- warden/mask.py: fingerprint()/mask_value() — presence, length, 8-char sha256
prefix; never the value.
- proxy.proxy_fetch_fingerprint + `warden access --fingerprint`: masked status view
(presence/length/hash) that emits no value, so it bypasses the T02 stdout guard.
Lets two parties compare sha256 prefixes to confirm a shared value without seeing
it (e.g. rotation landed).
- documented as defense-in-depth (raw bao bypasses it) in OperatorAccessAssist.md
and the module docstring.
- tests: tests/test_mask.py + CLI fingerprint test. 299 pass.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
