Version: 1.0.0 (2026-08-31) · Core: capglyph-core 0.1.0 · Status: Stable draft
Canonical specification for the CapGlyph image-native credential and stego-payload protocol.
- Repository:
CapGlyph/capglyph-spec(this repo) — public, versioned - Core implementation:
CapGlyph/capglyph-core—capglyph_core::framing,keying,ecc,carrier,registration - Conformance vectors:
CapGlyph/capglyph-test-vectors— cross-language fixtures (valid/invalid/expired/revoked/malformed/tampered/images) - Harness:
capglyph conformance test --vectors <path>(inCapGlyph/capglyph-cli)
| Document | Path | Scope |
|---|---|---|
| Umbrella spec | spec.md |
version, canonical CBOR, hash/sig, image normalization, payload encoding, version negotiation, error semantics (normative index) |
| Protocol | docs/protocol.md |
issuance / verification / consumption flow, hybrid blind→original-assisted extractor |
| Credential Format | docs/credential-format.md |
CBOR credential, token_id, CBOR array framing, field table |
| Image Binding | docs/image-binding.md |
cover binding, geometry, carrier lattice (DCT/DWT), image normalization |
| Verification | docs/verification.md |
original-assisted R = I_aligned - I_orig, correlation, secret-layer differential pairs |
| Consumption | docs/consumption.md |
atomic UPDATE … RETURNING, idempotency, audit |
| Policy | docs/policy.md |
scope language, expiry, revocation, key rotation (kid), WebAuthn binding |
Detailed companions:
docs/canonical-serialization.md— deterministic CBOR rulesdocs/error-semantics.md— error codes & fail-closed behavior
Spec v1.0.0 corresponds to capglyph-core v0.1.0. Carrier v1 (HMAC-SHA256 framing, Repetition8/BCH ECC, DCT F[2,3]/F[3,4] and DWT Haar LH lattice) is stable. Ed25519/ML-DSA signatures and RS full correction are reserved for v1.1 / v2 (never stacked, negotiated via version/kid).
spec.md → protocol.md → credential-format.md → image-binding.md → verification.md → consumption.md → policy.md.
For security economics (carrier ≠ security bits, five attacks Guess/Forge/Extract/Detect/Steal) see the companion CapGlyph/capglyph-docs cryptographic-security.md (normative) and capacity-robustness-and-threats.md (measured FER).
capglyph conformance test --vectors ../capglyph-test-vectors/vectors
python3 ../capglyph-test-vectors/scripts/conformance.py --vectors ../capglyph-test-vectors/vectorsAll valid/ vectors must open and verify; all other categories must fail with the documented error code.
Apache-2.0 — same as CapGlyph/capglyph-core.