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use std::sync::Arc;
use base64;
use ring::{rand, digest, hmac, signature};
use ring::constant_time::verify_slices_are_equal;
use untrusted;
use errors::{Result, ErrorKind};
#[derive(Debug, PartialEq, Copy, Clone, Serialize, Deserialize)]
pub enum Algorithm {
HS256,
HS384,
HS512,
RS256,
RS384,
RS512,
}
fn sign_hmac(alg: &'static digest::Algorithm, key: &[u8], signing_input: &str) -> Result<String> {
let signing_key = hmac::SigningKey::new(alg, key);
let digest = hmac::sign(&signing_key, signing_input.as_bytes());
Ok(
base64::encode_config::<hmac::Signature>(&digest, base64::URL_SAFE_NO_PAD)
)
}
fn sign_rsa(alg: Algorithm, key: &[u8], signing_input: &str) -> Result<String> {
let ring_alg = match alg {
Algorithm::RS256 => &signature::RSA_PKCS1_SHA256,
Algorithm::RS384 => &signature::RSA_PKCS1_SHA384,
Algorithm::RS512 => &signature::RSA_PKCS1_SHA512,
_ => unreachable!(),
};
let key_pair = Arc::new(
signature::RSAKeyPair::from_der(untrusted::Input::from(key))
.map_err(|_| ErrorKind::InvalidKey)?
);
let mut signing_state = signature::RSASigningState::new(key_pair)
.map_err(|_| ErrorKind::InvalidKey)?;
let mut signature = vec![0; signing_state.key_pair().public_modulus_len()];
let rng = rand::SystemRandom::new();
signing_state.sign(ring_alg, &rng, signing_input.as_bytes(), &mut signature)
.map_err(|_| ErrorKind::InvalidKey)?;
Ok(
base64::encode_config::<[u8]>(&signature, base64::URL_SAFE_NO_PAD)
)
}
pub fn sign(signing_input: &str, key: &[u8], algorithm: Algorithm) -> Result<String> {
match algorithm {
Algorithm::HS256 => sign_hmac(&digest::SHA256, key, signing_input),
Algorithm::HS384 => sign_hmac(&digest::SHA384, key, signing_input),
Algorithm::HS512 => sign_hmac(&digest::SHA512, key, signing_input),
Algorithm::RS256 | Algorithm::RS384 | Algorithm::RS512 => sign_rsa(algorithm, key, signing_input),
}
}
fn verify_rsa(alg: &signature::RSAParameters, signature: &str, signing_input: &str, key: &[u8]) -> Result<bool> {
let signature_bytes = base64::decode_config(signature, base64::URL_SAFE_NO_PAD)?;
let public_key_der = untrusted::Input::from(key);
let message = untrusted::Input::from(signing_input.as_bytes());
let expected_signature = untrusted::Input::from(signature_bytes.as_slice());
let res = signature::verify(alg, public_key_der, message, expected_signature);
Ok(res.is_ok())
}
pub fn verify(signature: &str, signing_input: &str, key: &[u8], algorithm: Algorithm) -> Result<bool> {
match algorithm {
Algorithm::HS256 | Algorithm::HS384 | Algorithm::HS512 => {
let signed = sign(signing_input, key, algorithm)?;
Ok(verify_slices_are_equal(signature.as_ref(), signed.as_ref()).is_ok())
},
Algorithm::RS256 => verify_rsa(&signature::RSA_PKCS1_2048_8192_SHA256, signature, signing_input, key),
Algorithm::RS384 => verify_rsa(&signature::RSA_PKCS1_2048_8192_SHA384, signature, signing_input, key),
Algorithm::RS512 => verify_rsa(&signature::RSA_PKCS1_2048_8192_SHA512, signature, signing_input, key),
}
}
impl Default for Algorithm {
fn default() -> Self {
Algorithm::HS256
}
}