zerodds-security-keyexchange

Ephemeral Diffie-Hellman key agreement for the DDS-Security authentication handshake per OMG DDS-Security 1.1 §8.3.2. Wrapper around ring::agreement + ring::hkdf. Safety classification: SAFE.

Spec mapping

What's inside

• KeyExchange + Suite::X25519 / Suite::P256Ecdh — ephemeral-DH roundtrip with derive_shared_secret() → 32-byte HKDF-SHA256 output.

Layer position

Layer 4. Consumed by zerodds-security-pki in the authentication-handshake state machine.

Quickstart

use zerodds_security_keyexchange::KeyExchange;

let alice = KeyExchange::new().expect("alice");
let bob = KeyExchange::new().expect("bob");

let a_pub = alice.public_key().to_vec();
let b_pub = bob.public_key().to_vec();

let s1 = alice.derive_shared_secret(&b_pub).expect("alice derive");
let s2 = bob.derive_shared_secret(&a_pub).expect("bob derive");
assert_eq!(s1, s2);

Suite coverage

Non-goals

RSA-OAEP key transport (spec §8.3.2.11 alternative form) is not in RC1 — all relevant vendors (Cyclone DDS, FastDDS, RTI Connext) speak ECDH/X25519.

Stability

1.0.0-rc.1. Public API + wire format (public-key encoding) RC1-stable.

Tests

cargo test -p zerodds-security-keyexchange

11 unit tests + 1 doc test green.

License

Apache-2.0.

See also

• docs/spec-coverage/dds-security-1.2.md.
• zerodds-security-pki.
• zerodds-security-crypto.