ouroboros/src/lib/crypt/keyrot.c, branch master

lib: Separate rekey replay from epoch conflict

2026-07-08T09:02:24+00:00

keyrot_rekey() treated any re-key attempt against a live epoch (current or previous) the same way, whether the offered root key matched the live one (a replay) or was genuinely different (a conflict). Compare the offered key against the live batch's root and return -EREPLAY for a match, keeping -1/-ECRYPT for an actual conflict, so callers can handle replayed re-keys distinctly from real ones. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Reject re-key to a live epoch

2026-07-08T09:02:23+00:00

A re-key epoch arrives from the peer, so we need to reject duplicates to avoid two batches sharing a wire epoch with different keys. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders

lib: Harden symmetric-key rotation

2026-06-29T06:32:58+00:00

Flow crypto signalled rotation with a single phase-parity bit, so a loss burst that hid an even number of rotations went unnoticed and wedged the flow for good. Each packet now carries a small cleartext selector naming its key directly, so a receiver that falls behind recovers on the next packet instead of getting stuck. The selector also serves as the AEAD nonce and is authenticated as associated data (AAD). Key rotation moves into a new backend-agnostic keyrot module that rotates sub-keys to bound AEAD usage while preserving forward secrecy. Signed-off-by: Dimitri Staessens Signed-off-by: Sander Vrijders