feat(crypto,pki): implement Wave 1 — hybrid KEM + PKI

aura-crypto: X25519 + ML-KEM-768 (FIPS 203) hybrid KEM, HKDF-SHA256 session key derivation, ChaCha20-Poly1305 AeadSession with counter nonces; genuine NIST ACVP ML-KEM-768 KAT (decapsulation vector). 16 tests green, clippy clean. aura-pki: self-signed CA, server/client cert issuance (rcgen 0.14), mutual X.509 chain verification via rustls-webpki, CRL revocation. 8 tests green. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-25 17:55:06 +03:00
parent f78633e04f
commit b8ce58ddf0
18 changed files with 1712 additions and 5 deletions
@@ -1 +1,53 @@
-//! aura-pki — PKI: CA, certificate issuance and verification (skeleton; implemented in Wave 1).
+//! aura-pki — mutual X.509 authentication for the Aura VPN.
+//!
+//! A self-signed Aura CA ([`AuraCa`]) issues a server certificate (carrying a
+//! DNS SAN) and per-client certificates (`CN = client_id`). The server verifies
+//! client certificates against the CA and the client verifies the server
+//! certificate against the CA via [`AuraCertVerifier`]. v1 revocation is a
+//! simple CRL: a set of revoked certificate serials or client ids, see
+//! [`AuraCertVerifier::set_revoked`] and [`CrlStore`].
+//!
+//! Certificates use ECDSA P-256 / SHA-256 keys (rcgen's default), and chain
+//! verification is performed with `rustls-webpki` against the CA trust anchor.
+
+mod ca;
+mod cert;
+mod store;
+
+pub use ca::{AuraCa, IssuedCert};
+pub use cert::AuraCertVerifier;
+pub use store::CrlStore;
+
+/// Errors produced by the Aura PKI.
+#[derive(Debug, thiserror::Error)]
+pub enum PkiError {
+    /// A PEM/DER blob could not be parsed into a certificate.
+    #[error("failed to parse certificate: {0}")]
+    CertParse(String),
+
+    /// The supplied certificate chain was empty.
+    #[error("empty certificate chain")]
+    EmptyChain,
+
+    /// The trust anchor (CA certificate) could not be constructed.
+    #[error("invalid trust anchor: {0}")]
+    TrustAnchor(String),
+
+    /// Chain verification against the CA failed (bad signature, expired,
+    /// untrusted issuer, wrong key usage, ...).
+    #[error("certificate chain verification failed: {0}")]
+    Verification(String),
+
+    /// The server certificate is not valid for the requested name.
+    #[error("certificate is not valid for name '{0}'")]
+    NameMismatch(String),
+
+    /// The end-entity certificate did not contain the expected identity, e.g. a
+    /// client certificate without a Common Name.
+    #[error("missing identity in certificate: {0}")]
+    MissingIdentity(String),
+
+    /// The certificate was found in the revocation list.
+    #[error("certificate is revoked: {0}")]
+    Revoked(String),
+}