Jack Grigg
69 lines
2.1 KiB
Rust
69 lines
2.1 KiB
Rust
use bech32::{ToBase32, Variant};
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use p256::elliptic_curve::sec1::{FromEncodedPoint, ToEncodedPoint};
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use sha2::{Digest, Sha256};
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use std::convert::TryInto;
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use std::fmt;
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use crate::RECIPIENT_PREFIX;
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pub(crate) const TAG_BYTES: usize = 4;
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/// Wrapper around a compressed secp256r1 curve point.
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#[derive(Clone)]
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pub struct Recipient(p256::PublicKey);
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impl fmt::Debug for Recipient {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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write!(f, "Recipient({:?})", self.to_encoded().as_bytes())
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}
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}
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impl fmt::Display for Recipient {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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f.write_str(
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bech32::encode(
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RECIPIENT_PREFIX,
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self.to_encoded().as_bytes().to_base32(),
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Variant::Bech32,
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)
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.expect("HRP is valid")
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.as_str(),
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)
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}
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}
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impl Recipient {
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/// Attempts to parse a valid YubiKey recipient from its compressed SEC-1 byte encoding.
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pub(crate) fn from_bytes(bytes: &[u8]) -> Option<Self> {
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let encoded = p256::EncodedPoint::from_bytes(bytes).ok()?;
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if encoded.is_compressed() {
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Self::from_encoded(&encoded)
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} else {
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None
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}
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}
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/// Attempts to parse a valid YubiKey recipient from its SEC-1 encoding.
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///
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/// This accepts both compressed (as used by the plugin) and uncompressed (as used in
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/// the YubiKey certificate) encodings.
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pub(crate) fn from_encoded(encoded: &p256::EncodedPoint) -> Option<Self> {
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p256::PublicKey::from_encoded_point(encoded).map(Recipient)
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}
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/// Returns the compressed SEC-1 encoding of this recipient.
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pub(crate) fn to_encoded(&self) -> p256::EncodedPoint {
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self.0.to_encoded_point(true)
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}
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pub(crate) fn tag(&self) -> [u8; TAG_BYTES] {
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let tag = Sha256::digest(self.to_encoded().as_bytes());
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(&tag[0..TAG_BYTES]).try_into().expect("length is correct")
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}
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/// Exposes the wrapped public key.
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pub(crate) fn public_key(&self) -> &p256::PublicKey {
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&self.0
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}
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}
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