yubikey v0.9.0-pre.0 (#666 )

This prerelease includes crates from the new RustCrypto release series including prereleases for crates which haven't yet received a new stable release. It also includes preliminary Curve25519/Ed25519 support.
Upgrade dependencies; bump version to v0.9.0-pre (#665 )
2026-04-02 13:59:53 -06:00 · 2026-04-02 13:35:37 -06:00 · 2026-02-18 17:27:43 -07:00 · 2025-12-15 19:59:48 +01:00 · 2025-12-15 19:59:04 +01:00 · 2025-12-15 18:08:36 +01:00
31 changed files with 2980 additions and 2014 deletions
@@ -2,4 +2,5 @@
 ignore = [
    "RUSTSEC-2020-0071", # chrono
    "RUSTSEC-2021-0145", # atty
+    "RUSTSEC-2023-0071", # rsa: Marvin Attack: potential key recovery
 ] # advisory IDs to ignore e.g. ["RUSTSEC-2019-0001", ...]
@@ -1,8 +1,19 @@
 version: 2
 updates:
  - package-ecosystem: cargo
+    versioning-strategy: lockfile-only
+    directory: "/"
+    allow:
+      - dependency-type: "all"
+    groups:
+      all-deps:
+        patterns:
+          - "*"
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 10
+  - package-ecosystem: github-actions
    directory: "/"
    schedule:
      interval: weekly
-    time: '13:00'
    open-pull-requests-limit: 10
@@ -13,7 +13,7 @@ jobs:
  check:
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v6
      - uses: actions-rs/toolchain@v1
        with:
          profile: minimal
@@ -36,17 +36,17 @@ jobs:
            toolchain: stable
            deps: true
          - platform: ubuntu-latest
-            toolchain: 1.65.0 # MSRV
+            toolchain: 1.85.0 # MSRV
            deps: sudo apt-get install libpcsclite-dev
          - platform: windows-latest
-            toolchain: 1.65.0 # MSRV
+            toolchain: 1.85.0 # MSRV
            deps: true
          - platform: macos-latest
-            toolchain: 1.65.0 # MSRV
+            toolchain: 1.85.0 # MSRV
            deps: true
    runs-on: ${{ matrix.platform }}
    steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v6
      - uses: actions-rs/toolchain@v1
        with:
          profile: minimal
@@ -60,7 +60,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout sources
-        uses: actions/checkout@v1
+        uses: actions/checkout@v6

      - name: Install stable toolchain
        uses: actions-rs/toolchain@v1
@@ -78,11 +78,11 @@ jobs:
  clippy:
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v6
      - uses: actions-rs/toolchain@v1
        with:
          profile: minimal
-          toolchain: 1.65.0
+          toolchain: 1.85.0 # MSRV
          components: clippy
          override: true
      - run: sudo apt-get install libpcsclite-dev
@@ -15,16 +15,16 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout sources
-        uses: actions/checkout@v1
+        uses: actions/checkout@v6

      - name: Cache cargo registry
-        uses: actions/cache@v1
+        uses: actions/cache@v5
        with:
          path: ~/.cargo/registry
          key: ${{ runner.os }}-cargo-registry-${{ hashFiles('Cargo.lock') }}

      - name: Cache cargo index
-        uses: actions/cache@v1
+        uses: actions/cache@v5
        with:
          path: ~/.cargo/git
          key: ${{ runner.os }}-cargo-index-${{ hashFiles('Cargo.lock') }}
@@ -6,9 +6,52 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0

 ## Unreleased
 ### Added
- `YubiKey::disconnect`
- `impl Debug for {Context, YubiKey}`
- `Error::AppletNotFound`
+- `yubikey::certificate::SelfSigned`
+- `yubikey::Error::CertificateBuilder`
+- `yubikey::MgmAlgorithmId`
+- `yubikey::mgm`:
+  - `MgmKey::generate_for`
+  - `MgmKey::get_default`
+  - `impl AsRef<[u8]> for MgmKey`
+
+### Changed
+- MSRV is now 1.81.
+- Migrated the public API to the following (pre-release) dependencies:
+  - `der 0.8.0-rc.1`
+  - `ecdsa 0.17.0-pre.9`
+  - `p256 0.14.0-pre.2`
+  - `p384 0.14.0-pre.2`
+  - `rsa 0.10.0-pre.3`
+  - `sha2 0.11.0-pre.4`
+  - `x509-cert 0.3.0-pre.0`
+- `yubikey::mgm`:
+  - `MgmKey::generate` now takes a `rand::TryCryptoRng` argument.
+  - `MgmKey::generate` now requires the caller to specify the key algorithm via
+    an `MgmAlgorithmId` parameter.
+    - Use `MgmKey::generate_for` if you want to generate a key using the
+      preferred algorithm for a given Yubikey's firmware version.
+  - `MgmKey::from_bytes` now takes an `Option<MgmAlgorithmId>` argument, to
+    disambiguate algorithms with the same key length.
+- `yubikey::piv`:
+  - `ManagementAlgorithmId` has been renamed to `SlotAlgorithmId`, and its
+    `ThreeDes` variant has been replaced by `SlotAlgorithmId::Management`
+    containing a `yubikey::MgmAlgorithmId`.
+- Metadata command returns `Error:NotFound` instead of `Error::GenericError` when the object doesn't exist ([#558]).
+
+### Removed
+- `yubikey::mgm`:
+  - `MgmKey::new` (use `MgmKey::from_bytes(_, Some(MgmAlgorithmId::ThreeDes))`
+    instead).
+  - `impl AsRef<[u8; DES_LEN_3DES]> for MgmKey` (use
+    `impl AsRef<[u8]> for MgmKey` instead).
+  - `impl Default for MgmKey` (use `MgmKey::get_default` instead).
+  - `impl TryFrom<&[u8]> for MgmKey` (use `MgmKey::from_bytes` instead).
+
+## 0.8.0 (2023-08-15)
+### Added
+- `impl Debug for {Context, YubiKey}` ([#457])
+- `YubiKey::disconnect` ([#462])
+- `Error::AppletNotFound` ([#476])

 ### Changed
 - `Reader::open` now returns `Error::AppletNotFound` instead of `Error::Generic`
@@ -18,11 +61,35 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `Reader::open` now avoids resetting the card if an error occurs (equivalent to
  calling `YubiKey::disconnect(pcsc::Disposition::LeaveCard)` if `Reader::open`
  succeeds).
+- Raise minimum `pcsc` version to 2.3.1 and remove workaround ([#478])
+- Bump asymmetric crypto dependencies; MSRV 1.65 ([#490])
+  - `elliptic-curve` v0.13
+  - `k256` v0.13
+  - `p256` v0.13
+  - `p384` v0.13
+  - `pbkdf2` v0.12
+  - `rsa` v0.9 ([#502])
+  - `signature` v2
+- Use `x509-cert` certificate builder ([#495])
+- Make `RsaKeyData::new` fallible ([#517])

 ### Fixed
 - `StatusWords::code` now returns the correct code (including embedded `tries`
  count) for `StatusWords::VerifyFailError`. Previously the returned code lost
  information and was not round-trip compatible with `StatusWords::from(u16)`.
+- Parsing of serial numbers ([#466])
+- Make `YubiKey::open()` more robust ([#504])
+
+[#457]: https://github.com/iqlusioninc/yubikey.rs/pull/457
+[#462]: https://github.com/iqlusioninc/yubikey.rs/pull/462
+[#466]: https://github.com/iqlusioninc/yubikey.rs/pull/466
+[#476]: https://github.com/iqlusioninc/yubikey.rs/pull/476
+[#478]: https://github.com/iqlusioninc/yubikey.rs/pull/478
+[#490]: https://github.com/iqlusioninc/yubikey.rs/pull/490
+[#495]: https://github.com/iqlusioninc/yubikey.rs/pull/495
+[#502]: https://github.com/iqlusioninc/yubikey.rs/pull/502
+[#504]: https://github.com/iqlusioninc/yubikey.rs/pull/504
+[#517]: https://github.com/iqlusioninc/yubikey.rs/pull/517

 ## 0.7.0 (2022-11-14)
 ### Added
@@ -1,10 +1,10 @@
 [package]
 name = "yubikey"
-version = "0.8.0-pre.0"
+version = "0.9.0-pre.0"
 description = """
 Pure Rust cross-platform host-side driver for YubiKey devices from Yubico with
 support for hardware-backed public-key decryption and digital signatures using
-the Personal Identity Verification (PIV) application. Supports RSA (1024/2048)
+the Personal Identity Verification (PIV) application. Supports RSA (1024/2048/3072/4096)
 or ECC (NIST P-256/P-384) algorithms e.g, PKCS#1v1.5, ECDSA
 """
 authors = ["Tony Arcieri <tony@iqlusion.io>", "Yubico AB"]
@@ -14,47 +14,55 @@ readme = "README.md"
 categories = ["api-bindings", "authentication", "cryptography", "hardware-support"]
 keywords = ["ecdsa", "encryption", "rsa", "piv", "signature"]
 edition = "2021"
-rust-version = "1.65"
+rust-version = "1.85"

 [workspace]
 members = [".", "cli"]

+[workspace.dependencies]
+sha2 = "0.11"
+x509-cert = { version = "0.3.0-rc.4", features = ["builder", "hazmat"] }
+
 [dependencies]
-chrono = "0.4.23"
-cookie-factory = "0.3"
-der-parser = "8"
-des = "0.8"
-elliptic-curve = "0.13"
+aes = { version = "0.9.0-rc.4", features = ["zeroize"] }
+bitflags = "2.5.0"
+cipher = { version = "0.5", features = ["getrandom", "rand_core"] }
+curve25519-dalek = "5.0.0-pre.6"
+der = "0.8"
+des = "0.9.0-rc.3"
+ecdsa = { version = "0.17.0-rc.16", features = ["digest", "pem"] }
+ed25519-dalek = { version = "3.0.0-pre.6", features = ["alloc", "pkcs8"] }
+elliptic-curve = "0.14.0-rc.29"
 hex = { package = "base16ct", version = "0.2", features = ["alloc"] }
-hmac = "0.12"
 log = "0.4"
-nom = "7"
-num-bigint-dig = { version = "0.8", features = ["rand"] }
-num-traits = "0.2"
-num-integer = "0.1"
-p256 = "0.13"
-p384 = "0.13"
-pbkdf2 = { version = "0.12", default-features = false, features = ["hmac"] }
+nom = "8"
+p256 = "0.14.0-rc.8"
+p384 = "0.14.0-rc.8"
+pbkdf2 = { version = "0.13.0-rc.10", default-features = false, features = ["hmac"] }
 pcsc = "2.3.1"
-rand_core = { version = "0.6", features = ["std"] }
-rsa = "=0.9.0-pre.0"
-secrecy = "0.8"
-sha1 = { version = "0.10", features = ["oid"] }
-sha2 = { version = "0.10", features = ["oid"] }
+rand = "0.10"
+rand_core = "0.10"
+rsa = { version = "0.10.0-rc.17", features = ["sha2"] }
+sha1 = { version = "0.11", features = ["oid"] }
+sha2 = { workspace = true, features = ["oid"] }
+signature = "3.0.0-rc.10"
 subtle = "2"
 uuid = { version = "1.2", features = ["v4"] }
-x509 = "0.2"
-x509-parser = "0.14"
+x25519-dalek = "3.0.0-pre.6"
+x509-cert.workspace = true
 zeroize = "1"

 [dev-dependencies]
-env_logger = "0.10"
+env_logger = "0.11"
 once_cell = "1"
-signature = "2"

 [features]
 untested = []

+[[example]]
+name = "change-mode"
+required-features = ["untested"]
+
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]
@@ -22,7 +22,7 @@ access provided by the [`pcsc` crate].
 ## About

 YubiKeys are versatile devices and through their PIV support, you can use them
-to store a number of RSA (2048/1024) and ECC (NIST P-256/P-384) private keys
+to store a number of RSA (1024/2048/3072/4096) and ECC (NIST P-256/P-384) private keys
 with configurable access control policies. Both the signing (RSASSA/ECDSA) and
 encryption (PKCS#1v1.5/ECIES) use cases are supported for either key type.

@@ -54,15 +54,19 @@ See [Yubico's guide to PIV-enabled YubiKeys][yk-guide] for more information
 on which devices support PIV and the available functionality.

 ### Supported Algorithms
+
 - **Authentication**: `3DES`
 - **Encryption**:
-  - RSA: `RSA1024`, `RSA2048`
+    - RSA: `RSA1024`, `RSA2048`, `RSA3072`, `RSA4096`
    - ECC: `ECCP256`, `ECCP384` (NIST curves: P-256, P-384)
 - **Signatures**:
-  - RSASSA-PKCS#1v1.5: `RSA1024`, `RSA2048`
+    - RSASSA-PKCS#1v1.5: `RSA1024`, `RSA2048`, `RSA3072`, `RSA4096`
    - ECDSA: `ECCP256`, `ECCP384` (NIST curves: P-256, P-384)

-NOTE: RSASSA-PSS signatures and RSA-OAEP encryption may be supportable (TBD)
+NOTE:
+
+- RSASSA-PSS signatures and RSA-OAEP encryption may be supportable (TBD)
+- `RSA3072` and `RSA4096` require a YubiKey with firmware 5.7 or newer.

 ## Minimum Supported Rust Version

@@ -73,8 +77,7 @@ Rust **1.60** or newer.
 - [YubiKey 4] series
 - [YubiKey 5] series

-NOTE: Nano and USB-C variants of the above are also supported.
-      Pre-YK4 [YubiKey NEO] series is **NOT** supported (see [#18]).
+NOTE: Nano and USB-C variants of the above are also supported. NEO series is NOT supported.

 ## Supported Operating Systems

@@ -102,8 +105,8 @@ We would appreciate any help testing this functionality and removing the

 ## Testing

-To run the full test suite, you'll need a connected YubiKey NEO/4/5 device in
-the default state (i.e. default PIN/PUK).
+To run the full test suite, you'll need a supported YubiKey device connected
+which is in the default state (i.e. default PIN/PUK).

 Tests which run live against a YubiKey device are marked as `#[ignore]` by
 default in order to pass when running in a CI environment. To run these
@@ -172,7 +175,7 @@ Yubico's [yubico-piv-tool], a C library/CLI program. The original library
 was licensed under a [2-Clause BSD License][BSDL], which this library inherits
 as a derived work.

-Copyright (c) 2014-2023 Yubico AB, Tony Arcieri
+Copyright (c) 2014-2025 Yubico AB, Tony Arcieri
 All rights reserved.

 Redistribution and use in source and binary forms, with or without
@@ -208,16 +211,16 @@ or conditions.

 [//]: # (badges)

-[crate-image]:  https://buildstats.info/crate/yubikey
+[crate-image]: https://img.shields.io/crates/v/yubikey?logo=rust
 [crate-link]: https://crates.io/crates/yubikey
 [docs-image]: https://docs.rs/yubikey/badge.svg
 [docs-link]: https://docs.rs/yubikey/
 [license-image]: https://img.shields.io/badge/license-BSD-blue.svg
 [license-link]: https://github.com/iqlusioninc/yubikey.rs/blob/main/COPYING
-[msrv-image]: https://img.shields.io/badge/rustc-1.65+-blue.svg
+[msrv-image]: https://img.shields.io/badge/rustc-1.85+-blue.svg
 [safety-image]: https://img.shields.io/badge/unsafe-forbidden-success.svg
 [safety-link]: https://github.com/rust-secure-code/safety-dance/
-[build-image]: https://github.com/iqlusioninc/yubikey.rs/workflows/CI/badge.svg?branch=main&event=push
+[build-image]: https://github.com/iqlusioninc/yubikey.rs/actions/workflows/ci.yml/badge.svg
 [build-link]: https://github.com/iqlusioninc/yubikey.rs/actions
 [deps-image]: https://deps.rs/repo/github/iqlusioninc/yubikey.rs/status.svg
 [deps-link]: https://deps.rs/repo/github/iqlusioninc/yubikey.rs
@@ -231,10 +234,10 @@ or conditions.
 [PC/SC]: https://en.wikipedia.org/wiki/PC/SC
 [`pcsc` crate]: https://github.com/bluetech/pcsc-rust
 [yk-guide]: https://developers.yubico.com/PIV/Introduction/YubiKey_and_PIV.html
-[YubiKey NEO]: https://support.yubico.com/support/solutions/articles/15000006494-yubikey-neo
 [YubiKey 4]: https://support.yubico.com/support/solutions/articles/15000006486-yubikey-4
 [YubiKey 5]: https://www.yubico.com/products/yubikey-5-overview/
 [yubico-piv-tool]: https://github.com/Yubico/yubico-piv-tool/
+[piv-tool-guide]: https://docs.yubico.com/software/yubikey/tools/pivtool/Introduction.html
 [Corrode]: https://github.com/jameysharp/corrode
 [cc-web]: https://contributor-covenant.org/
 [cc-md]: https://github.com/iqlusioninc/yubikey.rs/blob/main/CODE_OF_CONDUCT.md
@@ -4,6 +4,10 @@ All notable changes to this project 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 [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

+## Unreleased
+### Changed
+- MSRV is now 1.81.
+
 ## 0.7.0 (2022-11-14)
 ### Changed
 - Bump `clap` to v4.0 ([#438])
@@ -1,6 +1,6 @@
 [package]
 name = "yubikey-cli"
-version = "0.7.0"
+version = "0.9.0-pre"
 description = """
 Command-line interface for performing encryption and signing using RSA/ECC keys
 stored on YubiKey devices.
@@ -12,15 +12,15 @@ readme = "README.md"
 categories = ["command-line-utilities", "cryptography", "hardware-support"]
 keywords = ["ecdsa", "rsa", "piv", "pcsc", "yubikey"]
 edition = "2021"
-rust-version = "1.56"
+rust-version = "1.85"

 [dependencies]
 clap = { version = "4", features = ["derive"] }
-env_logger = "0.10"
+env_logger = "0.11"
 hex = { package = "base16ct", version = "0.2", features = ["alloc"] }
 log = "0.4"
 once_cell = "1"
-sha2 = "0.10"
+sha2.workspace = true
 termcolor = "1"
-x509-parser = "0.14"
-yubikey = { version = "0.8.0-pre.0", path = ".." }
+x509-cert.workspace = true
+yubikey = { version = "=0.9.0-pre.0", path = ".." }
@@ -25,8 +25,7 @@ Rust **1.60** or newer.
 - [YubiKey 4] series
 - [YubiKey 5] series

-NOTE: Nano and USB-C variants of the above are also supported.
-      Pre-YK4 [YubiKey NEO] series is **NOT** supported (see [#18]).
+NOTE: Nano and USB-C variants of the above are also supported. NEO series is NOT supported.

 ## Security Warning

@@ -84,7 +83,7 @@ or conditions.
 [docs-image]: https://docs.rs/yubikey-cli/badge.svg
 [docs-link]: https://docs.rs/yubikey-cli/
 [license-image]: https://img.shields.io/badge/license-BSD-blue.svg
-[rustc-image]: https://img.shields.io/badge/rustc-1.60+-blue.svg
+[rustc-image]: https://img.shields.io/badge/rustc-1.85+-blue.svg
 [maintenance-image]: https://img.shields.io/badge/maintenance-experimental-blue.svg
 [safety-image]: https://img.shields.io/badge/unsafe-forbidden-success.svg
 [safety-link]: https://github.com/rust-secure-code/safety-dance/
@@ -98,7 +97,6 @@ or conditions.
 [PIV]: https://piv.idmanagement.gov/
 [yk-guide]: https://developers.yubico.com/PIV/Introduction/YubiKey_and_PIV.html
 [Yubico]: https://www.yubico.com/
-[YubiKey NEO]: https://support.yubico.com/support/solutions/articles/15000006494-yubikey-neo
 [YubiKey 4]: https://support.yubico.com/support/solutions/articles/15000006486-yubikey-4
 [YubiKey 5]: https://www.yubico.com/products/yubikey-5-overview/
 [yubico-piv-tool]: https://github.com/Yubico/yubico-piv-tool/
@@ -9,7 +9,7 @@ use std::{
    sync::Mutex,
 };
 use termcolor::{Color, ColorChoice, ColorSpec, StandardStream, StandardStreamLock, WriteColor};
-use x509_parser::parse_x509_certificate;
+use x509_cert::der::Encode;
 use yubikey::{certificate::Certificate, piv::*, YubiKey};

 /// Print a success status message (in green if colors are enabled)
@@ -180,52 +180,37 @@ pub fn print_cert_info(
            return Ok(());
        }
    };
-    let buf = cert.into_buffer();
+    let cert = &cert.cert;

-    if !buf.is_empty() {
-        let fingerprint = Sha256::digest(&buf);
+    let fingerprint = Sha256::digest(cert.to_der().unwrap());
    let slot_id: u8 = slot.into();
    print_cert_attr(stream, "Slot", format!("{:x}", slot_id))?;
-        match parse_x509_certificate(&buf) {
-            Ok((_rem, cert)) => {
    print_cert_attr(
        stream,
        "Algorithm",
-                    cert.tbs_certificate.subject_pki.algorithm.algorithm,
+        cert.tbs_certificate()
+            .subject_public_key_info()
+            .algorithm
+            .oid,
    )?;

-                print_cert_attr(stream, "Subject", cert.tbs_certificate.subject)?;
-                print_cert_attr(stream, "Issuer", cert.tbs_certificate.issuer)?;
+    print_cert_attr(stream, "Subject", cert.tbs_certificate().subject())?;
+    print_cert_attr(stream, "Issuer", cert.tbs_certificate().issuer())?;
    print_cert_attr(
        stream,
        "Fingerprint",
-                    &hex::upper::encode_string(&fingerprint),
+        hex::upper::encode_string(&fingerprint),
    )?;
    print_cert_attr(
        stream,
        "Not Before",
-                    cert.tbs_certificate
-                        .validity
-                        .not_before
-                        .to_rfc2822()
-                        .unwrap(),
+        cert.tbs_certificate().validity().not_before,
    )?;
    print_cert_attr(
        stream,
        "Not After",
-                    cert.tbs_certificate
-                        .validity
-                        .not_after
-                        .to_rfc2822()
-                        .unwrap(),
+        cert.tbs_certificate().validity().not_after,
    )?;
-            }
-            _ => {
-                println!("Failed to parse certificate");
-                return Ok(());
-            }
-        };
-    }

    Ok(())
 }
@@ -0,0 +1,10 @@
+#![cfg(feature = "untested")]
+
+use yubikey::{mgm, YubiKey};
+
+fn main() {
+    let yubikey = YubiKey::open().unwrap();
+
+    let mut mgmt = mgm::Manager::new(yubikey).unwrap();
+    mgmt.enable_yubihsm().unwrap();
+}
@@ -82,6 +82,12 @@ impl Apdu {
        self
    }

+    /// Set this APDU's second parameter only
+    pub(crate) fn p2(&mut self, value: u8) -> &mut Self {
+        self.p2 = value;
+        self
+    }
+
    /// Set both parameters for this APDU
    pub fn params(&mut self, p1: u8, p2: u8) -> &mut Self {
        self.p1 = p1;
@@ -198,6 +204,15 @@ pub enum Ins {
    /// Get slot metadata
    GetMetadata,

+    /// Management // Read Config
+    ReadConfig,
+
+    /// Management // Write Config
+    WriteConfig,
+
+    /// Management // DeviceReset
+    DeviceReset,
+
    /// Other/unrecognized instruction codes
    Other(u8),
 }
@@ -223,6 +238,12 @@ impl Ins {
            Ins::Attest => 0xf9,
            Ins::GetSerial => 0xf8,
            Ins::GetMetadata => 0xf7,
+
+            // Management
+            Ins::ReadConfig => 0x1d,
+            Ins::WriteConfig => 0x1c,
+            Ins::DeviceReset => 0x1f,
+
            Ins::Other(code) => code,
        }
    }
@@ -231,6 +252,11 @@ impl Ins {
 impl From<u8> for Ins {
    fn from(code: u8) -> Self {
        match code {
+            // Management
+            0x1d => Ins::ReadConfig,
+            0x1c => Ins::WriteConfig,
+            0x1f => Ins::DeviceReset,
+
            0x20 => Ins::Verify,
            0x24 => Ins::ChangeReference,
            0x2c => Ins::ResetRetry,
@@ -318,7 +344,7 @@ impl From<Vec<u8>> for Response {
        }

        let sw = StatusWords::from(
-            (bytes[bytes.len() - 2] as u16) << 8 | (bytes[bytes.len() - 1] as u16),
+            ((bytes[bytes.len() - 2] as u16) << 8) | (bytes[bytes.len() - 1] as u16),
        );

        let len = bytes.len() - 2;
@@ -395,6 +421,9 @@ pub(crate) enum StatusWords {
    /// Not enough memory
    NoSpaceError,

+    /// Referenced data or reference data not found
+    ReferenceDataNotFoundError,
+
    //
    // Custom Yubico Status Word extensions
    //
@@ -428,6 +457,7 @@ impl StatusWords {
            StatusWords::IncorrectParamError => 0x6a80,
            StatusWords::NotFoundError => 0x6a82,
            StatusWords::NoSpaceError => 0x6a84,
+            StatusWords::ReferenceDataNotFoundError => 0x6a88,
            StatusWords::IncorrectSlotError => 0x6b00,
            StatusWords::NotSupportedError => 0x6d00,
            StatusWords::CommandAbortedError => 0x6f00,
@@ -462,6 +492,7 @@ impl From<u16> for StatusWords {
            0x6a80 => StatusWords::IncorrectParamError,
            0x6a82 => StatusWords::NotFoundError,
            0x6a84 => StatusWords::NoSpaceError,
+            0x6a88 => StatusWords::ReferenceDataNotFoundError,
            0x6b00 => StatusWords::IncorrectSlotError,
            0x6d00 => StatusWords::NotSupportedError,
            0x6f00 => StatusWords::CommandAbortedError,
@@ -30,8 +30,9 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

-use crate::{Error, Result, YubiKey};
-use rand_core::{OsRng, RngCore};
+use crate::{Result, YubiKey};
+use cipher::common::Generate;
+use rand_core::CryptoRng;
 use std::fmt::{self, Debug, Display};

 /// CCCID offset
@@ -48,6 +49,7 @@ const OBJ_CAPABILITY: u32 = 0x005f_c107;
 ///  - 0xff == Manufacturer ID (dummy)
 ///  - 0x02 == Card type (javaCard)
 ///  - next 14 bytes: card ID
+#[allow(dead_code)]
 const CCC_TMPL: &[u8] = &[
    0xf0, 0x15, 0xa0, 0x00, 0x00, 0x01, 0x16, 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf1, 0x01, 0x21, 0xf2, 0x01, 0x21, 0xf3, 0x00, 0xf4,
@@ -65,9 +67,12 @@ impl CardId {

    /// Generate a random CCC Card ID
    pub fn generate() -> Self {
-        let mut id = [0u8; Self::BYTE_SIZE];
-        OsRng.fill_bytes(&mut id);
-        Self(id)
+        Self(Generate::generate())
+    }
+
+    /// Generate a random CCC Card ID from an [`Rng`]
+    pub fn generate_from_rng<R: CryptoRng + ?Sized>(rng: &mut R) -> Self {
+        Self(Generate::generate_from_rng(rng))
    }
 }

@@ -90,17 +95,11 @@ impl CccId {
    pub fn get(yubikey: &mut YubiKey) -> Result<Self> {
        let txn = yubikey.begin_transaction()?;
        let response = txn.fetch_object(OBJ_CAPABILITY)?;
-
-        if response.len() != CCC_TMPL.len() {
-            return Err(Error::GenericError);
-        }
-
-        Ok(Self(response[..Self::BYTE_SIZE].try_into().unwrap()))
+        Ok(response[..Self::BYTE_SIZE].try_into().map(Self)?)
    }

    /// Set Cardholder Capability Container (CCC) ID
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn set(&self, yubikey: &mut YubiKey) -> Result<()> {
        let mut buf = CCC_TMPL.to_vec();
        buf[0..self.0.len()].copy_from_slice(&self.0);
@@ -33,90 +33,27 @@
 use crate::{
    consts::CB_OBJ_MAX,
    error::{Error, Result},
-    piv::{sign_data, AlgorithmId, SlotId},
+    piv::SlotId,
    serialization::*,
    transaction::Transaction,
    yubikey::YubiKey,
    Buffer,
 };
-use chrono::{DateTime, Utc};
-use elliptic_curve::sec1::EncodedPoint as EcPublicKey;
 use log::error;
-use num_bigint_dig::BigUint;
-use p256::NistP256;
-use p384::NistP384;
-use rsa::{PublicKeyParts, RsaPublicKey};
-use sha2::{Digest, Sha256};
-use std::fmt::Display;
-use std::{fmt, ops::DerefMut};
-use x509::{der::Oid, RelativeDistinguishedName};
-use x509_parser::{parse_x509_certificate, x509::SubjectPublicKeyInfo};
+use x509_cert::{
+    builder::{profile::BuilderProfile, Builder, CertificateBuilder},
+    der::{referenced::OwnedToRef, Decode, Encode},
+    name::Name,
+    serial_number::SerialNumber,
+    spki::{SubjectPublicKeyInfoOwned, SubjectPublicKeyInfoRef},
+    time::Validity,
+};
 use zeroize::Zeroizing;

-// TODO: Make these der_parser::oid::Oid constants when it has const fn support.
-const OID_RSA_ENCRYPTION: &str = "1.2.840.113549.1.1.1";
-const OID_EC_PUBLIC_KEY: &str = "1.2.840.10045.2.1";
-const OID_NIST_P256: &str = "1.2.840.10045.3.1.7";
-const OID_NIST_P384: &str = "1.3.132.0.34";
-
 const TAG_CERT: u8 = 0x70;
 const TAG_CERT_COMPRESS: u8 = 0x71;
 const TAG_CERT_LRC: u8 = 0xFE;

-/// A serial number for a [`Certificate`].
-#[derive(Clone, Debug)]
-pub struct Serial(BigUint);
-
-impl From<BigUint> for Serial {
-    fn from(num: BigUint) -> Serial {
-        Serial(num)
-    }
-}
-
-impl From<[u8; 20]> for Serial {
-    fn from(bytes: [u8; 20]) -> Serial {
-        Serial(BigUint::from_bytes_be(&bytes))
-    }
-}
-
-impl TryFrom<&[u8]> for Serial {
-    type Error = Error;
-
-    fn try_from(bytes: &[u8]) -> Result<Serial> {
-        if bytes.len() <= 20 {
-            Ok(Serial(BigUint::from_bytes_be(bytes)))
-        } else {
-            Err(Error::ParseError)
-        }
-    }
-}
-
-impl Serial {
-    fn to_bytes(&self) -> Vec<u8> {
-        self.0.to_bytes_be()
-    }
-    /// Returns itself formatted as x509 compatible hex string
-    pub fn as_x509_hex(&self) -> String {
-        let data = self.to_bytes();
-        let raw_hex_string = format!("{:02X?}", data);
-        raw_hex_string
-            .replace(", ", ":")
-            .replace([']', '['], "")
-            .to_lowercase()
-    }
-    /// Returns itself formatted as x509 compatible int string
-    pub fn as_x509_int(&self) -> String {
-        let Serial(buint) = self;
-        format!("{}", buint)
-    }
-}
-
-impl Display for Serial {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str(&self.as_x509_hex())
-    }
-}
-
 /// Information about how a [`Certificate`] is stored within a YubiKey.
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub enum CertInfo {
@@ -148,210 +85,11 @@ impl From<CertInfo> for u8 {
    }
 }

-impl x509::AlgorithmIdentifier for AlgorithmId {
-    type AlgorithmOid = &'static [u64];
-
-    fn algorithm(&self) -> Self::AlgorithmOid {
-        match self {
-            // RSA encryption
-            AlgorithmId::Rsa1024 | AlgorithmId::Rsa2048 => &[1, 2, 840, 113_549, 1, 1, 1],
-            // EC Public Key
-            AlgorithmId::EccP256 | AlgorithmId::EccP384 => &[1, 2, 840, 10045, 2, 1],
-        }
-    }
-
-    fn parameters<W: std::io::Write>(
-        &self,
-        w: cookie_factory::WriteContext<W>,
-    ) -> cookie_factory::GenResult<W> {
-        use x509::der::write::der_oid;
-
-        // From [RFC 5480](https://tools.ietf.org/html/rfc5480#section-2.1.1):
-        // ```text
-        // ECParameters ::= CHOICE {
-        //   namedCurve         OBJECT IDENTIFIER
-        //   -- implicitCurve   NULL
-        //   -- specifiedCurve  SpecifiedECDomain
-        // }
-        // ```
-        match self {
-            AlgorithmId::EccP256 => der_oid(&[1, 2, 840, 10045, 3, 1, 7][..])(w),
-            AlgorithmId::EccP384 => der_oid(&[1, 3, 132, 0, 34][..])(w),
-            _ => Ok(w),
-        }
-    }
-}
-
-/// Information about a public key within a [`Certificate`].
-#[derive(Clone, Eq, PartialEq)]
-pub enum PublicKeyInfo {
-    /// RSA keys
-    Rsa {
-        /// RSA algorithm
-        algorithm: AlgorithmId,
-
-        /// Public key
-        pubkey: RsaPublicKey,
-    },
-
-    /// EC P-256 keys
-    EcP256(EcPublicKey<NistP256>),
-
-    /// EC P-384 keys
-    EcP384(EcPublicKey<NistP384>),
-}
-
-impl fmt::Debug for PublicKeyInfo {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "PublicKeyInfo({:?})", self.algorithm())
-    }
-}
-
-impl PublicKeyInfo {
-    fn parse(subject_pki: &SubjectPublicKeyInfo<'_>) -> Result<Self> {
-        match subject_pki.algorithm.algorithm.to_string().as_str() {
-            OID_RSA_ENCRYPTION => {
-                let pubkey = read_pki::rsa_pubkey(&subject_pki.subject_public_key.data)?;
-
-                Ok(PublicKeyInfo::Rsa {
-                    algorithm: match pubkey.n().bits() {
-                        1024 => AlgorithmId::Rsa1024,
-                        2048 => AlgorithmId::Rsa2048,
-                        _ => return Err(Error::AlgorithmError),
-                    },
-                    pubkey,
-                })
-            }
-            OID_EC_PUBLIC_KEY => {
-                let key_bytes = &subject_pki.subject_public_key.data;
-                let algorithm_parameters = subject_pki
-                    .algorithm
-                    .parameters
-                    .as_ref()
-                    .ok_or(Error::InvalidObject)?;
-
-                match read_pki::ec_parameters(algorithm_parameters)? {
-                    AlgorithmId::EccP256 => EcPublicKey::<NistP256>::from_bytes(key_bytes)
-                        .map(PublicKeyInfo::EcP256)
-                        .map_err(|_| Error::InvalidObject),
-                    AlgorithmId::EccP384 => EcPublicKey::<NistP384>::from_bytes(key_bytes)
-                        .map(PublicKeyInfo::EcP384)
-                        .map_err(|_| Error::InvalidObject),
-                    _ => Err(Error::AlgorithmError),
-                }
-            }
-            _ => Err(Error::InvalidObject),
-        }
-    }
-
-    /// Returns the algorithm that this public key can be used with.
-    pub fn algorithm(&self) -> AlgorithmId {
-        match self {
-            PublicKeyInfo::Rsa { algorithm, .. } => *algorithm,
-            PublicKeyInfo::EcP256(_) => AlgorithmId::EccP256,
-            PublicKeyInfo::EcP384(_) => AlgorithmId::EccP384,
-        }
-    }
-}
-
-impl x509::SubjectPublicKeyInfo for PublicKeyInfo {
-    type AlgorithmId = AlgorithmId;
-    type SubjectPublicKey = Vec<u8>;
-
-    fn algorithm_id(&self) -> AlgorithmId {
-        self.algorithm()
-    }
-
-    fn public_key(&self) -> Vec<u8> {
-        match self {
-            PublicKeyInfo::Rsa { pubkey, .. } => {
-                cookie_factory::gen_simple(write_pki::rsa_pubkey(pubkey), vec![])
-                    .expect("can write to Vec")
-            }
-            PublicKeyInfo::EcP256(pubkey) => pubkey.as_bytes().to_vec(),
-            PublicKeyInfo::EcP384(pubkey) => pubkey.as_bytes().to_vec(),
-        }
-    }
-}
-
-/// Digest algorithms.
-///
-/// See RFC 4055 and RFC 8017.
-enum DigestId {
-    /// Secure Hash Algorithm 256 (SHA256)
-    Sha256,
-}
-
-impl x509::AlgorithmIdentifier for DigestId {
-    type AlgorithmOid = &'static [u64];
-
-    fn algorithm(&self) -> Self::AlgorithmOid {
-        match self {
-            // See https://tools.ietf.org/html/rfc4055#section-2.1
-            DigestId::Sha256 => &[2, 16, 840, 1, 101, 3, 4, 2, 1],
-        }
-    }
-
-    fn parameters<W: std::io::Write>(
-        &self,
-        w: cookie_factory::WriteContext<W>,
-    ) -> cookie_factory::GenResult<W> {
-        // Parameters are an explicit NULL
-        // See https://tools.ietf.org/html/rfc8017#appendix-A.2.4
-        x509::der::write::der_null()(w)
-    }
-}
-
-enum SignatureId {
-    /// Public-Key Cryptography Standards (PKCS) #1 version 1.5 signature algorithm with
-    /// Secure Hash Algorithm 256 (SHA256) and Rivest, Shamir and Adleman (RSA) encryption
-    ///
-    /// See RFC 4055 and RFC 8017.
-    Sha256WithRsaEncryption,
-
-    /// Elliptic Curve Digital Signature Algorithm (DSA) coupled with the Secure Hash
-    /// Algorithm 256 (SHA256) algorithm
-    ///
-    /// See RFC 5758.
-    EcdsaWithSha256,
-}
-
-impl x509::AlgorithmIdentifier for SignatureId {
-    type AlgorithmOid = &'static [u64];
-
-    fn algorithm(&self) -> Self::AlgorithmOid {
-        match self {
-            SignatureId::Sha256WithRsaEncryption => &[1, 2, 840, 113_549, 1, 1, 11],
-            SignatureId::EcdsaWithSha256 => &[1, 2, 840, 10045, 4, 3, 2],
-        }
-    }
-
-    fn parameters<W: std::io::Write>(
-        &self,
-        w: cookie_factory::WriteContext<W>,
-    ) -> cookie_factory::GenResult<W> {
-        // No parameters for any SignatureId
-        Ok(w)
-    }
-}
-
 /// Certificates
 #[derive(Clone, Debug)]
 pub struct Certificate {
-    serial: Serial,
-    #[allow(dead_code)]
-    issuer: String,
-    subject: String,
-    subject_pki: PublicKeyInfo,
-    data: Buffer,
-}
-
-impl<'a> TryFrom<&'a [u8]> for Certificate {
-    type Error = Error;
-
-    fn try_from(bytes: &'a [u8]) -> Result<Self> {
-        Self::from_bytes(bytes.to_vec())
-    }
+    /// Inner certificate
+    pub cert: x509_cert::Certificate,
 }

 impl Certificate {
@@ -360,112 +98,30 @@ impl Certificate {
    ///
    /// `extensions` is optional; if empty, no extensions will be included. Due to the
    /// need for an `O: Oid` type parameter, users who do not have any extensions should
-    /// use the workaround `let extensions: &[x509::Extension<'_, &[u64]>] = &[];`.
-    pub fn generate_self_signed<O: Oid>(
+    /// use the workaround `let extensions: &[x509_cert::Extension<'_, &[u64]>] = &[];`.
+    pub fn generate_self_signed<F, KT: yubikey_signer::KeyType>(
        yubikey: &mut YubiKey,
        key: SlotId,
-        serial: impl Into<Serial>,
-        not_after: Option<DateTime<Utc>>,
-        subject: &[RelativeDistinguishedName<'_>],
-        subject_pki: PublicKeyInfo,
-        extensions: &[x509::Extension<'_, O>],
-    ) -> Result<Self> {
-        let serial = serial.into();
+        serial: SerialNumber,
+        validity: Validity,
+        subject: Name,
+        subject_pki: SubjectPublicKeyInfoOwned,
+        extensions: F,
+    ) -> Result<Self>
+    where
+        F: FnOnce(&mut CertificateBuilder<SelfSigned>) -> der::Result<()>,
+    {
+        let signer =
+            yubikey_signer::Signer::<'_, KT>::new(yubikey, key, subject_pki.owned_to_ref())?;
+        let mut builder =
+            CertificateBuilder::new(SelfSigned { subject }, serial, validity, subject_pki)
+                .map_err(|_| Error::KeyError)?;

-        let mut tbs_cert = Buffer::new(Vec::with_capacity(CB_OBJ_MAX));
-
-        let signature_algorithm = match subject_pki.algorithm() {
-            AlgorithmId::Rsa1024 | AlgorithmId::Rsa2048 => SignatureId::Sha256WithRsaEncryption,
-            AlgorithmId::EccP256 | AlgorithmId::EccP384 => SignatureId::EcdsaWithSha256,
-        };
-
-        cookie_factory::gen(
-            x509::write::tbs_certificate(
-                &serial.to_bytes(),
-                &signature_algorithm,
-                // Issuer and subject are the same in self-signed certificates.
-                subject,
-                Utc::now(),
-                not_after,
-                subject,
-                &subject_pki,
-                extensions,
-            ),
-            tbs_cert.deref_mut(),
-        )
-        .expect("can serialize to Vec");
-
-        let signature = match signature_algorithm {
-            SignatureId::Sha256WithRsaEncryption => {
-                use cookie_factory::{combinator::slice, sequence::tuple};
-                use x509::{
-                    der::write::{der_octet_string, der_sequence},
-                    write::algorithm_identifier,
-                };
-
-                let em_len = if let AlgorithmId::Rsa1024 = subject_pki.algorithm() {
-                    128
-                } else {
-                    256
-                };
-
-                let h = Sha256::digest(&tbs_cert);
-
-                let t = cookie_factory::gen_simple(
-                    der_sequence((
-                        algorithm_identifier(&DigestId::Sha256),
-                        der_octet_string(&h),
-                    )),
-                    vec![],
-                )
-                .expect("can serialize into Vec");
-
-                let em = cookie_factory::gen_simple(
-                    tuple((
-                        slice(&[0x00, 0x01]),
-                        slice(&vec![0xff; em_len - t.len() - 3]),
-                        slice(&[0x00]),
-                        slice(t),
-                    )),
-                    vec![],
-                )
-                .expect("can serialize to Vec");
-
-                sign_data(yubikey, &em, subject_pki.algorithm(), key)
-            }
-            SignatureId::EcdsaWithSha256 => sign_data(
-                yubikey,
-                &Sha256::digest(&tbs_cert),
-                subject_pki.algorithm(),
-                key,
-            ),
-        }?;
-
-        let mut data = Buffer::new(Vec::with_capacity(CB_OBJ_MAX));
-
-        cookie_factory::gen(
-            x509::write::certificate(&tbs_cert, &signature_algorithm, &signature),
-            data.deref_mut(),
-        )
-        .expect("can serialize to Vec");
-
-        let (issuer, subject) = parse_x509_certificate(&data)
-            .map(|(_, cert)| {
-                (
-                    cert.tbs_certificate.issuer.to_string(),
-                    cert.tbs_certificate.subject.to_string(),
-                )
-            })
-            .expect("We just serialized this correctly");
-
-        let cert = Certificate {
-            serial,
-            issuer,
-            subject,
-            subject_pki,
-            data,
-        };
+        // Add custom extensions
+        extensions(&mut builder)?;

+        let cert = builder.build(&signer).map_err(|_| Error::KeyError)?;
+        let cert = Self { cert };
        cert.write(yubikey, key, CertInfo::Uncompressed)?;

        Ok(cert)
@@ -480,18 +136,18 @@ impl Certificate {
            return Err(Error::InvalidObject);
        }

-        Certificate::from_bytes(buf)
+        Self::from_bytes(buf)
    }

    /// Write this certificate into the YubiKey in the given slot
    pub fn write(&self, yubikey: &mut YubiKey, slot: SlotId, certinfo: CertInfo) -> Result<()> {
        let txn = yubikey.begin_transaction()?;
-        write_certificate(&txn, slot, Some(&self.data), certinfo)
+        let data = self.cert.to_der().map_err(|_| Error::InvalidObject)?;
+        write_certificate(&txn, slot, Some(&data), certinfo)
    }

    /// Delete a certificate located at the given slot of the given YubiKey
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn delete(yubikey: &mut YubiKey, slot: SlotId) -> Result<()> {
        let txn = yubikey.begin_transaction()?;
        write_certificate(&txn, slot, None, CertInfo::Uncompressed)
@@ -506,55 +162,59 @@ impl Certificate {
            return Err(Error::SizeError);
        }

-        let parsed_cert = match parse_x509_certificate(&cert) {
-            Ok((_, cert)) => cert,
-            _ => return Err(Error::InvalidObject),
-        };
-
-        let serial = Serial::try_from(parsed_cert.tbs_certificate.serial.to_bytes_be().as_slice())
-            .map_err(|_| Error::InvalidObject)?;
-        let issuer = parsed_cert.tbs_certificate.issuer.to_string();
-        let subject = parsed_cert.tbs_certificate.subject.to_string();
-        let subject_pki = PublicKeyInfo::parse(&parsed_cert.tbs_certificate.subject_pki)?;
-
-        Ok(Certificate {
-            serial,
-            issuer,
-            subject,
-            subject_pki,
-            data: cert,
-        })
-    }
-
-    /// Returns the serial number of the certificate.
-    pub fn serial(&self) -> &Serial {
-        &self.serial
+        x509_cert::Certificate::from_der(&cert)
+            .map(|cert| Self { cert })
+            .map_err(|_| Error::InvalidObject)
    }

    /// Returns the Issuer field of the certificate.
-    pub fn issuer(&self) -> &str {
-        &self.issuer
+    pub fn issuer(&self) -> String {
+        self.cert.tbs_certificate().issuer().to_string()
    }

    /// Returns the SubjectName field of the certificate.
-    pub fn subject(&self) -> &str {
-        &self.subject
+    pub fn subject(&self) -> String {
+        self.cert.tbs_certificate().subject().to_string()
    }

    /// Returns the SubjectPublicKeyInfo field of the certificate.
-    pub fn subject_pki(&self) -> &PublicKeyInfo {
-        &self.subject_pki
-    }
-
-    /// Extract the inner buffer
-    pub fn into_buffer(self) -> Buffer {
-        self.data
+    pub fn subject_pki(&self) -> SubjectPublicKeyInfoRef<'_> {
+        self.cert
+            .tbs_certificate()
+            .subject_public_key_info()
+            .owned_to_ref()
    }
 }

-impl AsRef<[u8]> for Certificate {
-    fn as_ref(&self) -> &[u8] {
-        self.data.as_ref()
+/// A [`BuilderProfile`] for self-signed certificates.
+///
+/// This profile has no default extensions.
+pub struct SelfSigned {
+    subject: Name,
+}
+
+impl BuilderProfile for SelfSigned {
+    fn get_issuer(&self, subject: &Name) -> Name {
+        // RFC 5280 Section 3.2:
+        //
+        // > Self-issued certificates are CA certificates in which the issuer and subject
+        // > are the same entity. [..] Self-signed certificates are self-issued
+        // > certificates where the digital signature may be verified by the public key
+        // > bound into the certificate.
+        subject.clone()
+    }
+
+    fn get_subject(&self) -> Name {
+        self.subject.clone()
+    }
+
+    fn build_extensions(
+        &self,
+        _spk: SubjectPublicKeyInfoRef<'_>,
+        _issuer_spk: SubjectPublicKeyInfoRef<'_>,
+        _tbs: &x509_cert::TbsCertificate,
+    ) -> x509_cert::builder::Result<Vec<x509_cert::ext::Extension>> {
+        Ok(vec![])
    }
 }

@@ -590,12 +250,7 @@ pub(crate) fn write_certificate(
 ) -> Result<()> {
    let object_id = slot.object_id();

-    if data.is_none() {
-        return txn.save_object(object_id, &[]);
-    }
-
-    let data = data.unwrap();
-
+    if let Some(data) = data {
        let mut buf = [0u8; CB_OBJ_MAX];
        let mut offset = Tlv::write(&mut buf, TAG_CERT, data)?;

@@ -604,99 +259,260 @@ pub(crate) fn write_certificate(
        offset += Tlv::write(&mut buf[offset..], TAG_CERT_LRC, &[])?;

        txn.save_object(object_id, &buf[..offset])
+    } else {
+        txn.save_object(object_id, &[])
+    }
 }

-mod read_pki {
-    use der_parser::{
-        asn1_rs::Any,
-        ber::BerObjectContent,
-        der::{parse_der_integer, parse_der_sequence_defined_g, DerObject},
-        error::BerError,
+pub mod yubikey_signer {
+    //! Signer implementation for yubikey
+
+    use crate::{
+        error::{Error, Result},
+        piv::AlgorithmId,
+        piv::{sign_data, SlotId},
+        YubiKey,
    };
-    use nom::{combinator, sequence::pair, IResult};
-    use rsa::{BigUint, RsaPublicKey};
-
-    use super::{OID_NIST_P256, OID_NIST_P384};
-    use crate::{piv::AlgorithmId, Error, Result};
-
-    /// From [RFC 8017](https://tools.ietf.org/html/rfc8017#appendix-A.1.1):
-    /// ```text
-    /// RSAPublicKey ::= SEQUENCE {
-    ///     modulus           INTEGER,  -- n
-    ///     publicExponent    INTEGER   -- e
-    /// }
-    /// ```
-    pub(super) fn rsa_pubkey(encoded: &[u8]) -> Result<RsaPublicKey> {
-        fn parse_rsa_pubkey(i: &[u8]) -> IResult<&[u8], (DerObject<'_>, DerObject<'_>), BerError> {
-            parse_der_sequence_defined_g(|i, _| pair(parse_der_integer, parse_der_integer)(i))(i)
-        }
-
-        fn rsa_pubkey_parts(i: &[u8]) -> IResult<&[u8], (BigUint, BigUint), BerError> {
-            combinator::map(parse_rsa_pubkey, |(modulus, public_exponent)| {
-                let n = match modulus.content {
-                    BerObjectContent::Integer(s) => BigUint::from_bytes_be(s),
-                    _ => panic!("expected DER integer"),
+    use der::{
+        asn1::{Any, OctetString},
+        oid::db::rfc5912,
+        Encode, Sequence,
    };
-                let e = match public_exponent.content {
-                    BerObjectContent::Integer(s) => BigUint::from_bytes_be(s),
-                    _ => panic!("expected DER integer"),
+    use sha2::{Digest, Sha256, Sha384, Sha512};
+    use signature::Keypair;
+    use std::{cell::RefCell, fmt, io::Write, marker::PhantomData};
+    use x509_cert::spki::{
+        self, AlgorithmIdentifierOwned, DynSignatureAlgorithmIdentifier, EncodePublicKey,
+        SignatureBitStringEncoding, SubjectPublicKeyInfoRef,
    };

-                (n, e)
-            })(i)
+    type SigResult<T> = core::result::Result<T, signature::Error>;
+
+    /// Key to be used to sign certificates
+    pub trait KeyType {
+        /// Error returned when working with signature
+        type Error: Into<signature::Error> + fmt::Debug;
+        /// The signature type returned by the signer
+        type Signature: SignatureBitStringEncoding
+            + for<'s> TryFrom<&'s [u8], Error = Self::Error>
+            + fmt::Debug;
+        /// The public key used to verify signature
+        type VerifyingKey: EncodePublicKey
+            + DynSignatureAlgorithmIdentifier
+            + Clone
+            + From<Self::PublicKey>;
+        /// Public key type used to load the SPKI formatted key
+        type PublicKey: for<'a> TryFrom<SubjectPublicKeyInfoRef<'a>, Error = spki::Error>;
+
+        /// The algorithm used when talking with the yubikey
+        const ALGORITHM: AlgorithmId;
+
+        /// Prepare buffer before submitting it for signature
+        fn prepare(input: &[u8]) -> SigResult<Vec<u8>>;
+        /// Read back the signature from the device
+        fn read_signature(input: &[u8]) -> SigResult<Self::Signature>;
    }

-        let (n, e) = match rsa_pubkey_parts(encoded) {
-            Ok((_, res)) => res,
-            _ => return Err(Error::InvalidObject),
+    impl KeyType for ed25519_dalek::SigningKey {
+        const ALGORITHM: AlgorithmId = AlgorithmId::Ed25519;
+        type Error = ed25519_dalek::SignatureError;
+        type Signature = ed25519_dalek::Signature;
+        type VerifyingKey = ed25519_dalek::VerifyingKey;
+        type PublicKey = ed25519_dalek::VerifyingKey;
+
+        fn prepare(input: &[u8]) -> SigResult<Vec<u8>> {
+            Ok(Sha512::digest(input).to_vec())
+        }
+
+        fn read_signature(input: &[u8]) -> SigResult<Self::Signature> {
+            Self::Signature::try_from(input)
+        }
+    }
+
+    impl KeyType for p256::NistP256 {
+        const ALGORITHM: AlgorithmId = AlgorithmId::EccP256;
+        type Error = ecdsa::Error;
+        type Signature = p256::ecdsa::DerSignature;
+        type VerifyingKey = p256::ecdsa::VerifyingKey;
+        type PublicKey = p256::ecdsa::VerifyingKey;
+
+        fn prepare(input: &[u8]) -> SigResult<Vec<u8>> {
+            Ok(Sha256::digest(input).to_vec())
+        }
+
+        fn read_signature(input: &[u8]) -> SigResult<Self::Signature> {
+            Self::Signature::from_bytes(input)
+        }
+    }
+
+    impl KeyType for p384::NistP384 {
+        const ALGORITHM: AlgorithmId = AlgorithmId::EccP384;
+        type Error = ecdsa::Error;
+        type Signature = p384::ecdsa::DerSignature;
+        type VerifyingKey = p384::ecdsa::VerifyingKey;
+        type PublicKey = p384::ecdsa::VerifyingKey;
+
+        fn prepare(input: &[u8]) -> SigResult<Vec<u8>> {
+            Ok(Sha384::digest(input).to_vec())
+        }
+
+        fn read_signature(input: &[u8]) -> SigResult<Self::Signature> {
+            Self::Signature::from_bytes(input)
+        }
+    }
+
+    /// Trait used to handle subtypes of RSA keys
+    pub trait RsaLength {
+        /// The length of the RSA key in bits
+        const BIT_LENGTH: usize;
+        /// The algorithm to use when talking with the Yubikey.
+        const ALGORITHM: AlgorithmId;
+    }
+
+    /// RSA 1024 bits key
+    pub struct Rsa1024;
+
+    impl RsaLength for Rsa1024 {
+        const BIT_LENGTH: usize = 1024;
+        const ALGORITHM: AlgorithmId = AlgorithmId::Rsa1024;
+    }
+
+    /// RSA 2048 bits key
+    pub struct Rsa2048;
+
+    impl RsaLength for Rsa2048 {
+        const BIT_LENGTH: usize = 2048;
+        const ALGORITHM: AlgorithmId = AlgorithmId::Rsa2048;
+    }
+
+    /// RSA 3072 bits key
+    pub struct Rsa3072;
+
+    impl RsaLength for Rsa3072 {
+        const BIT_LENGTH: usize = 3072;
+        const ALGORITHM: AlgorithmId = AlgorithmId::Rsa3072;
+    }
+
+    /// RSA 4096 bits key
+    pub struct Rsa4096;
+
+    impl RsaLength for Rsa4096 {
+        const BIT_LENGTH: usize = 4096;
+        const ALGORITHM: AlgorithmId = AlgorithmId::Rsa4096;
+    }
+
+    /// RSA keys used to sign certificates
+    pub struct YubiRsa<N: RsaLength> {
+        _len: PhantomData<N>,
+    }
+
+    impl<N: RsaLength> KeyType for YubiRsa<N> {
+        type Error = signature::Error;
+        type Signature = rsa::pkcs1v15::Signature;
+        type VerifyingKey = rsa::pkcs1v15::VerifyingKey<Sha256>;
+        type PublicKey = rsa::RsaPublicKey;
+        const ALGORITHM: AlgorithmId = N::ALGORITHM;
+
+        fn prepare(input: &[u8]) -> SigResult<Vec<u8>> {
+            let hashed = Sha256::digest(input).to_vec();
+
+            OctetString::new(hashed)
+                .map_err(|e| e.into())
+                .and_then(Self::emsa_pkcs1_1_5)
+                .map_err(signature::Error::from_source)
+        }
+
+        fn read_signature(input: &[u8]) -> SigResult<Self::Signature> {
+            Self::Signature::try_from(input)
+        }
+    }
+
+    impl<N: RsaLength> YubiRsa<N> {
+        /// https://www.rfc-editor.org/rfc/rfc8017#section-9.2
+        fn emsa_pkcs1_1_5(digest: OctetString) -> Result<Vec<u8>> {
+            /// https://www.rfc-editor.org/rfc/rfc8017#appendix-A.2.4
+            #[derive(Debug, Sequence)]
+            struct DigestInfo {
+                digest_algorithm: AlgorithmIdentifierOwned,
+                digest: OctetString,
+            }
+
+            let em_len = N::BIT_LENGTH / 8;
+
+            let null = Any::null();
+
+            let t = DigestInfo {
+                digest_algorithm: AlgorithmIdentifierOwned {
+                    oid: rfc5912::ID_SHA_256,
+                    parameters: Some(null),
+                },
+                digest,
            };
+            let t = t.to_der()?;

-        RsaPublicKey::new(n, e).map_err(|_| Error::InvalidObject)
-    }
+            let ps = vec![0xff; em_len - t.len() - 3];
+            assert!(ps.len() >= 8, "spec violation");

-    /// From [RFC 5480](https://tools.ietf.org/html/rfc5480#section-2.1.1):
-    /// ```text
-    /// ECParameters ::= CHOICE {
-    ///   namedCurve         OBJECT IDENTIFIER
-    ///   -- implicitCurve   NULL
-    ///   -- specifiedCurve  SpecifiedECDomain
-    /// }
-    /// ```
-    pub(super) fn ec_parameters(parameters: &Any<'_>) -> Result<AlgorithmId> {
-        let curve_oid = parameters.as_oid().map_err(|_| Error::InvalidObject)?;
-
-        match curve_oid.to_string().as_str() {
-            OID_NIST_P256 => Ok(AlgorithmId::EccP256),
-            OID_NIST_P384 => Ok(AlgorithmId::EccP384),
-            _ => Err(Error::AlgorithmError),
-        }
+            let mut out = Vec::with_capacity(em_len);
+            out.write(&[0x00, 0x01]).map_err(|_| Error::MemoryError)?;
+            out.write(&ps).map_err(|_| Error::MemoryError)?;
+            out.write(&[0x00]).map_err(|_| Error::MemoryError)?;
+            out.write(&t).map_err(|_| Error::MemoryError)?;
+            Ok(out)
        }
    }

-mod write_pki {
-    use cookie_factory::{SerializeFn, WriteContext};
-    use rsa::{BigUint, PublicKeyParts, RsaPublicKey};
-    use std::io::Write;
-    use x509::der::write::{der_integer, der_sequence};
-
-    /// Encodes a usize as an ASN.1 integer using DER.
-    fn der_integer_biguint<'a, W: Write + 'a>(num: &'a BigUint) -> impl SerializeFn<W> + 'a {
-        move |w: WriteContext<W>| der_integer(&num.to_bytes_be())(w)
+    /// The entrypoint to sign data with the yubikey.
+    pub struct Signer<'y, KT: KeyType> {
+        yubikey: RefCell<&'y mut YubiKey>,
+        key: SlotId,
+        public_key: KT::VerifyingKey,
    }

-    /// From [RFC 8017](https://tools.ietf.org/html/rfc8017#appendix-A.1.1):
-    /// ```text
-    /// RSAPublicKey ::= SEQUENCE {
-    ///     modulus           INTEGER,  -- n
-    ///     publicExponent    INTEGER   -- e
-    /// }
-    /// ```
-    pub(super) fn rsa_pubkey<'a, W: Write + 'a>(
-        pubkey: &'a RsaPublicKey,
-    ) -> impl SerializeFn<W> + 'a {
-        der_sequence((
-            der_integer_biguint(pubkey.n()),
-            der_integer_biguint(pubkey.e()),
-        ))
+    impl<'y, KT: KeyType> Signer<'y, KT> {
+        /// Create new Signer
+        pub fn new(
+            yubikey: &'y mut YubiKey,
+            key: SlotId,
+            subject_pki: SubjectPublicKeyInfoRef<'_>,
+        ) -> Result<Self> {
+            let public_key = KT::PublicKey::try_from(subject_pki).map_err(|_| Error::ParseError)?;
+            let public_key = public_key.into();
+
+            Ok(Self {
+                yubikey: RefCell::new(yubikey),
+                key,
+                public_key,
+            })
+        }
+    }
+
+    impl<KT: KeyType> Keypair for Signer<'_, KT> {
+        type VerifyingKey = KT::VerifyingKey;
+        fn verifying_key(&self) -> <Self as Keypair>::VerifyingKey {
+            self.public_key.clone()
+        }
+    }
+
+    impl<KT: KeyType> DynSignatureAlgorithmIdentifier for Signer<'_, KT> {
+        fn signature_algorithm_identifier(&self) -> spki::Result<AlgorithmIdentifierOwned> {
+            self.verifying_key().signature_algorithm_identifier()
+        }
+    }
+
+    impl<KT: KeyType> signature::Signer<KT::Signature> for Signer<'_, KT> {
+        fn try_sign(&self, msg: &[u8]) -> SigResult<KT::Signature> {
+            let data = KT::prepare(msg)?;
+
+            let out = sign_data(
+                &mut self.yubikey.borrow_mut(),
+                &data,
+                KT::ALGORITHM,
+                self.key,
+            )
+            .map_err(signature::Error::from_source)?;
+            let out = KT::read_signature(&out)?;
+            Ok(out)
+        }
    }
 }
@@ -30,7 +30,7 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

-use crate::{Error, Result, YubiKey};
+use crate::{Result, YubiKey};
 use std::fmt::{self, Debug, Display};
 use uuid::Uuid;

@@ -61,6 +61,7 @@ const OBJ_CHUID: u32 = 0x005f_c102;
 /// - 0x35: Exp. Date (hard-coded)
 /// - 0x3e: Signature (hard-coded, empty)
 /// - 0xfe: Error Detection Code (hard-coded)
+#[allow(dead_code)]
 const CHUID_TMPL: &[u8] = &[
    0x30, 0x19, 0xd4, 0xe7, 0x39, 0xda, 0x73, 0x9c, 0xed, 0x39, 0xce, 0x73, 0x9d, 0x83, 0x68, 0x58,
    0x21, 0x08, 0x42, 0x10, 0x84, 0x21, 0xc8, 0x42, 0x10, 0xc3, 0xeb, 0x34, 0x10, 0x00, 0x00, 0x00,
@@ -86,12 +87,13 @@ impl ChuId {
    pub fn fascn(&self) -> [u8; Self::FASCN_SIZE] {
        self.0[CHUID_FASCN_OFFS..(CHUID_FASCN_OFFS + Self::FASCN_SIZE)]
            .try_into()
-            .unwrap()
+            .expect("should be FASCN_SIZE")
    }

    /// Return Card UUID/GUID component of CHUID
    pub fn uuid(&self) -> Uuid {
-        Uuid::from_slice(&self.0[CHUID_GUID_OFFS..(CHUID_GUID_OFFS + 16)]).unwrap()
+        Uuid::from_slice(&self.0[CHUID_GUID_OFFS..(CHUID_GUID_OFFS + 16)])
+            .expect("should be UUID-sized")
    }

    /// Return expiration date component of CHUID
@@ -99,24 +101,18 @@ impl ChuId {
    pub fn expiration(&self) -> [u8; Self::EXPIRATION_SIZE] {
        self.0[CHUID_EXPIRATION_OFFS..(CHUID_EXPIRATION_OFFS + Self::EXPIRATION_SIZE)]
            .try_into()
-            .unwrap()
+            .expect("should be EXPIRATION_SIZE")
    }

    /// Get Cardholder Unique Identifier (CHUID)
    pub fn get(yubikey: &mut YubiKey) -> Result<ChuId> {
        let txn = yubikey.begin_transaction()?;
        let response = txn.fetch_object(OBJ_CHUID)?;
-
-        if response.len() != CHUID_TMPL.len() {
-            return Err(Error::GenericError);
-        }
-
-        Ok(ChuId(response[..Self::BYTE_SIZE].try_into().unwrap()))
+        Ok(response[..Self::BYTE_SIZE].try_into().map(Self)?)
    }

    /// Set Cardholder Unique Identifier (CHUID)
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn set(&self, yubikey: &mut YubiKey) -> Result<()> {
        let mut buf = CHUID_TMPL.to_vec();
        buf[..Self::BYTE_SIZE].copy_from_slice(&self.0);
@@ -111,7 +111,7 @@ impl Config {
                    error!("pin timestamp in admin metadata is an invalid size");
                } else {
                    // TODO(tarcieri): double-check endianness is correct
-                    let pin_last_changed = u32::from_le_bytes(item.try_into().unwrap());
+                    let pin_last_changed = u32::from_le_bytes([item[0], item[1], item[2], item[3]]);

                    if pin_last_changed != 0 {
                        config.pin_last_changed =
@@ -1,5 +1,7 @@
 //! Miscellaneous constant values

+#![allow(dead_code)]
+
 /// YubiKey max buffer size
 pub(crate) const CB_BUF_MAX: usize = 3072;

@@ -7,7 +9,6 @@ pub(crate) const CB_BUF_MAX: usize = 3072;
 pub(crate) const CB_OBJ_MAX: usize = CB_BUF_MAX - 9;

 pub(crate) const CB_OBJ_TAG_MIN: usize = 2; // 1 byte tag + 1 byte len
-#[cfg(feature = "untested")]
 pub(crate) const CB_OBJ_TAG_MAX: usize = CB_OBJ_TAG_MIN + 2; // 1 byte tag + 3 bytes len

 // Admin tags
@@ -18,3 +19,19 @@ pub(crate) const TAG_ADMIN_TIMESTAMP: u8 = 0x83;
 // Protected tags
 pub(crate) const TAG_PROTECTED_FLAGS_1: u8 = 0x81;
 pub(crate) const TAG_PROTECTED_MGM: u8 = 0x89;
+
+// Management
+pub(crate) const TAG_USB_SUPPORTED: u8 = 0x01;
+pub(crate) const TAG_SERIAL: u8 = 0x02;
+pub(crate) const TAG_USB_ENABLED: u8 = 0x03;
+pub(crate) const TAG_FORM_FACTOR: u8 = 0x04;
+pub(crate) const TAG_VERSION: u8 = 0x05;
+pub(crate) const TAG_AUTO_EJECT_TIMEOUT: u8 = 0x06;
+pub(crate) const TAG_CHALRESP_TIMEOUT: u8 = 0x07;
+pub(crate) const TAG_DEVICE_FLAGS: u8 = 0x08;
+pub(crate) const TAG_APP_VERSIONS: u8 = 0x09;
+pub(crate) const TAG_CONFIG_LOCK: u8 = 0x0A;
+pub(crate) const TAG_UNLOCK: u8 = 0x0B;
+pub(crate) const TAG_REBOOT: u8 = 0x0C;
+pub(crate) const TAG_NFC_SUPPORTED: u8 = 0x0D;
+pub(crate) const TAG_NFC_ENABLED: u8 = 0x0E;
@@ -57,6 +57,9 @@ pub enum Error {
    /// Authentication error
    AuthenticationError,

+    /// Error while building a certificate
+    CertificateBuilder,
+
    /// Generic error
    GenericError,

@@ -132,10 +135,11 @@ impl Error {
            Error::AlgorithmError => f.write_str("algorithm error"),
            Error::AppletError => f.write_str("applet error"),
            Error::AppletNotFound { applet_name } => {
-                f.write_str(&format!("{} applet not found", applet_name))
+                f.write_str(&format!("{applet_name} applet not found"))
            }
            Error::ArgumentError => f.write_str("argument error"),
            Error::AuthenticationError => f.write_str("authentication error"),
+            Error::CertificateBuilder => f.write_str("certificate builder error"),
            Error::GenericError => f.write_str("generic error"),
            Error::InvalidObject => f.write_str("invalid object"),
            Error::KeyError => f.write_str("key error"),
@@ -146,7 +150,7 @@ impl Error {

            Error::PcscError {
                inner: Some(pcsc_error),
-            } => f.write_fmt(format_args!("PC/SC error: {}", pcsc_error)),
+            } => f.write_fmt(format_args!("PC/SC error: {pcsc_error}")),

            Error::PcscError { .. } => f.write_str("PC/SC error"),

@@ -164,6 +168,18 @@ impl Display for Error {
    }
 }

+impl From<std::array::TryFromSliceError> for Error {
+    fn from(_: std::array::TryFromSliceError) -> Error {
+        Error::SizeError
+    }
+}
+
+impl From<std::time::SystemTimeError> for Error {
+    fn from(_: std::time::SystemTimeError) -> Error {
+        Error::GenericError
+    }
+}
+
 impl From<pcsc::Error> for Error {
    fn from(err: pcsc::Error) -> Error {
        Error::PcscError { inner: Some(err) }
@@ -179,3 +195,15 @@ impl std::error::Error for Error {
        }
    }
 }
+
+impl From<der::Error> for Error {
+    fn from(_err: der::Error) -> Error {
+        Error::ParseError
+    }
+}
+
+impl From<x509_cert::builder::Error> for Error {
+    fn from(_err: x509_cert::builder::Error) -> Error {
+        Error::CertificateBuilder
+    }
+}
@@ -2,9 +2,16 @@
 #![doc(
    html_logo_url = "https://raw.githubusercontent.com/iqlusioninc/yubikey.rs/main/img/logo-sq.png"
 )]
-#![cfg_attr(docsrs, feature(doc_cfg))]
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
 #![forbid(unsafe_code)]
-#![warn(missing_docs, rust_2018_idioms, trivial_casts, unused_qualifications)]
+#![warn(
+    clippy::mod_module_files,
+    clippy::unwrap_used,
+    missing_docs,
+    rust_2018_idioms,
+    unused_lifetimes,
+    unused_qualifications
+)]

 // Adapted from yubico-piv-tool:
 // <https://github.com/Yubico/yubico-piv-tool/>
@@ -44,7 +51,7 @@ mod config;
 mod consts;
 mod error;
 mod metadata;
-mod mgm;
+pub mod mgm;
 #[cfg(feature = "untested")]
 mod mscmap;
 #[cfg(feature = "untested")]
@@ -64,7 +71,7 @@ pub use crate::{
    chuid::ChuId,
    config::Config,
    error::{Error, Result},
-    mgm::{MgmKey, MgmType},
+    mgm::{MgmAlgorithmId, MgmKey, MgmType},
    piv::Key,
    policy::{PinPolicy, TouchPolicy},
    reader::Context,
@@ -30,16 +30,15 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

-use std::marker::PhantomData;
+use std::{iter, marker::PhantomData};
 use zeroize::Zeroizing;

-use crate::{serialization::*, transaction::Transaction, Buffer, Error, Result};
-
-#[cfg(feature = "untested")]
-use crate::consts::{CB_OBJ_MAX, CB_OBJ_TAG_MAX};
-
-#[cfg(feature = "untested")]
-use std::iter;
+use crate::{
+    consts::{CB_OBJ_MAX, CB_OBJ_TAG_MAX},
+    serialization::*,
+    transaction::Transaction,
+    Buffer, Error, Result,
+};

 const TAG_ADMIN: u8 = 0x80;
 const TAG_PROTECTED: u8 = 0x88;
@@ -71,7 +70,7 @@ impl<T: MetadataType> Default for Metadata<T> {
    fn default() -> Self {
        Metadata {
            inner: Zeroizing::new(vec![]),
-            _marker: PhantomData::default(),
+            _marker: PhantomData,
        }
    }
 }
@@ -82,13 +81,11 @@ impl<T: MetadataType> Metadata<T> {
        let data = txn.fetch_object(T::obj_id())?;
        Ok(Metadata {
            inner: Tlv::parse_single(data, T::tag())?,
-            _marker: PhantomData::default(),
+            _marker: PhantomData,
        })
    }

    /// Write metadata
-    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub(crate) fn write(&self, txn: &Transaction<'_>) -> Result<()> {
        if self.inner.len() > CB_OBJ_MAX - CB_OBJ_TAG_MAX {
            return Err(Error::GenericError);
@@ -105,8 +102,6 @@ impl<T: MetadataType> Metadata<T> {
    }

    /// Delete metadata
-    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub(crate) fn delete(txn: &Transaction<'_>) -> Result<()> {
        txn.save_object(T::obj_id(), &[])
    }
@@ -129,8 +124,6 @@ impl<T: MetadataType> Metadata<T> {
    }

    /// Set metadata item
-    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub(crate) fn set_item(&mut self, tag: u8, item: &[u8]) -> Result<()> {
        let mut cb_temp: usize = 0;
        let mut tag_temp: u8 = 0;
@@ -160,8 +153,10 @@ impl<T: MetadataType> Metadata<T> {

            // We did not find an existing tag, append
            assert_eq!(offset, self.inner.len());
-            self.inner
-                .extend(iter::repeat(0).take(1 + get_length_size(item.len()) + item.len()));
+            self.inner.extend(iter::repeat_n(
+                0,
+                1 + get_length_size(item.len()) + item.len(),
+            ));
            Tlv::write(&mut self.inner[offset..], tag, item)?;

            return Ok(());
@@ -196,7 +191,7 @@ impl<T: MetadataType> Metadata<T> {
        // Move remaining data
        let orig_len = self.inner.len();
        if cb_moved > 0 {
-            self.inner.extend(iter::repeat(0).take(cb_moved as usize));
+            self.inner.extend(iter::repeat_n(0, cb_moved as usize));
        }
        self.inner.copy_within(
            next_offset..orig_len,
@@ -217,7 +212,6 @@ impl<T: MetadataType> Metadata<T> {
 }

 /// Get the size of a length tag for the given length
-#[cfg(feature = "untested")]
 fn get_length_size(length: usize) -> usize {
    if length < 0x80 {
        1
@@ -41,7 +41,6 @@ const TAG_MSCMAP: u8 = 0x81;
 ///
 /// Defined in Microsoft's Smart Card Minidriver Specification:
 /// <https://docs.microsoft.com/en-us/previous-versions/windows/hardware/design/dn631754(v=vs.85)>
-#[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
 #[derive(Clone, Debug)]
 pub struct MsContainer {
    /// Container name.
@@ -141,7 +140,7 @@ impl MsContainer {
        let name_bytes_len = Self::NAME_LEN * 2;

        for (i, chunk) in bytes[..name_bytes_len].chunks_exact(2).enumerate() {
-            name[i] = u16::from_le_bytes(chunk.try_into().unwrap());
+            name[i] = u16::from_le_bytes([chunk[0], chunk[1]]);
        }

        let mut cert_fingerprint = [0u8; 20];
@@ -151,11 +150,10 @@ impl MsContainer {
            name,
            slot: bytes[name_bytes_len].try_into()?,
            key_spec: bytes[name_bytes_len + 1],
-            key_size_bits: u16::from_le_bytes(
-                bytes[(name_bytes_len + 2)..(name_bytes_len + 4)]
-                    .try_into()
-                    .unwrap(),
-            ),
+            key_size_bits: u16::from_le_bytes([
+                bytes[name_bytes_len + 2],
+                bytes[name_bytes_len + 3],
+            ]),
            flags: bytes[name_bytes_len + 4],
            pin_id: bytes[name_bytes_len + 5],
            associated_echd_container: bytes[name_bytes_len + 6],
@@ -184,7 +182,10 @@ impl MsContainer {
        bytes.push(self.pin_id);
        bytes.push(self.associated_echd_container);
        bytes.extend_from_slice(&self.cert_fingerprint);
-        bytes.as_slice().try_into().unwrap()
+        bytes
+            .as_slice()
+            .try_into()
+            .expect("should be REC_LEN-sized")
    }
 }

@@ -57,7 +57,6 @@ const TAG_MSROOTS_MID: u8 = 0x83;
 ///
 /// For more information, see:
 /// <https://docs.microsoft.com/en-us/windows-hardware/drivers/smartcard/developer-guidelines#-interoperability-with-msroots>
-#[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
 pub struct MsRoots(Vec<u8>);

 impl MsRoots {
@@ -97,10 +96,9 @@ impl MsRoots {
            }
        }

-        MsRoots::new(&data).map(Some).map_err(|e| {
-            error!("error parsing msroots: {:?}", e);
-            e
-        })
+        MsRoots::new(&data)
+            .map(Some)
+            .inspect_err(|e| error!("error parsing msroots: {:?}", e))
    }

    /// Write `msroots` file to YubiKey
@@ -6,10 +6,10 @@
 //! Supported algorithms:
 //!
 //! - **Encryption**:
-//!   - RSA: `RSA1024`, `RSA2048`
+//!   - RSA: `RSA1024`, `RSA2048`, `RSA3072`, `RSA4096`
 //!   - ECC: `ECCP256`, `ECCP384` (NIST curves: P-256, P-384)
 //! - **Signatures**:
-//!   - RSASSA-PKCS#1v1.5: `RSA1024`, `RSA2048`
+//!   - RSASSA-PKCS#1v1.5: `RSA1024`, `RSA2048`, `RSA3072`, `RSA4096`
 //!   - ECDSA: `ECCP256`, `ECCP384` (NIST curves: P-256, P-384)

 // Adapted from yubico-piv-tool:
@@ -44,35 +44,38 @@

 use crate::{
    apdu::{Ins, StatusWords},
-    certificate::{self, Certificate, PublicKeyInfo},
-    consts::CB_OBJ_MAX,
+    certificate::{self, Certificate},
    error::{Error, Result},
+    mgm::MgmAlgorithmId,
    policy::{PinPolicy, TouchPolicy},
    serialization::*,
    setting,
    yubikey::YubiKey,
    Buffer, ObjectId,
 };
-use elliptic_curve::sec1::EncodedPoint as EcPublicKey;
+use elliptic_curve::{sec1::Sec1Point as EcPublicKey, PublicKey};
 use log::{debug, error, warn};
 use p256::NistP256;
 use p384::NistP384;
-use rsa::{BigUint, RsaPublicKey};
+use rsa::{pkcs8::EncodePublicKey, BoxedUint, RsaPublicKey};
 use std::{
    fmt::{Display, Formatter},
    str::FromStr,
 };
-
-#[cfg(feature = "untested")]
-use {
-    num_bigint_dig::traits::ModInverse,
-    num_integer::Integer,
-    num_traits::{FromPrimitive, One},
+use x509_cert::{
+    der::{asn1::BitString, Decode},
+    spki::{AlgorithmIdentifier, ObjectIdentifier, SubjectPublicKeyInfoOwned},
 };

 #[cfg(feature = "untested")]
 use zeroize::Zeroizing;

+#[cfg(feature = "untested")]
+use crate::consts::CB_OBJ_MAX;
+
+#[cfg(feature = "untested")]
+use rsa::{traits::PrivateKeyParts, RsaPrivateKey};
+
 /// PIV Applet Name
 pub(crate) const APPLET_NAME: &str = "PIV";

@@ -86,6 +89,9 @@ const TAG_RSA_MODULUS: u8 = 0x81;
 const TAG_RSA_EXP: u8 = 0x82;
 const TAG_ECC_POINT: u8 = 0x86;

+/// OID for ed25519 and x25519 algorithms
+pub const OID_X25519: ObjectIdentifier = ObjectIdentifier::new_unwrap("1.3.101.110");
+
 #[cfg(feature = "untested")]
 const KEYDATA_LEN: usize = 1024;

@@ -171,9 +177,9 @@ impl From<SlotId> for u8 {
 impl Display for SlotId {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        match self {
-            SlotId::Management(r) => write!(f, "{:?}", r),
-            SlotId::Retired(r) => write!(f, "{:?}", r),
-            _ => write!(f, "{:?}", self),
+            SlotId::Management(r) => write!(f, "{r:?}"),
+            SlotId::Retired(r) => write!(f, "{r:?}"),
+            _ => write!(f, "{self:?}"),
        }
    }
 }
@@ -326,7 +332,7 @@ impl From<RetiredSlotId> for u8 {

 impl Display for RetiredSlotId {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{:?}", self)
+        write!(f, "{self:?}")
    }
 }

@@ -409,7 +415,7 @@ impl From<ManagementSlotId> for u8 {

 impl Display for ManagementSlotId {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{:?}", self)
+        write!(f, "{self:?}")
    }
 }

@@ -441,10 +447,11 @@ impl ManagementSlotId {
 }

 /// Personal Identity Verification (PIV) key slots
-pub const SLOTS: [SlotId; 27] = [
+pub const SLOTS: [SlotId; 28] = [
    SlotId::Authentication,
    SlotId::Signature,
    SlotId::KeyManagement,
+    SlotId::Attestation,
    SlotId::Retired(RetiredSlotId::R1),
    SlotId::Retired(RetiredSlotId::R2),
    SlotId::Retired(RetiredSlotId::R3),
@@ -480,11 +487,23 @@ pub enum AlgorithmId {
    /// 2048-bit RSA.
    Rsa2048,

+    /// 3072-bit RSA. Requires firmware 5.7 or newer
+    Rsa3072,
+
+    /// 4096-bit RSA. Requires firmware 5.7 or newer
+    Rsa4096,
+
    /// ECDSA with the NIST P256 curve.
    EccP256,

    /// ECDSA with the NIST P384 curve.
    EccP384,
+
+    /// ED25519
+    Ed25519,
+
+    /// X25519
+    X25519,
 }

 impl TryFrom<u8> for AlgorithmId {
@@ -494,8 +513,12 @@ impl TryFrom<u8> for AlgorithmId {
        match value {
            0x06 => Ok(AlgorithmId::Rsa1024),
            0x07 => Ok(AlgorithmId::Rsa2048),
+            0x05 => Ok(AlgorithmId::Rsa3072),
+            0x16 => Ok(AlgorithmId::Rsa4096),
            0x11 => Ok(AlgorithmId::EccP256),
            0x14 => Ok(AlgorithmId::EccP384),
+            0xE0 => Ok(AlgorithmId::Ed25519),
+            0xE1 => Ok(AlgorithmId::X25519),
            _ => Err(Error::AlgorithmError),
        }
    }
@@ -506,8 +529,12 @@ impl From<AlgorithmId> for u8 {
        match id {
            AlgorithmId::Rsa1024 => 0x06,
            AlgorithmId::Rsa2048 => 0x07,
+            AlgorithmId::Rsa3072 => 0x05,
+            AlgorithmId::Rsa4096 => 0x16,
            AlgorithmId::EccP256 => 0x11,
            AlgorithmId::EccP384 => 0x14,
+            AlgorithmId::Ed25519 => 0xE0,
+            AlgorithmId::X25519 => 0xE1,
        }
    }
 }
@@ -519,22 +546,29 @@ impl AlgorithmId {
    }

    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    fn get_elem_len(self) -> usize {
        match self {
            AlgorithmId::Rsa1024 => 64,
            AlgorithmId::Rsa2048 => 128,
+            AlgorithmId::Rsa3072 => 192,
+            AlgorithmId::Rsa4096 => 256,
            AlgorithmId::EccP256 => 32,
            AlgorithmId::EccP384 => 48,
+            AlgorithmId::Ed25519 => 32,
+            AlgorithmId::X25519 => 32,
        }
    }

    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    fn get_param_tag(self) -> u8 {
        match self {
-            AlgorithmId::Rsa1024 | AlgorithmId::Rsa2048 => 0x01,
+            AlgorithmId::Rsa1024
+            | AlgorithmId::Rsa2048
+            | AlgorithmId::Rsa3072
+            | AlgorithmId::Rsa4096 => 0x01,
            AlgorithmId::EccP256 | AlgorithmId::EccP384 => 0x6,
+            AlgorithmId::Ed25519 => 0x07,
+            AlgorithmId::X25519 => 0x08,
        }
    }
 }
@@ -591,7 +625,7 @@ pub fn generate(
    algorithm: AlgorithmId,
    pin_policy: PinPolicy,
    touch_policy: TouchPolicy,
-) -> Result<PublicKeyInfo> {
+) -> Result<SubjectPublicKeyInfoOwned> {
    // Keygen messages
    // TODO(tarcieri): extract these into an I18N-handling type?
    const SZ_SETTING_ROCA: &str = "Enable_Unsafe_Keygen_ROCA";
@@ -606,7 +640,10 @@ pub fn generate(
    let setting_roca: setting::Setting;

    match algorithm {
-        AlgorithmId::Rsa1024 | AlgorithmId::Rsa2048 => {
+        AlgorithmId::Rsa1024
+        | AlgorithmId::Rsa2048
+        | AlgorithmId::Rsa3072
+        | AlgorithmId::Rsa4096 => {
            if yubikey.version.major == 4
                && (yubikey.version.minor < 3
                    || yubikey.version.minor == 3 && (yubikey.version.patch < 5))
@@ -701,7 +738,6 @@ pub fn generate(
 }

 #[cfg(feature = "untested")]
-#[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
 fn write_key(
    yubikey: &mut YubiKey,
    slot: SlotId,
@@ -750,7 +786,6 @@ fn write_key(

 /// The key data that makes up an RSA key.
 #[cfg(feature = "untested")]
-#[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
 pub struct RsaKeyData {
    /// The secret prime `p`.
    p: Buffer,
@@ -766,41 +801,51 @@ pub struct RsaKeyData {

 #[cfg(feature = "untested")]
 impl RsaKeyData {
-    /// Generates a new RSA key data set from two randomly generated, secret, primes.
+    /// Generates a new RSA key data set from two (randomly generated) secret primes.
    ///
-    /// Panics if `secret_p` or `secret_q` are invalid primes.
-    pub fn new(secret_p: &[u8], secret_q: &[u8]) -> Self {
-        let p = BigUint::from_bytes_be(secret_p);
-        let q = BigUint::from_bytes_be(secret_q);
+    /// # Returns
+    /// - `Ok(key_data)` if `secret_p` and `secret_q` are valid primes.
+    /// - `Err(Error::AlgorithmError)` if `secret_p`/`secret_q` are invalid primes.
+    pub fn new(secret_p: &[u8], secret_q: &[u8]) -> Result<Self> {
+        let p = BoxedUint::from_be_slice_vartime(secret_p);
+        let q = BoxedUint::from_be_slice_vartime(secret_q);
+        let exp = BoxedUint::from(KEYDATA_RSA_EXP);

-        let totient = {
-            let p_t = &p - BigUint::one();
-            let q_t = &p - BigUint::one();
+        let mut private_key = RsaPrivateKey::from_p_q(p.clone(), q.clone(), exp)
+            .map_err(|_| Error::AlgorithmError)?;
+        private_key
+            .precompute()
+            .map_err(|_| Error::AlgorithmError)?;

-            p_t.lcm(&q_t)
-        };
-
-        let exp = BigUint::from_u64(KEYDATA_RSA_EXP).unwrap();
-
-        let d = exp.mod_inverse(&totient).unwrap();
-        let d = d.to_biguint().unwrap();
-
-        // We calculate the optimization values ahead of time, instead of making the user
-        // do so.
-
-        let dp = &d % (&p - BigUint::one());
-        let dq = &d % (&q - BigUint::one());
-
-        let qinv = q.clone().mod_inverse(&p).unwrap();
-        let (_, qinv) = qinv.to_bytes_be();
-
-        RsaKeyData {
-            p: Zeroizing::new(p.to_bytes_be()),
-            q: Zeroizing::new(q.to_bytes_be()),
-            dp: Zeroizing::new(dp.to_bytes_be()),
-            dq: Zeroizing::new(dq.to_bytes_be()),
-            qinv: Zeroizing::new(qinv),
-        }
+        Ok(RsaKeyData {
+            p: Zeroizing::new(p.to_be_bytes().to_vec()),
+            q: Zeroizing::new(q.to_be_bytes().to_vec()),
+            dp: Zeroizing::new(
+                private_key
+                    .dp()
+                    .expect("invariant violation: precompute should fill the field")
+                    .clone()
+                    .to_be_bytes()
+                    .to_vec(),
+            ),
+            dq: Zeroizing::new(
+                private_key
+                    .dq()
+                    .expect("invariant violation: precompute should fill the field")
+                    .clone()
+                    .to_be_bytes()
+                    .to_vec(),
+            ),
+            qinv: Zeroizing::new(
+                private_key
+                    .qinv()
+                    .expect("invariant violation: precompute should fill the field")
+                    .clone()
+                    .retrieve()
+                    .to_be_bytes()
+                    .to_vec(),
+            ),
+        })
    }

    fn total_len(&self) -> usize {
@@ -810,9 +855,8 @@ impl RsaKeyData {

 /// Imports a private RSA encryption or signing key into the YubiKey.
 ///
-/// Errors if `algorithm` isn't `AlgorithmId::Rsa1024` or `AlgorithmId::Rsa2048`.
+/// Errors if `algorithm` isn't `AlgorithmId::Rsa1024` or `AlgorithmId::Rsa2048` or `AlgorithmId::Rsa3072` or `AlgorithmId::Rsa4096`.
 #[cfg(feature = "untested")]
-#[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
 pub fn import_rsa_key(
    yubikey: &mut YubiKey,
    slot: SlotId,
@@ -822,7 +866,10 @@ pub fn import_rsa_key(
    pin_policy: PinPolicy,
 ) -> Result<()> {
    match algorithm {
-        AlgorithmId::Rsa1024 | AlgorithmId::Rsa2048 => (),
+        AlgorithmId::Rsa1024
+        | AlgorithmId::Rsa2048
+        | AlgorithmId::Rsa3072
+        | AlgorithmId::Rsa4096 => (),
        _ => return Err(Error::AlgorithmError),
    }

@@ -847,7 +894,6 @@ pub fn import_rsa_key(
 ///
 /// Errors if `algorithm` isn't `AlgorithmId::EccP256` or ` AlgorithmId::EccP384`.
 #[cfg(feature = "untested")]
-#[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
 pub fn import_ecc_key(
    yubikey: &mut YubiKey,
    slot: SlotId,
@@ -872,11 +918,38 @@ pub fn import_ecc_key(
    Ok(())
 }

+/// Imports a private ECDH/EdDSA encryption or signing key into the YubiKey.
+///
+/// Errors if `algorithm` isn't `AlgorithmId::Ed25519` or ` AlgorithmId::X25519`.
+#[cfg(feature = "untested")]
+pub fn import_cv_key(
+    yubikey: &mut YubiKey,
+    slot: SlotId,
+    algorithm: AlgorithmId,
+    key_data: &[u8],
+    touch_policy: TouchPolicy,
+    pin_policy: PinPolicy,
+) -> Result<()> {
+    match algorithm {
+        AlgorithmId::Ed25519 | AlgorithmId::X25519 => (),
+        _ => return Err(Error::AlgorithmError),
+    }
+
+    if key_data.len() > KEYDATA_LEN {
+        return Err(Error::SizeError);
+    }
+
+    let params = vec![key_data];
+
+    write_key(yubikey, slot, params, pin_policy, touch_policy, algorithm)?;
+
+    Ok(())
+}
+
 /// Generate an attestation certificate for a stored key.
 ///
 /// <https://developers.yubico.com/PIV/Introduction/PIV_attestation.html>
 #[cfg(feature = "untested")]
-#[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
 pub fn attest(yubikey: &mut YubiKey, key: SlotId) -> Result<Buffer> {
    let templ = [0, Ins::Attest.code(), key.into(), 0];
    let txn = yubikey.begin_transaction()?;
@@ -912,7 +985,6 @@ pub fn sign_data(

 /// Decrypt data using a PIV key.
 #[cfg(feature = "untested")]
-#[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
 pub fn decrypt_data(
    yubikey: &mut YubiKey,
    input: &[u8],
@@ -928,34 +1000,21 @@ pub fn decrypt_data(
 /// Read metadata
 pub fn metadata(yubikey: &mut YubiKey, slot: SlotId) -> Result<SlotMetadata> {
    let txn = yubikey.begin_transaction()?;
-    let templ = [0, Ins::GetMetadata.code(), 0, slot.into()];

-    let response = txn.transfer_data(&templ, &[], CB_OBJ_MAX)?;
-
-    if !response.is_success() {
-        if response.status_words() == StatusWords::NotSupportedError {
-            return Err(Error::NotSupported); // Requires firmware 5.2.3
-        } else {
-            return Err(Error::GenericError);
-        }
-    }
-
-    let buf = Buffer::new(response.data().into());
-
-    SlotMetadata::try_from(buf)
+    txn.get_metadata(slot)
 }

 /// Metadata from a slot
 #[derive(Debug)]
 pub struct SlotMetadata {
    /// Algorithm / Type of key
-    pub algorithm: ManagementAlgorithmId,
+    pub algorithm: SlotAlgorithmId,
    /// PIN and touch policy
    pub policy: Option<(PinPolicy, TouchPolicy)>,
    /// Imported or generated key
    pub origin: Option<Origin>,
    /// Pub key of the key
-    pub public: Option<PublicKeyInfo>,
+    pub public: Option<SubjectPublicKeyInfoOwned>,
    /// Whether PIN PUK and management key are default
    pub default: Option<bool>,
    /// Number of retries left
@@ -970,13 +1029,14 @@ impl TryFrom<Buffer> for SlotMetadata {
            combinator::{eof, map_res},
            multi::fold_many1,
            number::complete::u8,
+            Parser,
        };

        let out = fold_many1(
            |input| Tlv::parse(input).map_err(|_| nom::Err::Error(())),
            || {
                Ok(SlotMetadata {
-                    algorithm: ManagementAlgorithmId::PinPuk,
+                    algorithm: SlotAlgorithmId::PinPuk,
                    policy: None,
                    origin: None,
                    public: None,
@@ -987,15 +1047,15 @@ impl TryFrom<Buffer> for SlotMetadata {
            |acc: Result<SlotMetadata>, tlv| match acc {
                Ok(mut metadata) => match tlv.tag {
                    1 => {
-                        metadata.algorithm = ManagementAlgorithmId::try_from(tlv.value[0])?;
+                        metadata.algorithm = SlotAlgorithmId::try_from(tlv.value[0])?;
                        Ok(metadata)
                    }
                    2 => {
                        fn policy_parser(
                            i: &[u8],
                        ) -> nom::IResult<&[u8], (PinPolicy, TouchPolicy)> {
-                            let (i, pin) = map_res(u8, PinPolicy::try_from)(i)?;
-                            let (i, touch) = map_res(u8, TouchPolicy::try_from)(i)?;
+                            let (i, pin) = map_res(u8, PinPolicy::try_from).parse(i)?;
+                            let (i, touch) = map_res(u8, TouchPolicy::try_from).parse(i)?;
                            let (i, _) = eof(i)?;

                            Ok((i, (pin, touch)))
@@ -1007,7 +1067,7 @@ impl TryFrom<Buffer> for SlotMetadata {
                    }
                    3 => {
                        fn origin_parser(i: &[u8]) -> nom::IResult<&[u8], Origin> {
-                            let (i, origin) = map_res(u8, Origin::try_from)(i)?;
+                            let (i, origin) = map_res(u8, Origin::try_from).parse(i)?;
                            let (i, _) = eof(i)?;

                            Ok((i, origin))
@@ -1019,7 +1079,7 @@ impl TryFrom<Buffer> for SlotMetadata {
                    }
                    4 => {
                        match metadata.algorithm {
-                            ManagementAlgorithmId::Asymmetric(alg) => {
+                            SlotAlgorithmId::Asymmetric(alg) => {
                                metadata.public = Some(read_public_key(alg, tlv.value, false)?);
                            }
                            _ => Err(Error::ParseError)?,
@@ -1067,7 +1127,8 @@ impl TryFrom<Buffer> for SlotMetadata {
                },
                err => err,
            },
-        )(buf.as_ref());
+        )
+        .parse(buf.as_ref());

        match out {
            Ok((_, res)) => res,
@@ -1110,12 +1171,45 @@ fn read_public_key(
    algorithm: AlgorithmId,
    input: &[u8],
    skip_asn1_tag: bool,
-) -> Result<PublicKeyInfo> {
+) -> Result<SubjectPublicKeyInfoOwned> {
    // TODO(str4d): Response is wrapped in an ASN.1 TLV:
    //
    //    0x7f 0x49 -> Application | Constructed | 0x49
    match algorithm {
-        AlgorithmId::Rsa1024 | AlgorithmId::Rsa2048 => {
+        AlgorithmId::X25519 | AlgorithmId::Ed25519 => {
+            // 2-byte ASN.1 tag, 1-byte length (because all supported EC pubkey lengths
+            // are shorter than 128 bytes, fitting into a definite short ASN.1 length).
+            let data = if skip_asn1_tag { &input[3..] } else { input };
+
+            let (_, tlv) = Tlv::parse(data)?;
+            let pk_data: [u8; 32] = tlv.value.try_into().map_err(|_| Error::InvalidObject)?;
+
+            match algorithm {
+                AlgorithmId::Ed25519 => SubjectPublicKeyInfoOwned::from_der(
+                    ed25519_dalek::VerifyingKey::from_bytes(&pk_data)
+                        .map_err(|_| Error::InvalidObject)?
+                        .to_public_key_der()
+                        .map_err(|_| Error::InvalidObject)?
+                        .as_bytes(),
+                )
+                .map_err(|_| Error::InvalidObject),
+                AlgorithmId::X25519 => Ok(SubjectPublicKeyInfoOwned {
+                    algorithm: AlgorithmIdentifier {
+                        oid: OID_X25519,
+                        parameters: None,
+                    },
+                    subject_public_key: BitString::from_bytes(
+                        x25519_dalek::PublicKey::from(pk_data).as_bytes(),
+                    )
+                    .map_err(|_| Error::InvalidObject)?,
+                }),
+                _ => Err(Error::AlgorithmError),
+            }
+        }
+        AlgorithmId::Rsa1024
+        | AlgorithmId::Rsa2048
+        | AlgorithmId::Rsa3072
+        | AlgorithmId::Rsa4096 => {
            // It appears that the inner application-specific value returned by the
            // YubiKey is constructed such that RSA pubkeys can be parsed in two ways:
            //
@@ -1159,14 +1253,17 @@ fn read_public_key(
            }
            let exp = exp_tlv.value.to_vec();

-            Ok(PublicKeyInfo::Rsa {
-                algorithm,
-                pubkey: RsaPublicKey::new(
-                    BigUint::from_bytes_be(&modulus),
-                    BigUint::from_bytes_be(&exp),
+            let pubkey = RsaPublicKey::new(
+                BoxedUint::from_be_slice_vartime(&modulus),
+                BoxedUint::from_be_slice_vartime(&exp),
            )
-                .map_err(|_| Error::InvalidObject)?,
-            })
+            .map_err(|_| Error::InvalidObject)?;
+            Ok(SubjectPublicKeyInfoOwned::from_der(
+                pubkey
+                    .to_public_key_der()
+                    .map_err(|_| Error::ParseError)?
+                    .as_bytes(),
+            )?)
        }
        AlgorithmId::EccP256 | AlgorithmId::EccP384 => {
            // 2-byte ASN.1 tag, 1-byte length (because all supported EC pubkey lengths
@@ -1194,49 +1291,56 @@ fn read_public_key(

            let point = tlv.value.to_vec();

-            match algorithm {
-                AlgorithmId::EccP256 => {
-                    EcPublicKey::<NistP256>::from_bytes(point).map(PublicKeyInfo::EcP256)
-                }
-                AlgorithmId::EccP384 => {
-                    EcPublicKey::<NistP384>::from_bytes(point).map(PublicKeyInfo::EcP384)
-                }
+            let pubkey = match algorithm {
+                AlgorithmId::EccP256 => PublicKey::<NistP256>::try_from(
+                    EcPublicKey::<NistP256>::from_bytes(point).map_err(|_| Error::InvalidObject)?,
+                )
+                .map_err(|_| Error::InvalidObject)?
+                .to_public_key_der(),
+                AlgorithmId::EccP384 => PublicKey::<NistP384>::try_from(
+                    EcPublicKey::<NistP384>::from_bytes(point).map_err(|_| Error::InvalidObject)?,
+                )
+                .map_err(|_| Error::InvalidObject)?
+                .to_public_key_der(),
                _ => return Err(Error::AlgorithmError),
            }
-            .map_err(|_| Error::InvalidObject)
+            .map_err(|_| Error::InvalidObject)?;
+
+            Ok(SubjectPublicKeyInfoOwned::from_der(pubkey.as_bytes())?)
        }
    }
 }

 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 /// Algorithms as reported by the metadata command.
-pub enum ManagementAlgorithmId {
+pub enum SlotAlgorithmId {
    /// Used on PIN and PUK slots.
    PinPuk,
    /// Used on the key management slot.
-    ThreeDes,
+    Management(MgmAlgorithmId),
    /// Used on all other slots.
    Asymmetric(AlgorithmId),
 }

-impl TryFrom<u8> for ManagementAlgorithmId {
+impl TryFrom<u8> for SlotAlgorithmId {
    type Error = Error;

    fn try_from(value: u8) -> Result<Self> {
        match value {
-            0xff => Ok(ManagementAlgorithmId::PinPuk),
-            0x03 => Ok(ManagementAlgorithmId::ThreeDes),
-            oth => AlgorithmId::try_from(oth).map(ManagementAlgorithmId::Asymmetric),
+            0xff => Ok(SlotAlgorithmId::PinPuk),
+            oth => MgmAlgorithmId::try_from(oth)
+                .map(SlotAlgorithmId::Management)
+                .or_else(|_| AlgorithmId::try_from(oth).map(SlotAlgorithmId::Asymmetric)),
        }
    }
 }

-impl From<ManagementAlgorithmId> for u8 {
-    fn from(id: ManagementAlgorithmId) -> u8 {
+impl From<SlotAlgorithmId> for u8 {
+    fn from(id: SlotAlgorithmId) -> u8 {
        match id {
-            ManagementAlgorithmId::PinPuk => 0xff,
-            ManagementAlgorithmId::ThreeDes => 0x03,
-            ManagementAlgorithmId::Asymmetric(oth) => oth.into(),
+            SlotAlgorithmId::PinPuk => 0xff,
+            SlotAlgorithmId::Management(oth) => oth.into(),
+            SlotAlgorithmId::Asymmetric(oth) => oth.into(),
        }
    }
 }
@@ -1,6 +1,6 @@
 //! Support for enumerating available PC/SC card readers.

-use crate::{Result, YubiKey};
+use crate::{Error, Result, YubiKey};
 use std::{
    borrow::Cow,
    ffi::CStr,
@@ -43,7 +43,8 @@ impl Context {
        let Self { ctx, reader_names } = self;

        let reader_cstrs: Vec<_> = {
-            let c = ctx.lock().unwrap();
+            // TODO(tarcieri): better error?
+            let c = ctx.lock().map_err(|_| Error::GenericError)?;

            // ensure PC/SC context is valid
            c.is_valid()?;
@@ -90,7 +91,8 @@ impl<'ctx> Reader<'ctx> {

    /// Connect to this reader, returning its `pcsc::Card`.
    pub(crate) fn connect(&self) -> Result<pcsc::Card> {
-        let ctx = self.ctx.lock().unwrap();
+        // TODO(tarcieri): better error?
+        let ctx = self.ctx.lock().map_err(|_| Error::GenericError)?;
        Ok(ctx.connect(self.name, pcsc::ShareMode::Shared, pcsc::Protocols::T1)?)
    }
 }
@@ -41,7 +41,7 @@ use std::{
 };

 /// Source of how a setting was configured.
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
 pub enum SettingSource {
    /// User-specified setting: sourced via `YUBIKEY_PIV_*` environment vars.
    User,
@@ -51,15 +51,10 @@ pub enum SettingSource {
    Admin,

    /// Default setting.
+    #[default]
    Default,
 }

-impl Default for SettingSource {
-    fn default() -> Self {
-        Self::Default
-    }
-}
-
 /// Setting booleans: configuration values sourced from a file or the environment.
 ///
 /// These can be configured globally in `/etc/yubico/yubikeypiv.conf` by a
@@ -122,7 +117,7 @@ impl Setting {

    /// Get a setting boolean from an environment variable
    fn from_env(key: &str) -> Option<Self> {
-        env::var(format!("YUBIKEY_PIV_{}", key))
+        env::var(format!("YUBIKEY_PIV_{key}"))
            .ok()
            .map(|value| Setting {
                source: SettingSource::User,
@@ -5,6 +5,7 @@ use crate::{
    apdu::{Apdu, Ins, StatusWords},
    consts::{CB_BUF_MAX, CB_OBJ_MAX},
    error::{Error, Result},
+    mgm::MgmKey,
    otp,
    piv::{self, AlgorithmId, SlotId},
    serialization::*,
@@ -15,7 +16,7 @@ use log::{error, trace};
 use zeroize::Zeroizing;

 #[cfg(feature = "untested")]
-use crate::mgm::{MgmKey, DES_LEN_3DES};
+use crate::mgm::{DeviceConfig, DeviceInfo, Lock};

 const CB_PIN_MAX: usize = 8;

@@ -60,26 +61,32 @@ impl<'tx> Transaction<'tx> {
        Ok(recv_buffer)
    }

+    /// Select PIV application.
+    pub fn select_piv_application(&self) -> Result<()> {
+        self.select_application(
+            piv::APPLET_ID,
+            piv::APPLET_NAME,
+            "failed selecting application",
+        )
+    }
+
    /// Select application.
-    pub fn select_application(&self) -> Result<()> {
+    pub fn select_application(
+        &self,
+        applet: &[u8],
+        applet_name: &'static str,
+        error: &'static str,
+    ) -> Result<()> {
        let response = Apdu::new(Ins::SelectApplication)
            .p1(0x04)
-            .data(piv::APPLET_ID)
+            .data(applet)
            .transmit(self, 0xFF)
-            .map_err(|e| {
-                error!("failed communicating with card: '{}'", e);
-                e
-            })?;
+            .inspect_err(|e| error!("failed communicating with card: '{}'", e))?;

        if !response.is_success() {
-            error!(
-                "failed selecting application: {:04x}",
-                response.status_words().code()
-            );
+            error!("{}: {:04x}", error, response.status_words().code());
            return Err(match response.status_words() {
-                StatusWords::NotFoundError => Error::AppletNotFound {
-                    applet_name: piv::APPLET_NAME,
-                },
+                StatusWords::NotFoundError => Error::AppletNotFound { applet_name },
                _ => Error::GenericError,
            });
        }
@@ -92,15 +99,11 @@ impl<'tx> Transaction<'tx> {
        // get version from device
        let response = Apdu::new(Ins::GetVersion).transmit(self, 261)?;

-        if !response.is_success() {
+        if !response.is_success() || response.data().is_empty() {
            return Err(Error::GenericError);
        }

-        if response.data().len() < 3 {
-            return Err(Error::SizeError);
-        }
-
-        Ok(Version::new(response.data()[..3].try_into().unwrap()))
+        Ok(response.data()[..3].try_into().map(Version::new)?)
    }

    /// Get YubiKey device serial number.
@@ -108,21 +111,11 @@ impl<'tx> Transaction<'tx> {
        match version.major {
            // YK4 requires switching to the YK applet to retrieve the serial
            4 => {
-                let sw = Apdu::new(Ins::SelectApplication)
-                    .p1(0x04)
-                    .data(otp::APPLET_ID)
-                    .transmit(self, 0xFF)?
-                    .status_words();
-
-                if !sw.is_success() {
-                    error!("failed selecting yk application: {:04x}", sw.code());
-                    return Err(match sw {
-                        StatusWords::NotFoundError => Error::AppletNotFound {
-                            applet_name: otp::APPLET_NAME,
-                        },
-                        _ => Error::GenericError,
-                    });
-                }
+                self.select_application(
+                    otp::APPLET_ID,
+                    otp::APPLET_NAME,
+                    "failed selecting yk application",
+                )?;

                let response = Apdu::new(0x01).p1(0x10).transmit(self, 0xFF)?;

@@ -136,21 +129,11 @@ impl<'tx> Transaction<'tx> {
                }

                // reselect the PIV applet
-                let sw = Apdu::new(Ins::SelectApplication)
-                    .p1(0x04)
-                    .data(piv::APPLET_ID)
-                    .transmit(self, 0xFF)?
-                    .status_words();
-
-                if !sw.is_success() {
-                    error!("failed selecting application: {:04x}", sw.code());
-                    return Err(match sw {
-                        StatusWords::NotFoundError => Error::AppletNotFound {
-                            applet_name: piv::APPLET_NAME,
-                        },
-                        _ => Error::GenericError,
-                    });
-                }
+                self.select_application(
+                    piv::APPLET_ID,
+                    piv::APPLET_NAME,
+                    "failed selecting application",
+                )?;

                response.data().try_into()
            }
@@ -175,6 +158,24 @@ impl<'tx> Transaction<'tx> {
        }
    }

+    /// Read metadata
+    pub(crate) fn get_metadata(&self, slot: SlotId) -> Result<piv::SlotMetadata> {
+        let response = Apdu::new(Ins::GetMetadata)
+            .p2(slot.into())
+            .transmit(self, CB_OBJ_MAX)?;
+
+        match response.status_words() {
+            StatusWords::Success => {
+                let buf = Buffer::new(response.data().into());
+                piv::SlotMetadata::try_from(buf)
+            }
+            StatusWords::ReferenceDataNotFoundError => Err(Error::NotFound),
+            // Requires firmware 5.2.3
+            StatusWords::NotSupportedError => Err(Error::NotSupported),
+            _ => Err(Error::GenericError),
+        }
+    }
+
    /// Verify device PIN.
    pub fn verify_pin(&self, pin: &[u8]) -> Result<()> {
        if pin.len() > CB_PIN_MAX {
@@ -190,7 +191,7 @@ impl<'tx> Transaction<'tx> {
        if !pin.is_empty() {
            let mut data = Zeroizing::new([0xff; CB_PIN_MAX]);
            data[0..pin.len()].copy_from_slice(pin);
-            query.data(data.as_ref());
+            query.data(data.as_slice());
        }

        let response = query.transmit(self, 261)?;
@@ -247,15 +248,14 @@ impl<'tx> Transaction<'tx> {
    }

    /// Set the management key (MGM).
-    #[cfg(feature = "untested")]
    pub fn set_mgm_key(&self, new_key: &MgmKey, require_touch: bool) -> Result<()> {
        let p2 = if require_touch { 0xfe } else { 0xff };

-        let mut data = [0u8; DES_LEN_3DES + 3];
-        data[0] = ALGO_3DES;
-        data[1] = KEY_CARDMGM;
-        data[2] = DES_LEN_3DES as u8;
-        data[3..3 + DES_LEN_3DES].copy_from_slice(new_key.as_ref());
+        let mut data = Vec::with_capacity(usize::from(new_key.key_size()) + 3);
+        data.push(new_key.algorithm_id().into());
+        data.push(KEY_CARDMGM);
+        data.push(new_key.key_size());
+        data.extend_from_slice(new_key.as_ref());

        let status_words = Apdu::new(Ins::SetMgmKey)
            .params(0xff, p2)
@@ -288,14 +288,23 @@ impl<'tx> Transaction<'tx> {
        let templ = [0, Ins::Authenticate.code(), algorithm.into(), key.into()];

        match algorithm {
-            AlgorithmId::Rsa1024 | AlgorithmId::Rsa2048 => {
-                let key_len = if let AlgorithmId::Rsa1024 = algorithm {
-                    128
-                } else {
-                    256
-                };
-
-                if in_len != key_len {
+            AlgorithmId::Rsa1024 => {
+                if in_len != 128 {
+                    return Err(Error::SizeError);
+                }
+            }
+            AlgorithmId::Rsa2048 => {
+                if in_len != 256 {
+                    return Err(Error::SizeError);
+                }
+            }
+            AlgorithmId::Rsa3072 => {
+                if in_len != 384 {
+                    return Err(Error::SizeError);
+                }
+            }
+            AlgorithmId::Rsa4096 => {
+                if in_len != 512 {
                    return Err(Error::SizeError);
                }
            }
@@ -311,6 +320,19 @@ impl<'tx> Transaction<'tx> {
                    return Err(Error::SizeError);
                }
            }
+            AlgorithmId::X25519 => {
+                if !decipher {
+                    return Err(Error::NotSupported);
+                }
+                if in_len != 32 {
+                    return Err(Error::SizeError);
+                }
+            }
+            AlgorithmId::Ed25519 => {
+                if decipher {
+                    return Err(Error::NotSupported);
+                }
+            }
        }

        let bytes = if in_len < 0x80 {
@@ -327,7 +349,9 @@ impl<'tx> Transaction<'tx> {
                Tlv::write(
                    &mut buf[2..],
                    match (algorithm, decipher) {
-                        (AlgorithmId::EccP256, true) | (AlgorithmId::EccP384, true) => 0x85,
+                        (AlgorithmId::EccP256, true)
+                        | (AlgorithmId::EccP384, true)
+                        | (AlgorithmId::X25519, true) => 0x85,
                        _ => 0x81,
                    },
                    sign_in
@@ -339,10 +363,7 @@ impl<'tx> Transaction<'tx> {

        let response = self
            .transfer_data(&templ, &indata[..offset], 1024)
-            .map_err(|e| {
-                error!("sign command failed to communicate: {}", e);
-                e
-            })?;
+            .inspect_err(|e| error!("sign command failed to communicate: {}", e))?;

        if !response.is_success() {
            error!("failed sign command with code {:x}", response.code());
@@ -515,4 +536,66 @@ impl<'tx> Transaction<'tx> {
            _ => Err(Error::GenericError),
        }
    }
+
+    /// Write configuration to the YubiKey
+    #[cfg(feature = "untested")]
+    pub fn write_config(
+        &mut self,
+        version: Version,
+        config: DeviceConfig,
+        current_lock: Option<Lock>,
+        new_lock: Option<Lock>,
+    ) -> Result<()> {
+        if version
+            < (Version {
+                major: 5,
+                minor: 0,
+                patch: 0,
+            })
+        {
+            return Err(Error::NotSupported);
+        }
+
+        let data = config.as_tlv(true, current_lock, new_lock)?;
+
+        let response = Apdu::new(Ins::WriteConfig)
+            .params(0x00, 0x00)
+            .data(&data)
+            .transmit(self, 2)?;
+
+        if !response.is_success() {
+            error!(
+                "Unable to write_config: {:04x}",
+                response.status_words().code()
+            );
+            return Err(Error::GenericError);
+        }
+
+        Ok(())
+    }
+
+    /// Write configuration to the YubiKey
+    #[cfg(feature = "untested")]
+    pub fn read_config(&mut self) -> Result<DeviceInfo> {
+        let mut data = [0u8; CB_BUF_MAX];
+        let mut len = data.len();
+        let data_remaining = &mut data[..];
+
+        len -= data_remaining.len();
+        let response = Apdu::new(Ins::ReadConfig)
+            .params(0x00, 0x00)
+            .data(&data[..len])
+            .transmit(self, CB_BUF_MAX + 2)?;
+
+        if !response.is_success() {
+            error!(
+                "Unable to read configuration: {:04x}",
+                response.status_words().code()
+            );
+            return Err(Error::GenericError);
+        }
+
+        let data = response.data();
+        DeviceInfo::parse(data)
+    }
 }
@@ -41,10 +41,12 @@ use crate::{
    reader::{Context, Reader},
    transaction::Transaction,
 };
+use cipher::common::getrandom::SysRng;
 use log::{error, info};
-use pcsc::{Card, Disposition};
-use rand_core::{OsRng, RngCore};
+use pcsc::Card;
+use rand_core::TryRng;
 use std::{
+    cmp::{Ord, Ordering},
    fmt::{self, Display},
    str::FromStr,
 };
@@ -59,7 +61,6 @@ use {
        transaction::ChangeRefAction,
        Buffer, ObjectId,
    },
-    secrecy::ExposeSecret,
    std::time::{SystemTime, UNIX_EPOCH},
 };

@@ -67,6 +68,7 @@ use {
 pub(crate) const ADMIN_FLAGS_1_PUK_BLOCKED: u8 = 0x01;

 /// 3DES authentication
+#[cfg(feature = "untested")]
 pub(crate) const ALGO_3DES: u8 = 0x03;

 /// Card management key
@@ -75,10 +77,11 @@ pub(crate) const KEY_CARDMGM: u8 = 0x9b;
 const TAG_DYN_AUTH: u8 = 0x7c;

 /// Cached YubiKey PIN.
-pub type CachedPin = secrecy::SecretVec<u8>;
+// TODO(tarcieri): add a newtype for this with a zeroize impl
+pub type CachedPin = Vec<u8>;

 /// YubiKey serial number.
-#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash, PartialOrd, Ord)]
 pub struct Serial(pub u32);

 impl From<u32> for Serial {
@@ -143,6 +146,22 @@ impl Version {
            patch: bytes[2],
        }
    }
+
+    #[cfg(feature = "untested")]
+    pub(crate) fn parse(input: &[u8]) -> Result<Self> {
+        use nom::{combinator::eof, number::complete::u8};
+
+        let (i, major) = u8(input).map_err(|_: nom::Err<()>| Error::ParseError)?;
+        let (i, minor) = u8(i).map_err(|_: nom::Err<()>| Error::ParseError)?;
+        let (i, patch) = u8(i).map_err(|_: nom::Err<()>| Error::ParseError)?;
+        let (_i, _) = eof(i).map_err(|_: nom::Err<()>| Error::ParseError)?;
+
+        Ok(Self {
+            major,
+            minor,
+            patch,
+        })
+    }
 }

 impl Display for Version {
@@ -151,6 +170,39 @@ impl Display for Version {
    }
 }

+impl Ord for Version {
+    fn cmp(&self, other: &Self) -> Ordering {
+        if self.major > other.major {
+            return Ordering::Greater;
+        }
+        if self.major < other.major {
+            return Ordering::Less;
+        }
+
+        if self.minor > other.minor {
+            return Ordering::Greater;
+        }
+        if self.minor < other.minor {
+            return Ordering::Less;
+        }
+
+        if self.patch > other.patch {
+            return Ordering::Greater;
+        }
+        if self.patch < other.patch {
+            return Ordering::Less;
+        }
+
+        Ordering::Equal
+    }
+}
+
+impl PartialOrd for Version {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
 /// YubiKey device: primary API for opening a session and performing various operations.
 ///
 /// Almost all functionality in this library will require an open session
@@ -178,28 +230,45 @@ impl fmt::Debug for YubiKey {
 impl YubiKey {
    /// Open a connection to a YubiKey.
    ///
-    /// Returns an error if there is more than one YubiKey detected.
+    /// Returns an error if more than one YubiKey is detected (or none at all).
+    ///
+    /// NOTE: If multiple YubiKeys are connected, but we are only able to
+    /// open one of them (e.g. because the other one is in use, and the
+    /// connection doesn't allow sharing), the YubiKey that we were able to
+    /// open is returned.
    ///
    /// If you need to operate in environments with more than one YubiKey
    /// attached to the same system, use [`YubiKey::open_by_serial`] or
    /// [`yubikey::reader::Context`][`Context`] to select from the available
    /// PC/SC readers.
    pub fn open() -> Result<Self> {
-        let mut readers = Context::open()?;
-        let mut reader_iter = readers.iter()?;
+        let mut yubikey: Option<Self> = None;
+
+        let mut readers = Context::open()?;
+        for reader in readers.iter()? {
+            if let Ok(yk_found) = reader.open() {
+                if let Some(yk_stored) = yubikey {
+                    // We found two YubiKeys, so we won't use either.
+                    // Don't reset them.
+                    let _ = yk_stored.disconnect(pcsc::Disposition::LeaveCard);
+                    let _ = yk_found.disconnect(pcsc::Disposition::LeaveCard);

-        if let Some(reader) = reader_iter.next() {
-            if reader_iter.next().is_some() {
                    error!("multiple YubiKeys detected!");
                    return Err(Error::PcscError { inner: None });
+                } else {
+                    yubikey = Some(yk_found);
+                }
+            }
        }

-            return reader.open();
-        }
-
+        if let Some(yubikey) = yubikey {
+            // We found exactly one YubiKey that we could open, so we return it.
+            Ok(yubikey)
+        } else {
            error!("no YubiKey detected!");
            Err(Error::NotFound)
        }
+    }

    /// Open a YubiKey with a specific serial number.
    pub fn open_by_serial(serial: Serial) -> Result<Self> {
@@ -243,7 +312,6 @@ impl YubiKey {

    /// Reconnect to a YubiKey.
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn reconnect(&mut self) -> Result<()> {
        info!("trying to reconnect to current reader");

@@ -253,13 +321,10 @@ impl YubiKey {
            pcsc::Disposition::ResetCard,
        )?;

-        let pin = self
-            .pin
-            .as_ref()
-            .map(|p| Buffer::new(p.expose_secret().clone()));
+        let pin = self.pin.as_ref().map(|p| Buffer::new(p.clone()));

        let txn = Transaction::new(&mut self.card)?;
-        txn.select_application()?;
+        txn.select_piv_application()?;

        if let Some(p) = &pin {
            txn.verify_pin(p)?;
@@ -277,7 +342,10 @@ impl YubiKey {
    /// `YubiKey` implements `Drop` which automatically disconnects the card using
    /// `Disposition::ResetCard`; you only need to call this function if you want to
    /// handle errors or use a different disposition method.
-    pub fn disconnect(self, disposition: Disposition) -> core::result::Result<(), (Self, Error)> {
+    pub fn disconnect(
+        self,
+        disposition: pcsc::Disposition,
+    ) -> core::result::Result<(), (Self, Error)> {
        let Self {
            card,
            name,
@@ -341,37 +409,46 @@ impl YubiKey {
    }

    /// Authenticate to the card using the provided management key (MGM).
-    pub fn authenticate(&mut self, mgm_key: MgmKey) -> Result<()> {
+    pub fn authenticate(&mut self, mgm_key: &MgmKey) -> Result<()> {
        let txn = self.begin_transaction()?;

        // get a challenge from the card
-        let challenge = Apdu::new(Ins::Authenticate)
-            .params(ALGO_3DES, KEY_CARDMGM)
+        let card_response = Apdu::new(Ins::Authenticate)
+            .params(mgm_key.algorithm_id().into(), KEY_CARDMGM)
            .data([TAG_DYN_AUTH, 0x02, 0x80, 0x00])
            .transmit(&txn, 261)?;

-        if !challenge.is_success() || challenge.data().len() < 12 {
+        if !card_response.is_success() || card_response.data().len() < 5 {
            return Err(Error::AuthenticationError);
        }

        // send a response to the cards challenge and a challenge of our own.
-        let response = mgm_key.decrypt(challenge.data()[4..12].try_into().unwrap());
+        let card_challenge = mgm_key.card_challenge(&card_response.data()[4..])?;
+        let challenge_len = card_challenge.len();

-        let mut data = [0u8; 22];
-        data[0] = TAG_DYN_AUTH;
-        data[1] = 20; // 2 + 8 + 2 +8
-        data[2] = 0x80;
-        data[3] = 8;
-        data[4..12].copy_from_slice(&response);
-        data[12] = 0x81;
-        data[13] = 8;
-        OsRng.fill_bytes(&mut data[14..22]);
+        // If this exceeds a `u8` then the card is giving us unexpected data.
+        let auth_len = (2 + challenge_len + 2 + challenge_len)
+            .try_into()
+            .map_err(|_| Error::AuthenticationError)?;

-        let mut challenge = [0u8; 8];
-        challenge.copy_from_slice(&data[14..22]);
+        let mut data = Vec::with_capacity(4 + challenge_len + 2 + challenge_len);
+        data.push(TAG_DYN_AUTH);
+        data.push(auth_len);
+        data.push(0x80);
+        data.push(challenge_len as u8);
+        data.extend_from_slice(&card_challenge);
+        data.push(0x81);
+        data.push(challenge_len as u8);
+
+        let mut host_challenge = vec![0u8; challenge_len];
+        SysRng
+            .try_fill_bytes(&mut host_challenge)
+            .map_err(|_| Error::GenericError)?;
+
+        data.extend_from_slice(&host_challenge);

        let authentication = Apdu::new(Ins::Authenticate)
-            .params(ALGO_3DES, KEY_CARDMGM)
+            .params(mgm_key.algorithm_id().into(), KEY_CARDMGM)
            .data(data)
            .transmit(&txn, 261)?;

@@ -380,14 +457,7 @@ impl YubiKey {
        }

        // compare the response from the card with our challenge
-        let response = mgm_key.encrypt(&challenge);
-
-        use subtle::ConstantTimeEq;
-        if response.ct_eq(&authentication.data()[4..12]).unwrap_u8() != 1 {
-            return Err(Error::AuthenticationError);
-        }
-
-        Ok(())
+        mgm_key.check_challenge(&host_challenge, &authentication.data()[4..])
    }

    /// Get the PIV keys contained in this YubiKey.
@@ -397,7 +467,6 @@ impl YubiKey {

    /// Deauthenticate.
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn deauthenticate(&mut self) -> Result<()> {
        let txn = self.begin_transaction()?;

@@ -431,7 +500,7 @@ impl YubiKey {
        }

        if !pin.is_empty() {
-            self.pin = Some(CachedPin::new(pin.into()))
+            self.pin = Some(pin.into())
        }

        Ok(())
@@ -444,7 +513,7 @@ impl YubiKey {
        // Force a re-select to unverify, because once verified the spec dictates that
        // subsequent verify calls will return a "verification not needed" instead of
        // the number of tries left...
-        txn.select_application()?;
+        txn.select_piv_application()?;

        // WRONG_PIN is expected on successful query.
        match txn.verify_pin(&[]) {
@@ -456,7 +525,6 @@ impl YubiKey {

    /// Set the number of PIN retries.
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn set_pin_retries(&mut self, pin_tries: u8, puk_tries: u8) -> Result<()> {
        // Special case: if either retry count is 0, it's a successful no-op
        if pin_tries == 0 || puk_tries == 0 {
@@ -481,7 +549,6 @@ impl YubiKey {
    ///
    /// The default PIN code is `123456`.
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn change_pin(&mut self, current_pin: &[u8], new_pin: &[u8]) -> Result<()> {
        {
            let txn = self.begin_transaction()?;
@@ -489,7 +556,7 @@ impl YubiKey {
        }

        if !new_pin.is_empty() {
-            self.pin = Some(CachedPin::new(new_pin.into()));
+            self.pin = Some(new_pin.into());
        }

        Ok(())
@@ -497,7 +564,6 @@ impl YubiKey {

    /// Set PIN last changed.
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn set_pin_last_changed(yubikey: &mut YubiKey) -> Result<()> {
        let txn = yubikey.begin_transaction()?;

@@ -505,22 +571,17 @@ impl YubiKey {

        // TODO(tarcieri): double check this is little endian
        let tnow = SystemTime::now()
-            .duration_since(UNIX_EPOCH)
-            .unwrap()
+            .duration_since(UNIX_EPOCH)?
            .as_secs()
            .to_le_bytes();

        admin_data
            .set_item(TAG_ADMIN_TIMESTAMP, &tnow)
-            .map_err(|e| {
-                error!("could not set pin timestamp, err = {}", e);
-                e
-            })?;
+            .inspect_err(|e| error!("could not set pin timestamp, err = {}", e))?;

-        admin_data.write(&txn).map_err(|e| {
-            error!("could not write admin data, err = {}", e);
-            e
-        })?;
+        admin_data
+            .write(&txn)
+            .inspect_err(|e| error!("could not write admin data, err = {}", e))?;

        Ok(())
    }
@@ -533,7 +594,6 @@ impl YubiKey {
    ///
    /// The default PUK code is `12345678`.
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn change_puk(&mut self, current_puk: &[u8], new_puk: &[u8]) -> Result<()> {
        let txn = self.begin_transaction()?;
        txn.change_ref(ChangeRefAction::ChangePuk, current_puk, new_puk)
@@ -541,7 +601,6 @@ impl YubiKey {

    /// Block PUK: permanently prevent the PIN from becoming unblocked.
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn block_puk(&mut self) -> Result<()> {
        let mut puk = [0x30, 0x42, 0x41, 0x44, 0x46, 0x30, 0x30, 0x44];
        let mut tries_remaining: i32 = -1;
@@ -572,7 +631,7 @@ impl YubiKey {

        // Attempt to set the "PUK blocked" flag in admin data.
        let mut admin_data = AdminData::read(&txn)
-            .map(|data| {
+            .inspect(|data| {
                if let Ok(item) = data.get_item(TAG_ADMIN_FLAGS_1) {
                    if item.len() == flags.len() {
                        flags.copy_from_slice(item)
@@ -584,8 +643,6 @@ impl YubiKey {
                        );
                    }
                }
-
-                data
            })
            .unwrap_or_default();

@@ -605,7 +662,6 @@ impl YubiKey {
    /// Unblock a Personal Identification Number (PIN) using a previously
    /// configured PIN Unblocking Key (PUK).
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn unblock_pin(&mut self, puk: &[u8], new_pin: &[u8]) -> Result<()> {
        let txn = self.begin_transaction()?;
        txn.change_ref(ChangeRefAction::UnblockPin, puk, new_pin)
@@ -613,7 +669,6 @@ impl YubiKey {

    /// Fetch an object from the YubiKey.
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn fetch_object(&mut self, object_id: ObjectId) -> Result<Buffer> {
        let txn = self.begin_transaction()?;
        txn.fetch_object(object_id)
@@ -621,7 +676,6 @@ impl YubiKey {

    /// Save an object.
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn save_object(&mut self, object_id: ObjectId, indata: &mut [u8]) -> Result<()> {
        let txn = self.begin_transaction()?;
        txn.save_object(object_id, indata)
@@ -629,7 +683,6 @@ impl YubiKey {

    /// Get an auth challenge.
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn get_auth_challenge(&mut self) -> Result<[u8; 8]> {
        let txn = self.begin_transaction()?;

@@ -642,12 +695,15 @@ impl YubiKey {
            return Err(Error::AuthenticationError);
        }

-        Ok(response.data()[4..12].try_into().unwrap())
+        Ok(response
+            .data()
+            .get(4..12)
+            .ok_or(Error::SizeError)?
+            .try_into()?)
    }

    /// Verify an auth response.
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn verify_auth_response(&mut self, response: [u8; 8]) -> Result<()> {
        let mut data = [0u8; 12];
        data[0] = 0x7c;
@@ -678,7 +734,6 @@ impl YubiKey {
    ///
    /// The reset function is only available when both pins are blocked.
    #[cfg(feature = "untested")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "untested")))]
    pub fn reset_device(&mut self) -> Result<()> {
        let templ = [0, Ins::Reset.code(), 0, 0];
        let txn = self.begin_transaction()?;
@@ -696,16 +751,15 @@ impl<'a> TryFrom<&'a Reader<'_>> for YubiKey {
    type Error = Error;

    fn try_from(reader: &'a Reader<'_>) -> Result<Self> {
-        let mut card = reader.connect().map_err(|e| {
-            error!("error connecting to reader '{}': {}", reader.name(), e);
-            e
-        })?;
+        let mut card = reader
+            .connect()
+            .inspect_err(|e| error!("error connecting to reader '{}': {}", reader.name(), e))?;

        info!("connected to reader: {}", reader.name());

        let mut app_version_serial = || -> Result<(Version, Serial)> {
            let txn = Transaction::new(&mut card)?;
-            txn.select_application()?;
+            txn.select_piv_application()?;

            let v = txn.get_version()?;
            let s = txn.get_serial(v)?;
@@ -3,17 +3,16 @@
 #![forbid(unsafe_code)]
 #![warn(missing_docs, rust_2018_idioms, trivial_casts, unused_qualifications)]

+use cipher::common::{getrandom::SysRng, Generate};
 use log::trace;
 use once_cell::sync::Lazy;
-use rand_core::{OsRng, RngCore};
-use rsa::pkcs1v15;
+use rsa::{pkcs1v15, RsaPublicKey};
 use sha2::{Digest, Sha256};
 use signature::hazmat::PrehashVerifier;
-use std::{env, str::FromStr, sync::Mutex};
-use x509::RelativeDistinguishedName;
+use std::{env, str::FromStr, sync::Mutex, time::Duration};
+use x509_cert::{der::Encode, name::Name, serial_number::SerialNumber, time::Validity};
 use yubikey::{
-    certificate,
-    certificate::{Certificate, PublicKeyInfo},
+    certificate::{yubikey_signer, Certificate},
    piv::{self, AlgorithmId, Key, ManagementSlotId, RetiredSlotId, SlotId},
    Error, MgmKey, PinPolicy, Serial, TouchPolicy, YubiKey,
 };
@@ -44,12 +43,15 @@ static YUBIKEY: Lazy<Mutex<YubiKey>> = Lazy::new(|| {
 #[test]
 #[ignore]
 fn test_get_cccid() {
-    let mut yubikey = YUBIKEY.lock().unwrap();
+    let mut yubikey = match YUBIKEY.lock() {
+        Ok(yubikey) => yubikey,
+        Err(poison) => poison.into_inner(),
+    };

    match yubikey.cccid() {
        Ok(cccid) => trace!("CCCID: {:?}", cccid),
        Err(Error::NotFound) => trace!("CCCID not found"),
-        Err(err) => panic!("error getting CCCID: {:?}", err),
+        Err(err) => panic!("error getting CCCID: {err:?}"),
    }
 }

@@ -60,12 +62,15 @@ fn test_get_cccid() {
 #[test]
 #[ignore]
 fn test_get_chuid() {
-    let mut yubikey = YUBIKEY.lock().unwrap();
+    let mut yubikey = match YUBIKEY.lock() {
+        Ok(yubikey) => yubikey,
+        Err(poison) => poison.into_inner(),
+    };

    match yubikey.chuid() {
        Ok(chuid) => trace!("CHUID: {:?}", chuid),
        Err(Error::NotFound) => trace!("CHUID not found"),
-        Err(err) => panic!("error getting CHUID: {:?}", err),
+        Err(err) => panic!("error getting CHUID: {err:?}"),
    }
 }

@@ -76,7 +81,10 @@ fn test_get_chuid() {
 #[test]
 #[ignore]
 fn test_get_config() {
-    let mut yubikey = YUBIKEY.lock().unwrap();
+    let mut yubikey = match YUBIKEY.lock() {
+        Ok(yubikey) => yubikey,
+        Err(poison) => poison.into_inner(),
+    };
    let config_result = yubikey.config();
    assert!(config_result.is_ok());
    trace!("config: {:?}", config_result.unwrap());
@@ -89,7 +97,10 @@ fn test_get_config() {
 #[test]
 #[ignore]
 fn test_list_keys() {
-    let mut yubikey = YUBIKEY.lock().unwrap();
+    let mut yubikey = match YUBIKEY.lock() {
+        Ok(yubikey) => yubikey,
+        Err(poison) => poison.into_inner(),
+    };
    let keys_result = Key::list(&mut yubikey);
    assert!(keys_result.is_ok());
    trace!("keys: {:?}", keys_result.unwrap());
@@ -102,7 +113,10 @@ fn test_list_keys() {
 #[test]
 #[ignore]
 fn test_verify_pin() {
-    let mut yubikey = YUBIKEY.lock().unwrap();
+    let mut yubikey = match YUBIKEY.lock() {
+        Ok(yubikey) => yubikey,
+        Err(poison) => poison.into_inner(),
+    };
    assert!(yubikey.verify_pin(b"000000").is_err());
    assert!(yubikey.verify_pin(b"123456").is_ok());
 }
@@ -115,43 +129,52 @@ fn test_verify_pin() {
 #[test]
 #[ignore]
 fn test_set_mgmkey() {
-    let mut yubikey = YUBIKEY.lock().unwrap();
+    let mut rng = SysRng;
+    let mut yubikey = match YUBIKEY.lock() {
+        Ok(yubikey) => yubikey,
+        Err(poison) => poison.into_inner(),
+    };
+    let default_key = MgmKey::get_default(&yubikey).unwrap();

    assert!(yubikey.verify_pin(b"123456").is_ok());
    assert!(MgmKey::get_protected(&mut yubikey).is_err());
-    assert!(yubikey.authenticate(MgmKey::default()).is_ok());
+    assert!(yubikey.authenticate(&default_key).is_ok());

    // Set a protected management key.
-    assert!(MgmKey::generate().set_protected(&mut yubikey).is_ok());
+    assert!(MgmKey::generate_for(&yubikey, &mut rng)
+        .unwrap()
+        .set_protected(&mut yubikey)
+        .is_ok());
    let protected = MgmKey::get_protected(&mut yubikey).unwrap();
-    assert!(yubikey.authenticate(MgmKey::default()).is_err());
-    assert!(yubikey.authenticate(protected.clone()).is_ok());
+    assert!(yubikey.authenticate(&default_key).is_err());
+    assert!(yubikey.authenticate(&protected).is_ok());

    // Set a manual management key.
-    let manual = MgmKey::generate();
+    let manual = MgmKey::generate_for(&yubikey, &mut rng).unwrap();
    assert!(manual.set_manual(&mut yubikey, false).is_ok());
    assert!(MgmKey::get_protected(&mut yubikey).is_err());
-    assert!(yubikey.authenticate(MgmKey::default()).is_err());
-    assert!(yubikey.authenticate(protected.clone()).is_err());
-    assert!(yubikey.authenticate(manual.clone()).is_ok());
+    assert!(yubikey.authenticate(&default_key).is_err());
+    assert!(yubikey.authenticate(&protected).is_err());
+    assert!(yubikey.authenticate(&manual).is_ok());

    // Set back to the default management key.
    assert!(MgmKey::set_default(&mut yubikey).is_ok());
    assert!(MgmKey::get_protected(&mut yubikey).is_err());
-    assert!(yubikey.authenticate(protected).is_err());
-    assert!(yubikey.authenticate(manual).is_err());
-    assert!(yubikey.authenticate(MgmKey::default()).is_ok());
+    assert!(yubikey.authenticate(&protected).is_err());
+    assert!(yubikey.authenticate(&manual).is_err());
+    assert!(yubikey.authenticate(&default_key).is_ok());
 }

 //
 // Certificate support
 //

-fn generate_self_signed_cert(algorithm: AlgorithmId) -> Certificate {
+fn generate_self_signed_cert<KT: yubikey_signer::KeyType>() -> Certificate {
    let mut yubikey = YUBIKEY.lock().unwrap();
+    let default_key = MgmKey::get_default(&yubikey).unwrap();

    assert!(yubikey.verify_pin(b"123456").is_ok());
-    assert!(yubikey.authenticate(MgmKey::default()).is_ok());
+    assert!(yubikey.authenticate(&default_key).is_ok());

    let slot = SlotId::Retired(RetiredSlotId::R1);

@@ -159,25 +182,27 @@ fn generate_self_signed_cert(algorithm: AlgorithmId) -> Certificate {
    let generated = piv::generate(
        &mut yubikey,
        slot,
-        algorithm,
+        KT::ALGORITHM,
        PinPolicy::Default,
        TouchPolicy::Default,
    )
    .unwrap();

-    let mut serial = [0u8; 20];
-    OsRng.fill_bytes(&mut serial);
+    // 0x80 0x00 ... (20bytes) is invalid because of high MSB (serial will keep the sign)
+    // we'll limit ourselves to 19 bytes serial.
+    let serial = <[u8; 19]>::generate();
+    let serial = SerialNumber::new(&serial[..]).expect("serial can't be more than 20 bytes long");
+    let validity = Validity::from_now(Duration::new(500000, 0)).unwrap();

    // Generate a self-signed certificate for the new key.
-    let extensions: &[x509::Extension<'_, &[u64]>] = &[];
-    let cert_result = Certificate::generate_self_signed(
+    let cert_result = Certificate::generate_self_signed::<_, KT>(
        &mut yubikey,
        slot,
        serial,
-        None,
-        &[RelativeDistinguishedName::common_name("testSubject")],
+        validity,
+        Name::from_str("CN=testSubject").expect("parse name"),
        generated,
-        extensions,
+        |_builder| Ok(()),
    );

    assert!(cert_result.is_ok());
@@ -189,18 +214,16 @@ fn generate_self_signed_cert(algorithm: AlgorithmId) -> Certificate {
 #[test]
 #[ignore]
 fn generate_self_signed_rsa_cert() {
-    let cert = generate_self_signed_cert(AlgorithmId::Rsa1024);
+    let cert = generate_self_signed_cert::<yubikey_signer::YubiRsa<yubikey_signer::Rsa1024>>();

    //
    // Verify that the certificate is signed correctly
    //

-    let pubkey = match cert.subject_pki() {
-        PublicKeyInfo::Rsa { pubkey, .. } => pkcs1v15::VerifyingKey::<Sha256>::from(pubkey.clone()),
-        _ => unreachable!(),
-    };
+    let pubkey = RsaPublicKey::try_from(cert.subject_pki()).expect("valid rsa key");
+    let pubkey = pkcs1v15::VerifyingKey::<Sha256>::new(pubkey);

-    let data = cert.as_ref();
+    let data = cert.cert.to_der().expect("serialize certificate");
    let tbs_cert_len = u16::from_be_bytes(data[6..8].try_into().unwrap()) as usize;
    let msg = &data[4..8 + tbs_cert_len];
    let sig = pkcs1v15::Signature::try_from(&data[data.len() - 128..]).unwrap();
@@ -209,32 +232,82 @@ fn generate_self_signed_rsa_cert() {
    assert!(pubkey.verify_prehash(&hash, &sig).is_ok());
 }

+#[test]
+#[ignore]
+fn generate_rsa3072() {
+    let mut yubikey = YUBIKEY.lock().unwrap();
+    let version = yubikey.version();
+    let default_key = MgmKey::get_default(&yubikey).unwrap();
+
+    assert!(yubikey.authenticate(&default_key).is_ok());
+
+    let slot = SlotId::Retired(RetiredSlotId::R1);
+
+    // Generate a new key in the selected slot.
+    let generated = piv::generate(
+        &mut yubikey,
+        slot,
+        AlgorithmId::Rsa3072,
+        PinPolicy::Default,
+        TouchPolicy::Default,
+    );
+
+    match generated {
+        Ok(key) => {
+            let pubkey = key.subject_public_key;
+            assert!(pubkey.bit_len() > 3072)
+        }
+        Err(e) => assert!((version.major, version.minor) < (5, 7) && e == Error::AlgorithmError),
+    }
+}
+
 #[test]
 #[ignore]
 fn generate_self_signed_ec_cert() {
-    let cert = generate_self_signed_cert(AlgorithmId::EccP256);
+    let cert = generate_self_signed_cert::<p256::NistP256>();

    //
    // Verify that the certificate is signed correctly
    //

-    let pubkey = match cert.subject_pki() {
-        PublicKeyInfo::EcP256(pubkey) => pubkey,
-        _ => unreachable!(),
-    };
+    let vk = p256::ecdsa::VerifyingKey::try_from(cert.subject_pki()).expect("ecdsa key expected");

-    let data = cert.as_ref();
+    let data = cert.cert.to_der().expect("serialize certificate");
    let tbs_cert_len = data[6] as usize;
    let sig_algo_len = data[7 + tbs_cert_len + 1] as usize;
    let sig_start = 7 + tbs_cert_len + 2 + sig_algo_len + 3;
    let msg = &data[4..7 + tbs_cert_len];
    let sig = p256::ecdsa::Signature::from_der(&data[sig_start..]).unwrap();
-    let vk = p256::ecdsa::VerifyingKey::from_sec1_bytes(pubkey.as_bytes()).unwrap();

    use p256::ecdsa::signature::Verifier;
    assert!(vk.verify(msg, &sig).is_ok());
 }

+#[test]
+#[ignore]
+fn generate_self_signed_cv_cert() {
+    let cert = generate_self_signed_cert::<ed25519_dalek::SigningKey>();
+
+    //
+    // Verify that the certificate is signed correctly
+    //
+
+    let pubkey =
+        ed25519_dalek::VerifyingKey::try_from(cert.subject_pki()).expect("ed25519 key expected");
+
+    let data = cert.cert.to_der().expect("serialize certificate");
+    let cert_len = data[2] as usize;
+    let tbs_cert_len = data[5] as usize;
+    let sig_algo_len: usize = 64;
+    let sig_start = cert_len - sig_algo_len + 3;
+    let msg = &data[3..6 + tbs_cert_len];
+    let sig =
+        ed25519_dalek::Signature::from_slice(&data[sig_start..sig_start + sig_algo_len]).unwrap();
+
+    use ed25519_dalek::Verifier;
+    assert!(pubkey.verify(msg, &sig).is_ok());
+}
+
 #[test]
 #[ignore]
 fn test_slot_id_display() {
@@ -269,11 +342,11 @@ fn test_slot_id_display() {

    assert_eq!(
        format!("{}", SlotId::Management(ManagementSlotId::Pin)),
-        "PIN"
+        "Pin"
    );
    assert_eq!(
        format!("{}", SlotId::Management(ManagementSlotId::Puk)),
-        "PUK"
+        "Puk"
    );
    assert_eq!(
        format!("{}", SlotId::Management(ManagementSlotId::Management)),
@@ -288,10 +361,14 @@ fn test_slot_id_display() {
 #[test]
 #[ignore]
 fn test_read_metadata() {
-    let mut yubikey = YUBIKEY.lock().unwrap();
+    let mut yubikey = match YUBIKEY.lock() {
+        Ok(yubikey) => yubikey,
+        Err(poison) => poison.into_inner(),
+    };
+    let default_key = MgmKey::get_default(&yubikey).unwrap();

    assert!(yubikey.verify_pin(b"123456").is_ok());
-    assert!(yubikey.authenticate(MgmKey::default()).is_ok());
+    assert!(yubikey.authenticate(&default_key).is_ok());

    let slot = SlotId::Retired(RetiredSlotId::R1);

@@ -305,61 +382,68 @@ fn test_read_metadata() {
    )
    .unwrap();

-    let metadata = piv::metadata(&mut yubikey, slot).unwrap();
-
-    assert_eq!(metadata.public, Some(generated));
+    match piv::metadata(&mut yubikey, slot) {
+        Ok(metadata) => assert_eq!(metadata.public, Some(generated)),
+        Err(Error::NotSupported) => {
+            // Some YubiKeys don't support metadata
+            eprintln!("metadata not supported by this YubiKey");
+        }
+        Err(err) => panic!("{}", err),
+    }
 }

 #[test]
 #[ignore]
-fn test_serial_string_conversions() {
-    //2^152+1
-    let serial: [u8; 20] = [
-        0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-        0x00, 0x00, 0x00, 0x00, 0x01,
+fn test_read_metadata_missing_key() {
+    let mut yubikey = YUBIKEY.lock().unwrap();
+    let default_key = MgmKey::get_default(&yubikey).unwrap();
+
+    assert!(yubikey.verify_pin(b"123456").is_ok());
+    assert!(yubikey.authenticate(&default_key).is_ok());
+
+    // we assume that at least one of these slots is empty
+    let slots_to_check = [
+        RetiredSlotId::R10,
+        RetiredSlotId::R11,
+        RetiredSlotId::R12,
+        RetiredSlotId::R13,
+        RetiredSlotId::R14,
+        RetiredSlotId::R15,
+        RetiredSlotId::R16,
+        RetiredSlotId::R17,
+        RetiredSlotId::R18,
+        RetiredSlotId::R19,
+        RetiredSlotId::R20,
    ];

-    let s = certificate::Serial::from(serial);
-    assert_eq!(
-        s.as_x509_int(),
-        "5708990770823839524233143877797980545530986497"
-    );
-    assert_eq!(
-        s.as_x509_hex(),
-        "01:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:01"
-    );
+    for slot in slots_to_check {
+        let slot = SlotId::Retired(slot);

-    let serial2: [u8; 20] = [
-        0xA1, 0xF3, 0x02, 0x30, 0x76, 0x01, 0x32, 0x48, 0x09, 0x9C, 0x10, 0xAA, 0x3F, 0xA0, 0x54,
-        0x0D, 0xC0, 0xB7, 0x65, 0x01,
-    ];
+        match piv::metadata(&mut yubikey, slot) {
+            Ok(_) => {
+                eprintln!("Key {} exists", slot);
+            }
+            Err(Error::NotSupported) => {
+                // Some YubiKeys don't support metadata
+                eprintln!("metadata not supported by this YubiKey");
+                return;
+            }
+            Err(Error::NotFound) => {
+                eprintln!("Key {} doesn't exist, ok.", slot);
+                return;
+            }
+            Err(err) => panic!("{}", err),
+        }
+    }

-    let s2 = certificate::Serial::from(serial2);
-    assert_eq!(
-        s2.as_x509_int(),
-        "924566785900861696177829411010986812227211191553"
-    );
-    assert_eq!(
-        s2.as_x509_hex(),
-        "a1:f3:02:30:76:01:32:48:09:9c:10:aa:3f:a0:54:0d:c0:b7:65:01"
-    );
-
-    let serial3: [u8; 20] = [
-        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xAA, 0x3F, 0xA0, 0x54,
-        0x0D, 0xC0, 0xB7, 0x65, 0x01,
-    ];
-
-    let s3 = certificate::Serial::from(serial3);
-    assert_eq!(s3.as_x509_int(), "3140531249369331492097");
-    assert_eq!(s3.as_x509_hex(), "aa:3f:a0:54:0d:c0:b7:65:01");
+    panic!("No empty slots to check");
 }

 #[test]
 #[ignore]
 fn test_parse_cert_from_der() {
    let bob_der = std::fs::read("tests/assets/Bob.der").expect(".der file not found");
-    let cert =
-        certificate::Certificate::from_bytes(bob_der).expect("Failed to parse valid certificate");
+    let cert = Certificate::from_bytes(bob_der).expect("Failed to parse valid certificate");
    assert_eq!(
        cert.subject(),
        "CN=Bob",