Function encrypt_log_record 

pub fn encrypt_log_record(
    key: &SecretKey,
    epoch: u32,
    lineage: &[u8],
    log_version: u64,
    t: u64,
    plaintext: &[u8],
) -> Result<Vec<u8>, CryptError>

Encrypts one transaction-log record payload.

The AAD binds the database lineage, the log’s lease version, the transaction number, and the key epoch, so a record can neither be replayed at another basis nor moved between the per-lease-version log files that takeover fencing relies on.

Unlike blobs, log records are not content addressed and nothing requires re-encoding a record to the same bytes, so this uses one-pass AES-256-GCM with a fresh random nonce rather than a nonce derived from (log_version, t). A derived nonce would be reused whenever a transaction number is re-issued with different content — which happens whenever an append is torn by a crash before it is acknowledged, and truncated away on recovery. Key/nonce reuse is fatal under GCM; storing 12 bytes is not.

Errors

Returns a CryptError when randomness is unavailable or encryption fails.