Independently reproducible cryptographic verification.
H33 verifiers are deterministic. Any conformant implementation processing the same proof produces identical challenge derivation, identical transcript state, identical replay outputs, and identical rejection behavior — without contacting H33 infrastructure, without trusting a single vendor, without ambiguity.
Most security evidence cannot be re-verified after the fact. Logs are mutable. Screenshots are unsigned. Vendor dashboards are vendor-controlled. Six months later, none of it answers "what actually happened."
The verifier either reproduces the same trust state — or it fails deterministically.
The transcript is the source of truth. Every commitment — trace, constraint, FRI layer, AIR identifier — is absorbed into the SHA3-256 sponge before the dependent challenge is derived. No gaps. No mutable state injection between commit and challenge.
Every verifier challenge is derived deterministically from the transcript state. The OtterSec Fiat-Shamir vulnerability pattern that impacted six independent zkVM implementations in March 2026 does not apply — H33's transcript follows strict absorb-then-squeeze discipline.
The FRI verifier independently regenerates query positions from the Fiat-Shamir transcript. Prover-supplied positions are matched against derived positions. Any mismatch causes immediate rejection.
Each proof type and protocol step uses a unique prefix. Length-prefixed and labeled hash inputs prevent concatenation collisions and cross-context replay. Native length-extension resistance.
When a proof fails to verify, every conformant verifier returns the same structured rejection code from the HATS_ERR_* namespace. Operators, auditors, and downstream systems get one canonical reason — not one opaque "verification failed."
The H33 reference verifier emits deterministic conformance vectors covering positive cases, negative cases, and adversarial corpora. Independent implementations prove compatibility by reproducing identical roots, hashes, replay outputs, and rejection codes against the same vectors.
Positive vectors — prove valid governance satisfaction and correct acceptance behavior.
Negative vectors — prove deterministic rejection. Without negative vectors, conformance certification is incomplete. Compliance tooling, verifier qualification programs, and adversarial validation all depend on proving correct rejection behavior, not just correct acceptance.
Malformed-proof corpus — 29-test adversarial fuzz corpus over the STARK protocol surface.
A third-party implementation in any programming language is conformant when it produces identical root hashes, replay frame hashes, Merkle roots, validity determinations, and structured rejection codes against the same conformance vectors — without ever calling H33 infrastructure.
Proof
↓
Verifier A ─┐
Verifier B ─┼── IDENTICAL RESULT
Verifier C ─┘
Deterministic replay across independent implementations.
No implementation-defined behavior. No verifier ambiguity. No trusted verifier dependency.
Every proof verification returns a deterministic replay integrity classification. Third parties can distinguish complete, partial, and tampered evidence without contacting H33 and without trusting any single verifier.
FULLY_REPLAYABLE
Cryptographically complete evidence. Every commitment, challenge, and rejection path reproduces under any conformant verifier.
STRUCTURALLY_VALID
Partially reconstructable evidence. Proof structure passes but one or more replay frames are unavailable (e.g., expired external anchor).
INVALID
Invalid or tampered proofs. Deterministic rejection from the HATS_ERR_* namespace identifies the exact failure mode.
Conformance is proved against an adversarial corpus, not a happy path. Every malformed-proof case produces a deterministic rejection code and replay classification. CI breaks on any drift.
| Property | Value |
|---|---|
| Canonical transcript vectors | Frozen |
| Deterministic verifier mode | Yes |
| Structured rejection codes | HATS_ERR_* |
| Replay integrity grading | FULLY_REPLAYABLE / STRUCTURALLY_VALID / INVALID |
| Adversarial malformed-proof corpus | 29 tests |
| Total STARK protocol tests | 238 |
| Conformance vector format | Verifier-generated |
| Negative vectors | Required for conformance |
Determinism is what makes evidence survive vendor transitions, organizational changes, infrastructure replacement, and decade-scale archival. The verifier never depends on H33 being online — or even existing.
Conformance vectors, transcript freeze vectors, the HATS_ERR_* namespace, and the malformed-proof corpus are part of the H33 reference verifier distribution.