Trust Spine · /keys

Trust roots & signing keys

Every signed Project-AI artifact resolves to one of these published keys. Use them to verify receipts offline; do not trust receipts whose signer id does not appear here.

Active signing keys

Key id	Role	Alg	Fingerprint	Issued	Expires	Status
pai-audit-2026-q2	Audit ledger — receipt signing	Ed25519	SHA256:7e3b91d6c2a0… (published with release)	2026-04-01	2026-09-30	ACTIVE
pai-warrant-2026	Governance warrant signing	Ed25519	SHA256:ab18ff04e6d1… (published with release)	2026-01-15	2026-12-31	ACTIVE

TSA roots (RFC 3161 timestamping)

DigiCert TSA

PINNED

RFC 3161 timestamping

DigiCert Assured ID Timestamping CA

Offline verification — canonical sequence

The same four-step sequence is reproduced on /verify, /reproduce, /evidence, and /faq. Run them in order against a downloaded receipt + signature + TSR.

Ed25519 signature

# 1. Verify Ed25519 signature over the receipt JSON
openssl pkeyutl \
  -verify \
  -pubin -inkey pai-audit-2026-q2.pub \
  -rawin -in receipt.json \
  -sigfile receipt.sig

RFC 3161 timestamp

# 2. Verify RFC 3161 timestamp from the TSA
openssl ts -verify \
  -in receipt.tsr \
  -data receipt.json \
  -CAfile digicert-tsa-roots.pem

Receipt hash

# 3. Recompute the receipt hash and compare to the receipt body
sha256sum receipt.json
# expected = receipt_hash field inside receipt.json

Chain continuity

# 4. Walk the chain: every receipt's prev_hash must equal the
#    receipt_hash of the previous entry (chain_seq - 1).
jq -r '[.chain_seq, .prev_hash, .receipt_hash] | @tsv' chain/*.json \
  | sort -n | awk 'NR>1 && $2 != prev { print "BREAK at seq", $1; exit 1 } { prev = $3 }'

Key material is distributed with each release artifact on Zenodo and GitHub. Compare the fingerprint above to the file you downloaded before trusting it. Public key files: pai-audit-2026-q2.pub, pai-warrant-2026.pub — bundled with each release; SHA-256 checksums published alongside.

Rotation log

2026-04-01
Audit signing key rotated: pai-audit-2025-q4 → pai-audit-2026-q2.
2026-01-15
Warrant signing key established for 2026 cycle.
2025-10-02
Genesis audit signing key archived; chain continuity preserved.