The crypto foundation for group-owned secrets (the §5.3 'single hardest
correctness detail'), done first and proven before the storage/resolution
layer.
- SecretOwner{App(AppId)|Group(GroupId)}; secret_aad/seal/open take the
owner. The app AAD is byte-identical to the pre-Phase-3
'secret:{app_id}:{name}', so every existing v1 row decrypts unchanged;
group secrets use a disjoint 'secret:group:{group_id}:{name}' namespace
(the 'group:' infix separates app/group AAD even for equal UUIDs).
- All callers (SDK get/set, secrets_api, apply email-secret read) wrapped
in SecretOwner::App — behavior identical for app secrets.
- New audit test aad_distinguishes_app_and_group_owner proves the two
namespaces don't collide (both directions, even reusing the UUID); the
existing cross-app/cross-name swap audit tests stay green.
16 secrets_service tests pass; clippy clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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