pseudonymize() used an unkeyed sha256 over 'salt:id' truncated to 64
bits, and the DSR deletion certificate hashed the raw subjectId with no
salt at all (audit finding A13). Both now use HMAC-SHA256 keyed by
AUDIT_PSEUDONYM_SALT, truncated to 128 bits. Rotation semantics are
documented on pseudonymize(): a key rotation changes future pseudonyms
only — stored rows keep old tokens and erasure still matches by real
actorId — and the certificate change likewise affects new certificates
only.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Adds `pseudonymize(actorId)` in core-audit — SHA-256 of salt+":"+actorId
truncated to 16 hex chars, prefixed "erased-". Salt from
AUDIT_PSEUDONYM_SALT env (fallback dev label). 6 unit tests: deterministic,
salt-change-differs, fallback-no-throw.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
