,
     all: bool,
-    printer: impl Fn(yubikey::Stub, p256::Recipient, util::Metadata),
+    printer: impl Fn(key::Stub, p256::Recipient, util::Metadata),
 ) -> Result<(), Error> {
-    let mut readers = Readers::open()?;
+    let mut readers = Context::open()?;
 
     let mut printed = 0;
-    for reader in readers.iter()?.filter(yubikey::filter_connected) {
+    for reader in readers.iter()?.filter(key::filter_connected) {
-        let mut yubikey = reader.open()?;
+        let mut yubikey = key::open_connection(&reader)?;
         if let Some(serial) = serial {
             if yubikey.serial() != serial {
                 continue;
             }
         }
 
-        for key in Key::list(&mut yubikey)? {
+        for (key, slot, recipient) in key::list_compatible(&mut yubikey)? {
-            // We only use the retired slots.
+            let stub = key::Stub::new(yubikey.serial(), slot, &recipient);
-            let slot = match key.slot() {
+            let metadata = match util::Metadata::extract(&mut yubikey, slot, key.certificate(), all)
-                SlotId::Retired(slot) => slot,
-                _ => continue,
-            };
-
-            // Only P-256 keys are compatible with us.
-            let recipient = match key.certificate().subject_pki() {
-                PublicKeyInfo::EcP256(pubkey) => match p256::Recipient::from_encoded(pubkey) {
-                    Some(recipient) => recipient,
-                    None => continue,
-                },
-                _ => continue,
-            };
-
-            let stub = yubikey::Stub::new(yubikey.serial(), slot, &recipient);
-            let metadata = match x509_parser::parse_x509_certificate(key.certificate().as_ref())
-                .ok()
-                .and_then(|(_, cert)| util::Metadata::extract(&mut yubikey, slot, &cert, all))
             {
                 Some(res) => res,
                 None => continue,
@@ -242,12 +242,11 @@ fn print_multiple(
             println!();
         }
         println!();
+
+        key::disconnect_without_reset(yubikey);
     }
     if printed > 1 {
-        eprintln!(
+        eprintln!("{}", fl!("printed-multiple", kind = kind, count = printed));
-            "Generated {} for {} slots. If you intended to select a slot, use --slot.",
-            kind, printed,
-        );
     }
 
     Ok(())
@@ -257,7 +256,7 @@ fn print_details(
     kind: &str,
     flags: PluginFlags,
     all: bool,
-    printer: impl Fn(yubikey::Stub, p256::Recipient, util::Metadata),
+    printer: impl Fn(key::Stub, p256::Recipient, util::Metadata),
 ) -> Result<(), Error> {
     if let Some(slot) = flags.slot {
         print_single(flags.serial, slot, printer)
@@ -273,7 +272,12 @@ fn identity(flags: PluginFlags) -> Result<(), Error> {
             "--identity".into(),
         ));
     }
-    print_details("identities", flags, false, util::print_identity)
+    print_details(
+        &fl!("printed-kind-identities"),
+        flags,
+        false,
+        util::print_identity,
+    )
 }
 
 fn list(flags: PluginFlags, all: bool) -> Result<(), Error> {
@@ -287,10 +291,15 @@ fn list(flags: PluginFlags, all: bool) -> Result<(), Error> {
         ));
     }
 
-    print_details("recipients", flags, all, |_, recipient, metadata| {
+    print_details(
+        &fl!("printed-kind-recipients"),
+        flags,
+        all,
+        |_, recipient, metadata| {
             println!("{}", metadata);
-        println!("{}", recipient.to_string());
+            println!("{}", recipient);
-    })
+        },
+    )
 }
 
 fn main() -> Result<(), Error> {
@@ -300,6 +309,12 @@ fn main() -> Result<(), Error> {
         .parse_default_env()
         .init();
 
+    let requested_languages = DesktopLanguageRequester::requested_languages();
+    i18n_embed::select(&*LANGUAGE_LOADER, &TRANSLATIONS, &requested_languages).unwrap();
+    // Unfortunately the common Windows terminals don't support Unicode Directionality
+    // Isolation Marks, so we disable them for now.
+    LANGUAGE_LOADER.set_use_isolating(false);
+
     let opts = PluginOptions::parse_args_default_or_exit();
 
     if [opts.generate, opts.identity, opts.list, opts.list_all]
@@ -335,69 +350,71 @@ fn main() -> Result<(), Error> {
         }
         let flags: PluginFlags = opts.try_into()?;
 
-        eprintln!("✨ Let's get your YubiKey set up for age! ✨");
+        eprintln!(
-        eprintln!();
+            "{}",
-        eprintln!("This tool can create a new age identity in a free slot of your YubiKey.");
+            fl!(
-        eprintln!("It will generate an identity file that you can use with an age client,");
+                "cli-setup-intro",
-        eprintln!("along with the corresponding recipient. You can also do this directly");
+                generate_usage = "age-plugin-yubikey --generate",
-        eprintln!("with:");
+            )
-        eprintln!("    age-plugin-yubikey --generate");
+        );
-        eprintln!();
-        eprintln!("If you are already using a YubiKey with age, you can select an existing");
-        eprintln!("slot to recreate its corresponding identity file and recipient.");
-        eprintln!();
-        eprintln!("When asked below to select an option, use the up/down arrow keys to");
-        eprintln!("make your choice, or press [Esc] or [q] to quit.");
         eprintln!();
 
-        if !Readers::open()?.iter()?.any(yubikey::is_connected) {
+        if !Context::open()?.iter()?.any(key::is_connected) {
-            eprintln!("⏳ Please insert the YubiKey you want to set up.");
+            eprintln!("{}", fl!("cli-setup-insert-yk"));
         };
-        let mut readers = yubikey::wait_for_readers()?;
+        let mut readers = key::wait_for_readers()?;
 
         // Filter out readers we can't connect to.
-        let readers_list: Vec<_> = readers.iter()?.filter(yubikey::filter_connected).collect();
+        let readers_list: Vec<_> = readers.iter()?.filter(key::filter_connected).collect();
 
         let reader_names = readers_list
             .iter()
             .map(|reader| {
-                reader
+                key::open_connection(reader).map(|yk| {
-                    .open()
+                    let name = fl!(
-                    .map(|yk| format!("{} (Serial: {})", reader.name(), yk.serial()))
+                        "cli-setup-yk-name",
+                        yubikey_name = reader.name(),
+                        yubikey_serial = yk.serial().to_string(),
+                    );
+                    key::disconnect_without_reset(yk);
+                    name
+                })
             })
             .collect::<Result<Vec<_>, _>>()?;
         let mut yubikey = match Select::new()
-            .with_prompt("🔑 Select a YubiKey")
+            .with_prompt(fl!("cli-setup-select-yk"))
             .items(&reader_names)
             .default(0)
+            .report(true)
             .interact_opt()?
         {
             Some(yk) => readers_list[yk].open()?,
             None => return Ok(()),
         };
 
-        let keys = Key::list(&mut yubikey)?;
+        let keys = key::list_slots(&mut yubikey)?.collect::<Vec<_>>();
 
         // Identify slots that we can't allow the user to select.
         let slot_details: Vec<_> = USABLE_SLOTS
             .iter()
             .map(|&slot| {
                 keys.iter()
-                    .find(|key| key.slot() == SlotId::Retired(slot))
+                    .find(|(_, s, _)| s == &slot)
-                    .map(|key| match key.certificate().subject_pki() {
+                    .map(|(key, _, recipient)| {
-                        PublicKeyInfo::EcP256(pubkey) => {
+                        recipient.as_ref().map(|_| {
-                            p256::Recipient::from_encoded(pubkey).map(|_| {
                             // Cache the details we need to display to the user.
                             let (_, cert) =
                                 x509_parser::parse_x509_certificate(key.certificate().as_ref())
                                     .unwrap();
                             let (name, _) = util::extract_name(&cert, true).unwrap();
-                                let created = cert.validity().not_before.to_rfc2822();
+                            let created = cert
+                                .validity()
+                                .not_before
+                                .to_rfc2822()
+                                .unwrap_or_else(|e| format!("Invalid date: {}", e));
 
                             format!("{}, created: {}", name, created)
                         })
-                        }
-                        _ => None,
                     })
             })
             .collect();
@@ -410,9 +427,13 @@ fn main() -> Result<(), Error> {
                 let i = i + 1;
 
                 match occupied {
-                    Some(Some(name)) => format!("Slot {} ({})", i, name),
+                    Some(Some(name)) => fl!(
-                    Some(None) => format!("Slot {} (Unusable)", i),
+                        "cli-setup-slot-usable",
-                    None => format!("Slot {} (Empty)", i),
+                        slot_index = i,
+                        slot_name = name.as_str(),
+                    ),
+                    Some(None) => fl!("cli-setup-slot-unusable", slot_index = i),
+                    None => fl!("cli-setup-slot-empty", slot_index = i),
                 }
             })
             .collect();
@@ -420,9 +441,10 @@ fn main() -> Result<(), Error> {
         let ((stub, recipient, metadata), is_new) = {
             let (slot_index, slot) = loop {
                 match Select::new()
-                    .with_prompt("🕳️  Select a slot for your age identity")
+                    .with_prompt(fl!("cli-setup-select-slot"))
                     .items(&slots)
                     .default(0)
+                    .report(true)
                     .interact_opt()?
                 {
                     Some(slot) => {
@@ -435,43 +457,44 @@ fn main() -> Result<(), Error> {
                 }
             };
 
-            if let Some(key) = keys.iter().find(|key| key.slot() == SlotId::Retired(slot)) {
+            if let Some((key, _, recipient)) = keys.into_iter().find(|(_, s, _)| s == &slot) {
-                let recipient = match key.certificate().subject_pki() {
+                let recipient = recipient.expect("We checked this above");
-                    PublicKeyInfo::EcP256(pubkey) => {
-                        p256::Recipient::from_encoded(pubkey).expect("We checked this above")
-                    }
-                    _ => unreachable!(),
-                };
 
                 if Confirm::new()
-                    .with_prompt(&format!("Use existing identity in slot {}?", slot_index))
+                    .with_prompt(fl!("cli-setup-use-existing", slot_index = slot_index))
+                    .report(true)
                     .interact()?
                 {
-                    let stub = yubikey::Stub::new(yubikey.serial(), slot, &recipient);
+                    let stub = key::Stub::new(yubikey.serial(), slot, &recipient);
-                    let (_, cert) =
-                        x509_parser::parse_x509_certificate(key.certificate().as_ref()).unwrap();
                     let metadata =
-                        util::Metadata::extract(&mut yubikey, slot, &cert, true).unwrap();
+                        util::Metadata::extract(&mut yubikey, slot, key.certificate(), true)
+                            .unwrap();
 
+                    key::disconnect_without_reset(yubikey);
                     ((stub, recipient, metadata), false)
                 } else {
+                    key::disconnect_without_reset(yubikey);
                     return Ok(());
                 }
             } else {
                 let name = Input::<String>::new()
                     .with_prompt(format!(
-                        "📛 Name this identity [{}]",
+                        "{} [{}]",
+                        fl!("cli-setup-name-identity"),
                         flags.name.as_deref().unwrap_or("age identity TAG_HEX")
                     ))
                     .allow_empty(true)
+                    .report(true)
                     .interact_text()?;
 
+                let mut displayed_yk4_warning = false;
+                let pin_policy = loop {
                     let pin_policy = match Select::new()
-                    .with_prompt("🔤 Select a PIN policy")
+                        .with_prompt(fl!("cli-setup-select-pin-policy"))
                         .items(&[
-                        "Always (A PIN is required for every decryption, if set)",
+                            fl!("pin-policy-always"),
-                        "Once   (A PIN is required once per session, if set)",
+                            fl!("pin-policy-once"),
-                        "Never  (A PIN is NOT required to decrypt)",
+                            fl!("pin-policy-never"),
                         ])
                         .default(
                             [PinPolicy::Always, PinPolicy::Once, PinPolicy::Never]
@@ -481,6 +504,7 @@ fn main() -> Result<(), Error> {
                                 })
                                 .unwrap(),
                         )
+                        .report(true)
                         .interact_opt()?
                     {
                         Some(0) => PinPolicy::Always,
@@ -490,20 +514,45 @@ fn main() -> Result<(), Error> {
                         None => return Ok(()),
                     };
 
+                    // We can't preserve the PIN cache for YubiKey 4 series, because to
+                    // retrieve the serial we switch to the OTP applet.
+                    match (pin_policy, yubikey.version().major) {
+                        (PinPolicy::Once, 4) => {
+                            if !displayed_yk4_warning {
+                                eprintln!();
+                                eprintln!("{}", fl!("cli-setup-yk4-pin-policy"));
+                                eprintln!();
+                                displayed_yk4_warning = true;
+                            }
+
+                            if Confirm::new()
+                                .with_prompt(fl!("cli-setup-yk4-pin-policy-confirm"))
+                                .report(true)
+                                .interact()?
+                            {
+                                break pin_policy;
+                            }
+                        }
+                        _ => break pin_policy,
+                    }
+                };
+
                 let touch_policy = match Select::new()
-                        .with_prompt("👆 Select a touch policy")
+                    .with_prompt(fl!("cli-setup-select-touch-policy"))
                     .items(&[
-                            "Always (A physical touch is required for every decryption)",
+                        fl!("touch-policy-always"),
-                            "Cached (A physical touch is required for decryption, and is cached for 15 seconds)",
+                        fl!("touch-policy-cached"),
-                            "Never  (A physical touch is NOT required to decrypt)",
+                        fl!("touch-policy-never"),
                     ])
                     .default(
                         [TouchPolicy::Always, TouchPolicy::Cached, TouchPolicy::Never]
                             .iter()
-                                .position(|p| p == &flags
+                            .position(|p| {
-                                    .touch_policy.unwrap_or(builder::DEFAULT_TOUCH_POLICY))
+                                p == &flags.touch_policy.unwrap_or(builder::DEFAULT_TOUCH_POLICY)
+                            })
                             .unwrap(),
                     )
+                    .report(true)
                     .interact_opt()?
                 {
                     Some(0) => TouchPolicy::Always,
@@ -514,7 +563,8 @@ fn main() -> Result<(), Error> {
                 };
 
                 if Confirm::new()
-                    .with_prompt(&format!("Generate new identity in slot {}?", slot_index))
+                    .with_prompt(fl!("cli-setup-generate-new", slot_index = slot_index))
+                    .report(true)
                     .interact()?
                 {
                     eprintln!();
@@ -530,6 +580,7 @@ fn main() -> Result<(), Error> {
                         true,
                     )
                 } else {
+                    key::disconnect_without_reset(yubikey);
                     return Ok(());
                 }
             }
@@ -537,11 +588,12 @@ fn main() -> Result<(), Error> {
 
         eprintln!();
         let file_name = Input::<String>::new()
-            .with_prompt("📝 File name to write this identity to")
+            .with_prompt(fl!("cli-setup-identity-file-name"))
             .default(format!(
                 "age-yubikey-identity-{}.txt",
                 hex::encode(stub.tag)
             ))
+            .report(true)
             .interact_text()?;
 
         let mut file = match OpenOptions::new()
@@ -552,7 +604,8 @@ fn main() -> Result<(), Error> {
             Ok(file) => file,
             Err(e) if e.kind() == io::ErrorKind::AlreadyExists => {
                 if Confirm::new()
-                    .with_prompt("File exists. Overwrite it?")
+                    .with_prompt(fl!("cli-setup-identity-file-exists"))
+                    .report(true)
                     .interact()?
                 {
                     File::create(&file_name)?
@@ -563,54 +616,54 @@ fn main() -> Result<(), Error> {
             Err(e) => return Err(e.into()),
         };
 
-        writeln!(file, "{}", metadata)?;
+        writeln!(
-        writeln!(file, "#    Recipient: {}", recipient)?;
+            file,
-        writeln!(file, "{}", stub.to_string())?;
+            "{}",
+            fl!(
+                "yubikey-identity",
+                yubikey_metadata = metadata.to_string(),
+                recipient = recipient.to_string(),
+                identity = stub.to_string(),
+            )
+        )?;
         file.sync_data()?;
 
         // If `rage` binary is installed, use it in examples. Otherwise default to `age`.
         let age_binary = which::which("rage").map(|_| "rage").unwrap_or("age");
 
-        eprintln!();
+        let encrypt_usage = format!(
-        eprintln!("✅ Done! This YubiKey identity is ready to go.");
-        eprintln!();
-        if is_new {
-            eprintln!("🔑 Here's your shiny new YubiKey recipient:");
-        } else {
-            eprintln!("🔑 Here's the corresponding YubiKey recipient:");
-        }
-        eprintln!("  {}", recipient);
-        eprintln!();
-        eprintln!("Here are some example things you can do with it:");
-        eprintln!();
-        eprintln!("- Encrypt a file to this identity:");
-        eprintln!(
             "$ cat foo.txt | {} -r {} -o foo.txt.age",
             age_binary, recipient
         );
-        eprintln!();
+        let decrypt_usage = format!(
-        eprintln!("- Decrypt a file with this identity:");
-        eprintln!(
             "$ cat foo.txt.age | {} -d -i {} > foo.txt",
             age_binary, file_name
         );
-        eprintln!();
+        let identity_usage = format!(
-        eprintln!("- Recreate the identity file:");
-        eprintln!(
             "$ age-plugin-yubikey -i --serial {} --slot {} > {}",
             stub.serial,
             util::slot_to_ui(&stub.slot),
             file_name,
         );
-        eprintln!();
+        let recipient_usage = format!(
-        eprintln!("- Recreate the recipient:");
-        eprintln!(
             "$ age-plugin-yubikey -l --serial {} --slot {}",
             stub.serial,
             util::slot_to_ui(&stub.slot),
         );
+
         eprintln!();
-        eprintln!("💭 Remember: everything breaks, have a backup plan for when this YubiKey does.");
+        eprintln!(
+            "{}",
+            fl!(
+                "cli-setup-finished",
+                is_new = if is_new { "true" } else { "false" },
+                recipient = recipient.to_string(),
+                encrypt_usage = encrypt_usage,
+                decrypt_usage = decrypt_usage,
+                identity_usage = identity_usage,
+                recipient_usage = recipient_usage,
+            )
+        );
 
         Ok(())
     }

src/p256.rs

@@ -1,7 +1,8 @@
 use bech32::{ToBase32, Variant};
 use p256::elliptic_curve::sec1::{FromEncodedPoint, ToEncodedPoint};
 use sha2::{Digest, Sha256};
-use std::convert::TryInto;
+use yubikey::{certificate::PublicKeyInfo, Certificate};
+
 use std::fmt;
 
 use crate::RECIPIENT_PREFIX;
@@ -43,12 +44,23 @@ impl Recipient {
         }
     }
 
+    pub(crate) fn from_certificate(cert: &Certificate) -> Option<Self> {
+        Self::from_spki(cert.subject_pki())
+    }
+
+    pub(crate) fn from_spki(spki: &PublicKeyInfo) -> Option<Self> {
+        match spki {
+            PublicKeyInfo::EcP256(pubkey) => Self::from_encoded(pubkey),
+            _ => None,
+        }
+    }
+
     /// Attempts to parse a valid YubiKey recipient from its SEC-1 encoding.
     ///
     /// This accepts both compressed (as used by the plugin) and uncompressed (as used in
     /// the YubiKey certificate) encodings.
-    pub(crate) fn from_encoded(encoded: &p256::EncodedPoint) -> Option<Self> {
+    fn from_encoded(encoded: &p256::EncodedPoint) -> Option<Self> {
-        p256::PublicKey::from_encoded_point(&encoded).map(Recipient)
+        Option::from(p256::PublicKey::from_encoded_point(encoded)).map(Recipient)
     }
 
     /// Returns the compressed SEC-1 encoding of this recipient.

src/plugin.rs

@@ -7,12 +7,12 @@ use age_plugin::{
 use std::collections::HashMap;
 use std::io;
 
-use crate::{format, p256::Recipient, yubikey, PLUGIN_NAME};
+use crate::{fl, format, key, p256::Recipient, PLUGIN_NAME};
 
 #[derive(Debug, Default)]
 pub(crate) struct RecipientPlugin {
     recipients: Vec<Recipient>,
-    yubikeys: Vec<yubikey::Stub>,
+    yubikeys: Vec<key::Stub>,
 }
 
 impl RecipientPluginV1 for RecipientPlugin {
@@ -23,7 +23,7 @@ impl RecipientPluginV1 for RecipientPlugin {
         bytes: &[u8],
     ) -> Result<(), recipient::Error> {
         if let Some(pk) = if plugin_name == PLUGIN_NAME {
-            Recipient::from_bytes(&bytes)
+            Recipient::from_bytes(bytes)
         } else {
             None
         } {
@@ -32,7 +32,7 @@ impl RecipientPluginV1 for RecipientPlugin {
         } else {
             Err(recipient::Error::Recipient {
                 index,
-                message: "Invalid recipient".to_owned(),
+                message: fl!("plugin-err-invalid-recipient"),
             })
         }
     }
@@ -44,7 +44,7 @@ impl RecipientPluginV1 for RecipientPlugin {
         bytes: &[u8],
     ) -> Result<(), recipient::Error> {
         if let Some(stub) = if plugin_name == PLUGIN_NAME {
-            yubikey::Stub::from_bytes(&bytes, index)
+            key::Stub::from_bytes(bytes, index)
         } else {
             None
         } {
@@ -53,7 +53,7 @@ impl RecipientPluginV1 for RecipientPlugin {
         } else {
             Err(recipient::Error::Identity {
                 index,
-                message: "Invalid Yubikey stub".to_owned(),
+                message: fl!("plugin-err-invalid-identity"),
             })
         }
     }
@@ -68,7 +68,14 @@ impl RecipientPluginV1 for RecipientPlugin {
         let mut yk_errors = vec![];
         for stub in &self.yubikeys {
             match stub.connect(&mut callbacks)? {
-                Ok(conn) => yk_recipients.push(conn.recipient().clone()),
+                Ok(Some(conn)) => yk_recipients.push(conn.recipient().clone()),
+                Ok(None) => yk_errors.push(recipient::Error::Identity {
+                    index: stub.identity_index,
+                    message: fl!(
+                        "plugin-err-yk-opening",
+                        yubikey_serial = stub.serial.to_string(),
+                    ),
+                }),
                 Err(e) => yk_errors.push(match e {
                     identity::Error::Identity { index, message } => {
                         recipient::Error::Identity { index, message }
@@ -88,7 +95,7 @@ impl RecipientPluginV1 for RecipientPlugin {
                     self.recipients
                         .iter()
                         .chain(yk_recipients.iter())
-                        .map(|pk| format::RecipientLine::wrap_file_key(&file_key, &pk).into())
+                        .map(|pk| format::RecipientLine::wrap_file_key(&file_key, pk).into())
                         .collect()
                 })
                 .collect())
@@ -100,7 +107,7 @@ impl RecipientPluginV1 for RecipientPlugin {
 
 #[derive(Debug, Default)]
 pub(crate) struct IdentityPlugin {
-    yubikeys: Vec<yubikey::Stub>,
+    yubikeys: Vec<key::Stub>,
 }
 
 impl IdentityPluginV1 for IdentityPlugin {
@@ -111,7 +118,7 @@ impl IdentityPluginV1 for IdentityPlugin {
         bytes: &[u8],
     ) -> Result<(), identity::Error> {
         if let Some(stub) = if plugin_name == PLUGIN_NAME {
-            yubikey::Stub::from_bytes(&bytes, index)
+            key::Stub::from_bytes(bytes, index)
         } else {
             None
         } {
@@ -120,7 +127,7 @@ impl IdentityPluginV1 for IdentityPlugin {
         } else {
             Err(identity::Error::Identity {
                 index,
-                message: "Invalid Yubikey stub".to_owned(),
+                message: fl!("plugin-err-invalid-identity"),
             })
         }
     }
@@ -133,11 +140,8 @@ impl IdentityPluginV1 for IdentityPlugin {
         let mut file_keys = HashMap::with_capacity(files.len());
 
         // Filter to files / stanzas for which we have matching YubiKeys
-        let mut candidate_stanzas: Vec<(
+        let mut candidate_stanzas: Vec<(&key::Stub, HashMap<usize, Vec<format::RecipientLine>>)> =
-            &yubikey::Stub,
+            self.yubikeys
-            HashMap<usize, Vec<format::RecipientLine>>,
-        )> = self
-            .yubikeys
                 .iter()
                 .map(|stub| (stub, HashMap::new()))
                 .collect();
@@ -145,11 +149,11 @@ impl IdentityPluginV1 for IdentityPlugin {
         for (file, stanzas) in files.iter().enumerate() {
             for (stanza_index, stanza) in stanzas.iter().enumerate() {
                 match (
-                    format::RecipientLine::from_stanza(&stanza).map(|res| {
+                    format::RecipientLine::from_stanza(stanza).map(|res| {
                         res.map_err(|_| identity::Error::Stanza {
                             file_index: file,
                             stanza_index,
-                            message: "Invalid yubikey stanza".to_owned(),
+                            message: fl!("plugin-err-invalid-stanza"),
                         })
                     }),
                     file_keys.contains_key(&file),
@@ -206,13 +210,22 @@ impl IdentityPluginV1 for IdentityPlugin {
 
         for (stub, files) in candidate_stanzas.iter() {
             let mut conn = match stub.connect(&mut callbacks)? {
-                Ok(conn) => conn,
+                // The user skipped this YubiKey.
+                Ok(None) => continue,
+                // We connected to this YubiKey.
+                Ok(Some(conn)) => conn,
+                // We failed to connect to this YubiKey.
                 Err(e) => {
                     callbacks.error(e)?.unwrap();
                     continue;
                 }
             };
 
+            if let Err(e) = conn.request_pin_if_necessary(&mut callbacks)? {
+                callbacks.error(e)?.unwrap();
+                continue;
+            }
+
             for (&file_index, stanzas) in files {
                 if file_keys.contains_key(&file_index) {
                     // We decrypted this file with an earlier YubiKey.
@@ -220,7 +233,7 @@ impl IdentityPluginV1 for IdentityPlugin {
                 }
 
                 for (stanza_index, line) in stanzas.iter().enumerate() {
-                    match conn.unwrap_file_key(&line) {
+                    match conn.unwrap_file_key(line) {
                         Ok(file_key) => {
                             // We've managed to decrypt this file!
                             file_keys.entry(file_index).or_insert(Ok(file_key));
@@ -230,12 +243,14 @@ impl IdentityPluginV1 for IdentityPlugin {
                             .error(identity::Error::Stanza {
                                 file_index,
                                 stanza_index,
-                                message: "Failed to decrypt YubiKey stanza".to_owned(),
+                                message: fl!("plugin-err-decryption-failed"),
                             })?
                             .unwrap(),
                     }
                 }
             }
+
+            conn.disconnect_without_reset();
         }
         Ok(file_keys)
     }

src/util.rs

@@ -1,13 +1,14 @@
 use std::fmt;
+use std::iter;
 
 use x509_parser::{certificate::X509Certificate, der_parser::oid::Oid};
-use yubikey_piv::{
+use yubikey::{
-    key::{RetiredSlotId, SlotId},
+    piv::{RetiredSlotId, SlotId},
-    policy::{PinPolicy, TouchPolicy},
+    Certificate, PinPolicy, Serial, TouchPolicy, YubiKey,
-    Serial, YubiKey,
 };
 
-use crate::{error::Error, p256::Recipient, yubikey::Stub, BINARY_NAME, USABLE_SLOTS};
+use crate::fl;
+use crate::{error::Error, key::Stub, p256::Recipient, BINARY_NAME, USABLE_SLOTS};
 
 pub(crate) const POLICY_EXTENSION_OID: &[u64] = &[1, 3, 6, 1, 4, 1, 41482, 3, 8];
 
@@ -42,24 +43,31 @@ pub(crate) fn touch_policy_from_string(s: String) -> Result<TouchPolicy, Error>
     }
 }
 
-pub(crate) fn pin_policy_to_str(policy: Option<PinPolicy>) -> &'static str {
+pub(crate) fn pin_policy_to_str(policy: Option<PinPolicy>) -> String {
     match policy {
-        Some(PinPolicy::Always) => "Always (A PIN is required for every decryption, if set)",
+        Some(PinPolicy::Always) => fl!("pin-policy-always"),
-        Some(PinPolicy::Once) => "Once   (A PIN is required once per session, if set)",
+        Some(PinPolicy::Once) => fl!("pin-policy-once"),
-        Some(PinPolicy::Never) => "Never  (A PIN is NOT required to decrypt)",
+        Some(PinPolicy::Never) => fl!("pin-policy-never"),
-        _ => "Unknown",
+        _ => fl!("unknown-policy"),
     }
 }
 
-pub(crate) fn touch_policy_to_str(policy: Option<TouchPolicy>) -> &'static str {
+pub(crate) fn touch_policy_to_str(policy: Option<TouchPolicy>) -> String {
     match policy {
-        Some(TouchPolicy::Always) => "Always (A physical touch is required for every decryption)",
+        Some(TouchPolicy::Always) => fl!("touch-policy-always"),
-        Some(TouchPolicy::Cached) => {
+        Some(TouchPolicy::Cached) => fl!("touch-policy-cached"),
-            "Cached (A physical touch is required for decryption, and is cached for 15 seconds)"
+        Some(TouchPolicy::Never) => fl!("touch-policy-never"),
+        _ => fl!("unknown-policy"),
     }
-        Some(TouchPolicy::Never) => "Never  (A physical touch is NOT required to decrypt)",
-        _ => "Unknown",
 }
+
+const MODHEX: &str = "cbdefghijklnrtuv";
+pub(crate) fn otp_serial_prefix(serial: Serial) -> String {
+    iter::repeat(0)
+        .take(4)
+        .chain((0..8).rev().map(|i| (serial.0 >> (4 * i)) & 0x0f))
+        .map(|i| MODHEX.char_indices().nth(i as usize).unwrap().1)
+        .collect()
 }
 
 pub(crate) fn extract_name(cert: &X509Certificate, all: bool) -> Option<(String, bool)> {
@@ -96,23 +104,28 @@ pub(crate) struct Metadata {
     slot: RetiredSlotId,
     name: String,
     created: String,
-    pin_policy: Option<PinPolicy>,
+    pub(crate) pin_policy: Option<PinPolicy>,
-    touch_policy: Option<TouchPolicy>,
+    pub(crate) touch_policy: Option<TouchPolicy>,
 }
 
 impl Metadata {
     pub(crate) fn extract(
         yubikey: &mut YubiKey,
         slot: RetiredSlotId,
-        cert: &X509Certificate,
+        cert: &Certificate,
         all: bool,
     ) -> Option<Self> {
+        let (_, cert) = x509_parser::parse_x509_certificate(cert.as_ref()).ok()?;
+
         // We store the PIN and touch policies for identities in their certificates
         // using the same certificate extension as PIV attestations.
         // https://developers.yubico.com/PIV/Introduction/PIV_attestation.html
         let policies = |c: &X509Certificate| {
-            c.extensions()
+            c.tbs_certificate
-                .get(&Oid::from(POLICY_EXTENSION_OID).unwrap())
+                .get_extension_unique(&Oid::from(POLICY_EXTENSION_OID).unwrap())
+                // If the extension is duplicated, we assume it is invalid.
+                .ok()
+                .flatten()
                 // If the encoded extension doesn't have 2 bytes, we assume it is invalid.
                 .filter(|policy| policy.value.len() >= 2)
                 .map(|policy| {
@@ -135,7 +148,7 @@ impl Metadata {
                 .unwrap_or((None, None))
         };
 
-        extract_name(cert, all)
+        extract_name(&cert, all)
             .map(|(name, ours)| {
                 if ours {
                     let (pin_policy, touch_policy) = policies(&cert);
@@ -144,7 +157,7 @@ impl Metadata {
                     // We can extract the PIN and touch policies via an attestation. This
                     // is slow, but the user has asked for all compatible keys, so...
                     let (pin_policy, touch_policy) =
-                        yubikey_piv::key::attest(yubikey, SlotId::Retired(slot))
+                        yubikey::piv::attest(yubikey, SlotId::Retired(slot))
                             .ok()
                             .and_then(|buf| {
                                 x509_parser::parse_x509_certificate(&buf)
@@ -160,7 +173,11 @@ impl Metadata {
                 serial: yubikey.serial(),
                 slot,
                 name,
-                created: cert.validity().not_before.to_rfc2822(),
+                created: cert
+                    .validity()
+                    .not_before
+                    .to_rfc2822()
+                    .unwrap_or_else(|e| format!("Invalid date: {}", e)),
                 pin_policy,
                 touch_policy,
             })
@@ -169,19 +186,18 @@ impl Metadata {
 
 impl fmt::Display for Metadata {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        writeln!(
-            f,
-            "#       Serial: {}, Slot: {}",
-            self.serial,
-            slot_to_ui(&self.slot)
-        )?;
-        writeln!(f, "#         Name: {}", self.name)?;
-        writeln!(f, "#      Created: {}", self.created)?;
-        writeln!(f, "#   PIN policy: {}", pin_policy_to_str(self.pin_policy))?;
         write!(
             f,
-            "# Touch policy: {}",
+            "{}",
-            touch_policy_to_str(self.touch_policy)
+            fl!(
+                "yubikey-metadata",
+                serial = self.serial.to_string(),
+                slot = slot_to_ui(&self.slot),
+                name = self.name.as_str(),
+                created = self.created.as_str(),
+                pin_policy = pin_policy_to_str(self.pin_policy),
+                touch_policy = touch_policy_to_str(self.touch_policy),
+            )
         )
     }
 }
@@ -189,10 +205,17 @@ impl fmt::Display for Metadata {
 pub(crate) fn print_identity(stub: Stub, recipient: Recipient, metadata: Metadata) {
     let recipient = recipient.to_string();
     if !console::user_attended() {
-        eprintln!("Recipient: {}", recipient);
+        let recipient = recipient.as_str();
+        eprintln!("{}", fl!("print-recipient", recipient = recipient));
     }
 
-    println!("{}", metadata);
+    println!(
-    println!("#    Recipient: {}", recipient);
+        "{}",
-    println!("{}", stub.to_string());
+        fl!(
+            "yubikey-identity",
+            yubikey_metadata = metadata.to_string(),
+            recipient = recipient,
+            identity = stub.to_string(),
+        )
+    );
 }

src/yubikey.rs

@@ -1,409 +0,0 @@
-//! Structs for handling YubiKeys.
-
-use age_core::{
-    format::{FileKey, FILE_KEY_BYTES},
-    primitives::{aead_decrypt, hkdf},
-};
-use age_plugin::{identity, Callbacks};
-use bech32::{ToBase32, Variant};
-use dialoguer::Password;
-use log::warn;
-use secrecy::ExposeSecret;
-use std::convert::TryInto;
-use std::fmt;
-use std::io;
-use std::iter;
-use std::thread::sleep;
-use std::time::{Duration, SystemTime};
-use yubikey_piv::{
-    certificate::{Certificate, PublicKeyInfo},
-    key::{decrypt_data, AlgorithmId, RetiredSlotId, SlotId},
-    readers::Reader,
-    yubikey::Serial,
-    MgmKey, Readers, YubiKey,
-};
-
-use crate::{
-    error::Error,
-    format::{RecipientLine, STANZA_KEY_LABEL},
-    p256::{Recipient, TAG_BYTES},
-    IDENTITY_PREFIX,
-};
-
-const ONE_SECOND: Duration = Duration::from_secs(1);
-const FIFTEEN_SECONDS: Duration = Duration::from_secs(15);
-
-pub(crate) fn is_connected(reader: Reader) -> bool {
-    filter_connected(&reader)
-}
-
-pub(crate) fn filter_connected(reader: &Reader) -> bool {
-    match reader.open() {
-        Ok(_) => true,
-        Err(e) => {
-            use std::error::Error;
-            if let Some(pcsc::Error::RemovedCard) =
-                e.source().and_then(|inner| inner.downcast_ref())
-            {
-                warn!("Ignoring {}: not connected", reader.name());
-                false
-            } else {
-                true
-            }
-        }
-    }
-}
-
-pub(crate) fn wait_for_readers() -> Result<Readers, Error> {
-    // Start a 15-second timer waiting for a YubiKey to be inserted (if necessary).
-    let start = SystemTime::now();
-    loop {
-        let mut readers = Readers::open()?;
-        if readers.iter()?.any(is_connected) {
-            break Ok(readers);
-        }
-
-        match SystemTime::now().duration_since(start) {
-            Ok(end) if end >= FIFTEEN_SECONDS => return Err(Error::TimedOut),
-            _ => sleep(ONE_SECOND),
-        }
-    }
-}
-
-pub(crate) fn open(serial: Option<Serial>) -> Result<YubiKey, Error> {
-    if !Readers::open()?.iter()?.any(is_connected) {
-        if let Some(serial) = serial {
-            eprintln!("⏳ Please insert the YubiKey with serial {}.", serial);
-        } else {
-            eprintln!("⏳ Please insert the YubiKey.");
-        }
-    }
-    let mut readers = wait_for_readers()?;
-    let mut readers_iter = readers.iter()?.filter(filter_connected);
-
-    // --serial selects the YubiKey to use. If not provided, and more than one YubiKey is
-    // connected, an error is returned.
-    let yubikey = match (readers_iter.next(), readers_iter.next(), serial) {
-        (None, _, _) => unreachable!(),
-        (Some(reader), None, None) => reader.open()?,
-        (Some(reader), None, Some(serial)) => {
-            let yubikey = reader.open()?;
-            if yubikey.serial() != serial {
-                return Err(Error::NoMatchingSerial(serial));
-            }
-            yubikey
-        }
-        (Some(a), Some(b), Some(serial)) => {
-            let reader = iter::empty()
-                .chain(Some(a))
-                .chain(Some(b))
-                .chain(readers_iter)
-                .find(|reader| match reader.open() {
-                    Ok(yk) => yk.serial() == serial,
-                    _ => false,
-                })
-                .ok_or(Error::NoMatchingSerial(serial))?;
-            reader.open()?
-        }
-        (Some(_), Some(_), None) => return Err(Error::MultipleYubiKeys),
-    };
-
-    Ok(yubikey)
-}
-
-pub(crate) fn manage(yubikey: &mut YubiKey) -> Result<(), Error> {
-    eprintln!();
-    let pin = Password::new()
-        .with_prompt(&format!(
-            "Enter PIN for YubiKey with serial {} (default is 123456)",
-            yubikey.serial(),
-        ))
-        .interact()?;
-    yubikey.verify_pin(pin.as_bytes())?;
-
-    // If the user is using the default PIN, help them to change it.
-    if pin == "123456" {
-        eprintln!();
-        eprintln!("✨ Your YubiKey is using the default PIN. Let's change it!");
-        eprintln!("✨ We'll also set the PUK equal to the PIN.");
-        eprintln!();
-        eprintln!("🔐 The PIN is up to 8 numbers, letters, or symbols. Not just numbers!");
-        eprintln!(
-            "❌ Your keys will be lost if the PIN and PUK are locked after 3 incorrect tries."
-        );
-        eprintln!();
-        let current_puk = Password::new()
-            .with_prompt("Enter current PUK (default is 12345678)")
-            .interact()?;
-        let new_pin = Password::new()
-            .with_prompt("Choose a new PIN/PUK")
-            .with_confirmation("Repeat the PIN/PUK", "PINs don't match")
-            .interact()?;
-        if new_pin.len() > 8 {
-            return Err(Error::InvalidPinLength);
-        }
-        yubikey.change_puk(current_puk.as_bytes(), new_pin.as_bytes())?;
-        yubikey.change_pin(pin.as_bytes(), new_pin.as_bytes())?;
-    }
-
-    if let Ok(mgm_key) = MgmKey::get_protected(yubikey) {
-        yubikey.authenticate(mgm_key)?;
-    } else {
-        // Try to authenticate with the default management key.
-        yubikey
-            .authenticate(MgmKey::default())
-            .map_err(|_| Error::CustomManagementKey)?;
-
-        // Migrate to a PIN-protected management key.
-        let mgm_key = MgmKey::generate()?;
-        eprintln!();
-        eprintln!("✨ Your YubiKey is using the default management key.");
-        eprintln!("✨ We'll migrate it to a PIN-protected management key.");
-        eprint!("... ");
-        mgm_key.set_protected(yubikey).map_err(|e| {
-            eprintln!("An error occurred while setting the new management key.");
-            eprintln!("⚠️ SAVE THIS MANAGEMENT KEY - YOU MAY NEED IT TO MANAGE YOUR YubiKey! ⚠️");
-            eprintln!("  {}", hex::encode(mgm_key.as_ref()));
-            e
-        })?;
-        eprintln!("Success!");
-    }
-
-    Ok(())
-}
-
-/// A reference to an age key stored in a YubiKey.
-#[derive(Debug)]
-pub struct Stub {
-    pub(crate) serial: Serial,
-    pub(crate) slot: RetiredSlotId,
-    pub(crate) tag: [u8; TAG_BYTES],
-    identity_index: usize,
-}
-
-impl fmt::Display for Stub {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str(
-            bech32::encode(
-                IDENTITY_PREFIX,
-                self.to_bytes().to_base32(),
-                Variant::Bech32,
-            )
-            .expect("HRP is valid")
-            .to_uppercase()
-            .as_str(),
-        )
-    }
-}
-
-impl PartialEq for Stub {
-    fn eq(&self, other: &Self) -> bool {
-        self.to_bytes().eq(&other.to_bytes())
-    }
-}
-
-impl Stub {
-    /// Returns a key stub and recipient for this `(Serial, SlotId, PublicKey)` tuple.
-    ///
-    /// Does not check that the `PublicKey` matches the given `(Serial, SlotId)` tuple;
-    /// this is checked at decryption time.
-    pub(crate) fn new(serial: Serial, slot: RetiredSlotId, recipient: &Recipient) -> Self {
-        Stub {
-            serial,
-            slot,
-            tag: recipient.tag(),
-            identity_index: 0,
-        }
-    }
-
-    pub(crate) fn from_bytes(bytes: &[u8], identity_index: usize) -> Option<Self> {
-        let serial = Serial::from(u32::from_le_bytes(bytes[0..4].try_into().unwrap()));
-        let slot: RetiredSlotId = bytes[4].try_into().ok()?;
-        Some(Stub {
-            serial,
-            slot,
-            tag: bytes[5..9].try_into().unwrap(),
-            identity_index,
-        })
-    }
-
-    fn to_bytes(&self) -> Vec<u8> {
-        let mut bytes = Vec::with_capacity(9);
-        bytes.extend_from_slice(&self.serial.0.to_le_bytes());
-        bytes.push(self.slot.into());
-        bytes.extend_from_slice(&self.tag);
-        bytes
-    }
-
-    pub(crate) fn matches(&self, line: &RecipientLine) -> bool {
-        self.tag == line.tag
-    }
-
-    pub(crate) fn connect<E>(
-        &self,
-        callbacks: &mut dyn Callbacks<E>,
-    ) -> io::Result<Result<Connection, identity::Error>> {
-        let mut yubikey = match YubiKey::open_by_serial(self.serial) {
-            Ok(yk) => yk,
-            Err(yubikey_piv::Error::NotFound) => {
-                if callbacks
-                    .message(&format!(
-                        "Please insert YubiKey with serial {}",
-                        self.serial
-                    ))?
-                    .is_err()
-                {
-                    return Ok(Err(identity::Error::Identity {
-                        index: self.identity_index,
-                        message: format!("Could not find YubiKey with serial {}", self.serial),
-                    }));
-                }
-
-                // Start a 15-second timer waiting for the YubiKey to be inserted
-                let start = SystemTime::now();
-                loop {
-                    match YubiKey::open_by_serial(self.serial) {
-                        Ok(yubikey) => break yubikey,
-                        Err(yubikey_piv::Error::NotFound) => (),
-                        Err(_) => {
-                            return Ok(Err(identity::Error::Identity {
-                                index: self.identity_index,
-                                message: format!(
-                                    "Could not open YubiKey with serial {}",
-                                    self.serial
-                                ),
-                            }));
-                        }
-                    }
-
-                    match SystemTime::now().duration_since(start) {
-                        Ok(end) if end >= FIFTEEN_SECONDS => {
-                            return Ok(Err(identity::Error::Identity {
-                                index: self.identity_index,
-                                message: format!(
-                                "Timed out while waiting for YubiKey with serial {} to be inserted",
-                                self.serial
-                            ),
-                            }))
-                        }
-                        _ => sleep(ONE_SECOND),
-                    }
-                }
-            }
-            Err(_) => {
-                return Ok(Err(identity::Error::Identity {
-                    index: self.identity_index,
-                    message: format!("Could not open YubiKey with serial {}", self.serial),
-                }))
-            }
-        };
-
-        // Read the pubkey from the YubiKey slot and check it still matches.
-        let pk = match Certificate::read(&mut yubikey, SlotId::Retired(self.slot))
-            .ok()
-            .and_then(|cert| match cert.subject_pki() {
-                PublicKeyInfo::EcP256(pubkey) => {
-                    Recipient::from_encoded(pubkey).filter(|pk| pk.tag() == self.tag)
-                }
-                _ => None,
-            }) {
-            Some(pk) => pk,
-            None => {
-                return Ok(Err(identity::Error::Identity {
-                    index: self.identity_index,
-                    message: "A YubiKey stub did not match the YubiKey".to_owned(),
-                }))
-            }
-        };
-
-        let pin = match callbacks.request_secret(&format!(
-            "Enter PIN for YubiKey with serial {}",
-            self.serial
-        ))? {
-            Ok(pin) => pin,
-            Err(_) => {
-                return Ok(Err(identity::Error::Identity {
-                    index: self.identity_index,
-                    message: format!("A PIN is required for YubiKey with serial {}", self.serial),
-                }))
-            }
-        };
-        if yubikey.verify_pin(pin.expose_secret().as_bytes()).is_err() {
-            return Ok(Err(identity::Error::Identity {
-                index: self.identity_index,
-                message: "Invalid YubiKey PIN".to_owned(),
-            }));
-        }
-
-        Ok(Ok(Connection {
-            yubikey,
-            pk,
-            slot: self.slot,
-            tag: self.tag,
-        }))
-    }
-}
-
-pub(crate) struct Connection {
-    yubikey: YubiKey,
-    pk: Recipient,
-    slot: RetiredSlotId,
-    tag: [u8; 4],
-}
-
-impl Connection {
-    pub(crate) fn recipient(&self) -> &Recipient {
-        &self.pk
-    }
-
-    pub(crate) fn unwrap_file_key(&mut self, line: &RecipientLine) -> Result<FileKey, ()> {
-        assert_eq!(self.tag, line.tag);
-
-        // The YubiKey API for performing scalar multiplication takes the point in its
-        // uncompressed SEC-1 encoding.
-        let shared_secret = match decrypt_data(
-            &mut self.yubikey,
-            line.epk_bytes.decompress().as_bytes(),
-            AlgorithmId::EccP256,
-            SlotId::Retired(self.slot),
-        ) {
-            Ok(res) => res,
-            Err(_) => return Err(()),
-        };
-
-        let mut salt = vec![];
-        salt.extend_from_slice(line.epk_bytes.as_bytes());
-        salt.extend_from_slice(self.pk.to_encoded().as_bytes());
-
-        let enc_key = hkdf(&salt, STANZA_KEY_LABEL, shared_secret.as_ref());
-
-        // A failure to decrypt is fatal, because we assume that we won't
-        // encounter 32-bit collisions on the key tag embedded in the header.
-        match aead_decrypt(&enc_key, FILE_KEY_BYTES, &line.encrypted_file_key) {
-            Ok(pt) => Ok(TryInto::<[u8; FILE_KEY_BYTES]>::try_into(&pt[..])
-                .unwrap()
-                .into()),
-            Err(_) => Err(()),
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use yubikey_piv::{key::RetiredSlotId, Serial};
-
-    use super::Stub;
-
-    #[test]
-    fn stub_round_trip() {
-        let stub = Stub {
-            serial: Serial::from(42),
-            slot: RetiredSlotId::R1,
-            tag: [7; 4],
-            identity_index: 0,
-        };
-
-        let encoded = stub.to_bytes();
-        assert_eq!(Stub::from_bytes(&encoded, 0), Some(stub));
-    }
-}

tests/integration.rs

@@ -0,0 +1,125 @@
+use std::env;
+use std::io::Write;
+use std::path::Path;
+use std::process::{Command, Stdio};
+
+const PLUGIN_BIN: &str = env!("CARGO_BIN_EXE_age-plugin-yubikey");
+
+#[test_with::env(YUBIKEY_SERIAL, YUBIKEY_SLOT)]
+#[cfg_attr(all(unix, not(target_os = "macos")), test_with::executable(pcscd))]
+#[test]
+fn recipient_and_identity_match() {
+    let recipient = Command::new(PLUGIN_BIN)
+        .arg("--list")
+        .arg("--serial")
+        .arg(env::var("YUBIKEY_SERIAL").unwrap())
+        .arg("--slot")
+        .arg(env::var("YUBIKEY_SLOT").unwrap())
+        .output()
+        .unwrap();
+    assert_eq!(recipient.status.code(), Some(0));
+
+    let identity = Command::new(PLUGIN_BIN)
+        .arg("--identity")
+        .arg("--serial")
+        .arg(env::var("YUBIKEY_SERIAL").unwrap())
+        .arg("--slot")
+        .arg(env::var("YUBIKEY_SLOT").unwrap())
+        .output()
+        .unwrap();
+    assert_eq!(identity.status.code(), Some(0));
+
+    let recipient_file = String::from_utf8_lossy(&recipient.stdout);
+    let recipient = recipient_file.lines().last().unwrap();
+    let identity = String::from_utf8_lossy(&identity.stdout);
+    assert!(identity.contains(recipient));
+}
+
+#[test_with::executable(rage)]
+#[test]
+fn plugin_encrypt() {
+    let enc_file = tempfile::NamedTempFile::new_in(env!("CARGO_TARGET_TMPDIR")).unwrap();
+
+    let mut process = Command::new(which::which("rage").unwrap())
+        .arg("-r")
+        .arg("age1yubikey1q2w7u3vpya839jxxuq8g0sedh3d740d4xvn639sqhr95ejj8vu3hyfumptt")
+        .arg("-o")
+        .arg(enc_file.path())
+        .stdin(Stdio::piped())
+        .env("PATH", Path::new(PLUGIN_BIN).parent().unwrap())
+        .spawn()
+        .unwrap();
+
+    // Scope to ensure stdin is closed.
+    {
+        let mut stdin = process.stdin.take().unwrap();
+        stdin.write_all(b"Testing YubiKey encryption").unwrap();
+        stdin.flush().unwrap();
+    }
+
+    let status = process.wait().unwrap();
+    assert_eq!(status.code(), Some(0));
+}
+
+#[test_with::env(YUBIKEY_SERIAL, YUBIKEY_SLOT)]
+#[test_with::executable(rage)]
+#[cfg_attr(all(unix, not(target_os = "macos")), test_with::executable(pcscd))]
+#[test]
+fn plugin_decrypt() {
+    let mut identity_file = tempfile::NamedTempFile::new_in(env!("CARGO_TARGET_TMPDIR")).unwrap();
+    let enc_file = tempfile::NamedTempFile::new_in(env!("CARGO_TARGET_TMPDIR")).unwrap();
+    let plaintext = "Testing YubiKey encryption";
+
+    // Write an identity file corresponding to this YubiKey slot.
+    let identity = Command::new(PLUGIN_BIN)
+        .arg("--identity")
+        .arg("--serial")
+        .arg(env::var("YUBIKEY_SERIAL").unwrap())
+        .arg("--slot")
+        .arg(env::var("YUBIKEY_SLOT").unwrap())
+        .output()
+        .unwrap();
+    assert_eq!(identity.status.code(), Some(0));
+    identity_file.write_all(&identity.stdout).unwrap();
+    identity_file.flush().unwrap();
+
+    // Encrypt to the YubiKey slot.
+    let mut enc_process = Command::new(which::which("rage").unwrap())
+        .arg("-e")
+        .arg("-i")
+        .arg(identity_file.path())
+        .arg("-o")
+        .arg(enc_file.path())
+        .stdin(Stdio::piped())
+        .env("PATH", Path::new(PLUGIN_BIN).parent().unwrap())
+        .spawn()
+        .unwrap();
+
+    // Scope to ensure stdin is closed.
+    {
+        let mut stdin = enc_process.stdin.take().unwrap();
+        stdin.write_all(plaintext.as_bytes()).unwrap();
+        stdin.flush().unwrap();
+    }
+
+    let enc_status = enc_process.wait().unwrap();
+    assert_eq!(enc_status.code(), Some(0));
+
+    // Decrypt with the YubiKey.
+    let dec_process = Command::new(which::which("rage").unwrap())
+        .arg("-d")
+        .arg("-i")
+        .arg(identity_file.path())
+        .arg(enc_file.path())
+        .stdin(Stdio::piped())
+        .env("PATH", Path::new(PLUGIN_BIN).parent().unwrap())
+        .output()
+        .unwrap();
+
+    let stderr = String::from_utf8_lossy(&dec_process.stderr);
+    if !stderr.is_empty() {
+        assert!(stderr.contains("age-plugin-yubikey"));
+        assert!(stderr.ends_with("...\n"));
+    }
+    assert_eq!(String::from_utf8_lossy(&dec_process.stdout), plaintext);
+}