crypto/
p256.rs

1// SPDX-License-Identifier: Apache-2.0
2//! P-256 (ECDSA) signature implementation.
3
4use p256::{
5    SecretKey,
6    ecdsa::{
7        Signature, SigningKey, VerifyingKey,
8        signature::{Signer as SignatureSigner, Verifier as SignatureVerifier},
9    },
10    elliptic_curve::Generate,
11    pkcs8::{DecodePrivateKey, EncodePrivateKey, LineEnding},
12};
13
14use crate::{Signer, SignerError};
15
16/// P-256 (ECDSA) signer.
17pub struct P256Signer {
18    signing_key: SigningKey,
19    cached_public_key: Vec<u8>,
20}
21
22impl P256Signer {
23    fn from_signing_key(signing_key: SigningKey) -> Self {
24        let cached_public_key = signing_key
25            .verifying_key()
26            .to_sec1_point(false)
27            .as_bytes()
28            .to_vec();
29        Self {
30            signing_key,
31            cached_public_key,
32        }
33    }
34
35    pub fn generate() -> Result<Self, SignerError> {
36        let signing_key =
37            SigningKey::try_generate().map_err(|e| SignerError::P256(e.to_string()))?;
38        Ok(Self::from_signing_key(signing_key))
39    }
40
41    pub fn from_pem(pem: &str) -> Result<Self, SignerError> {
42        if let Ok(signing_key) = SigningKey::from_pkcs8_pem(pem) {
43            return Ok(Self::from_signing_key(signing_key));
44        }
45
46        if let Ok(ec_sk) = SecretKey::from_sec1_pem(pem) {
47            return Ok(Self::from_signing_key(SigningKey::from(ec_sk)));
48        }
49
50        Err(SignerError::UnknownKeyFormat)
51    }
52
53    pub fn to_pem(&self) -> Result<String, SignerError> {
54        self.signing_key
55            .to_pkcs8_pem(LineEnding::LF)
56            .map(|pem| pem.to_string())
57            .map_err(|e| SignerError::Pkcs8(e.to_string()))
58    }
59
60    pub fn verify_with_public_key(
61        data: &[u8],
62        public_key: &[u8],
63        signature: &[u8],
64    ) -> Result<(), SignerError> {
65        let verifying_key = VerifyingKey::from_sec1_bytes(public_key)
66            .map_err(|e| SignerError::InvalidPublicKey(e.to_string()))?;
67        if let Ok(signature) = Signature::from_slice(signature) {
68            return verifying_key
69                .verify(data, &signature)
70                .map_err(|_| SignerError::VerificationFailed);
71        }
72        let signature = Signature::from_der(signature)
73            .map_err(|e| SignerError::InvalidSignature(e.to_string()))?;
74        verifying_key
75            .verify(data, &signature)
76            .map_err(|_| SignerError::VerificationFailed)
77    }
78}
79
80impl Signer for P256Signer {
81    fn algorithm(&self) -> &'static str {
82        "p256"
83    }
84
85    fn public_key(&self) -> &[u8] {
86        &self.cached_public_key
87    }
88
89    fn sign(&self, data: &[u8]) -> Result<Vec<u8>, SignerError> {
90        let signature: Signature = self.signing_key.sign(data);
91        Ok(signature.to_bytes().to_vec())
92    }
93
94    fn verify(&self, data: &[u8], signature: &[u8]) -> Result<(), SignerError> {
95        Self::verify_with_public_key(data, self.public_key(), signature)
96    }
97}
crypto/p256.rs

crypto/
p256.rs
