Related · tier-1 reading. For what a portable artifact actually is, see Portable Artifact.
Documents signed today must be legally valid in 2055. RSA won't survive that long. Neither will the CA that issued your signing certificate. ArchiveSign solves both problems — post-quantum signatures with embedded timestamps, certificate chains, and revocation snapshots that survive infrastructure decay.
Every capability is designed for documents that must remain legally verifiable for decades — long after the signing CA has disappeared and the original algorithms have been deprecated.
RSA and ECDSA signatures have a shelf life. Key lengths that are secure today will be breakable within 10–15 years. Single-algorithm signatures create a single point of failure: one cryptanalytic breakthrough invalidates every document you have ever signed.
Dual-sign every document with SLH-DSA (hash-based, stateless, NIST FIPS 205) and ML-DSA (lattice-based, FIPS 204). SHA3-256 + BLAKE3 dual hashing. If one algorithm family falls, the other holds. Batch mode: 500 documents per signing request.
NIST selected both SLH-DSA and ML-DSA because they rely on fundamentally different mathematical hardness assumptions. A lattice breakthrough does not affect hash-based signatures, and vice versa. Every ArchiveSign document now includes an H33 Substrate commitment — a 74-byte post-quantum attestation binding three independent cryptographic families (Dilithium, FALCON, SPHINCS+) to the document hash. The commitment anchors the signature to a verifiable chain of trust that survives any single-family cryptanalytic breakthrough.
A signature proves who signed. It does not prove when. Without a trusted timestamp, an adversary who compromises a key can backdate forgeries. Commercial TSAs use RSA — their timestamps will be forgeable once quantum arrives. Most TSAs make no long-term storage commitment.
H33 operates its own RFC 3161-compliant Timestamp Authority. Every timestamp token is signed with Dilithium (ML-DSA). Tokens are stored indefinitely with a contractual 50-year availability commitment. The TSA itself is post-quantum from day one.
A timestamp is the anchor that makes long-term signatures possible. Without it, key compromise at any point in the future retroactively invalidates every signature. A Dilithium-signed timestamp is the only kind that survives a quantum adversary.
CAs disappear. OCSP responders go offline. CRL distribution points return 404. Within 10 years of signing, the infrastructure needed to validate a certificate chain often no longer exists. Your signature is technically valid but practically unverifiable.
ArchiveSign embeds the full certificate chain, OCSP responses, and CRL snapshots directly into the signature envelope at signing time. A key transparency log (append-only Merkle tree) records every certificate issuance. Verification requires zero external lookups.
ETSI long-term signature formats (PAdES-LTA, CAdES-A) require this. The entire validation context must travel with the document. If a verifier needs to contact an external server, the signature is not truly archival.
Standard signature verification checks one thing: does the math work? It does not check whether the timestamp is still trustworthy, whether the certificate chain is complete, whether the signing algorithm has been deprecated, or whether the signature will still be valid in 5 years.
Seven verification stages: (1) hash integrity, (2) timestamp validation, (3) certificate chain completeness, (4) revocation status, (5) algorithm health assessment, (6) projected validity window, and (7) temporal consistency across all embedded proofs. Returns a structured report, not just pass/fail.
A signature that passes hash verification but uses a deprecated algorithm is a ticking time bomb. The 7-stage verifier catches signatures that are technically valid today but will fail within a predictable window — giving you time to re-sign before it is too late.
Algorithms age. SHA-1 was deprecated. RSA-1024 is broken. Every archival signature will eventually need maintenance: new timestamps with stronger algorithms, algorithm upgrades, health assessments across millions of stored documents. Nobody does this today.
Automated re-timestamping when algorithm strength thresholds are crossed. Algorithm upgrade path that preserves the original signature chain while adding new layers. Bulk health assessment: scan 10,000 documents in a single API call and get a structured report of which signatures need attention.
A 50-year signature is not "set and forget." It requires active stewardship. The re-timestamping chain is what converts a 5-year algorithm into a 50-year signature. Without it, every archival promise is empty.
If the signing key is lost, stolen, or destroyed, every document signed with it becomes suspect. Single-custodian key storage is a single point of failure. Key escrow with a single third party just moves the risk.
Threshold cryptography splits signing keys across 2–5 independent agents. No single agent can sign or reconstruct the key alone. A key transparency log (append-only Merkle tree) records every key operation — issuance, rotation, escrow deposit, recovery — creating an immutable audit trail.
A signing key that lasts 50 years will outlive employees, departments, and possibly the organization that created it. Threshold cryptography ensures the key survives personnel changes, corporate restructuring, and custody disputes without ever existing in a single location.
ArchiveSign is the long-term archive-signing expression of H33-74 — it produces and anchors a portable, durable signature artifact that stays independently re-verifiable offline for decades. Every signed document carries an embedded H33 Substrate commitment: a 74-byte post-quantum attestation binding independent cryptographic families to the document hash, so the record can be re-checked without the signing infrastructure still existing.
A signature made today must be verifiable in 2055 — long after the issuing CA, its revocation servers, and the original algorithms are gone. ArchiveSign makes the proof belong to the document, not the operator: the validation context travels inside the envelope and the receipt survives infrastructure decay and the post-quantum transition.
ArchiveSign produces and anchors the evidence; it does not render the verdict on it — an independent judgment over a signature is Verification's role. It does not monitor live systems (that is HATS), and it does not govern an AI agent's authority in the moment (that is Agent-008). Signature families (SLH-DSA, ML-DSA), hashes (SHA3-256, BLAKE3), and timestamp/format standards (RFC 3161, ETSI PAdES/CAdES/XAdES/JAdES) are external standards H33 uses and conforms to — never invented or owned.
Use it when a signed document must remain portable, offline-verifiable, and replayable for years after the systems that created it are gone — legal instruments, government records, long-dated financial and medical documents. Skip it for short-lived signatures with no long-term evidentiary value, for live authorization decisions (Agent-008), or for continuous control monitoring (HATS) — the archival envelope adds durability those cases do not need.
Six capabilities, one cryptographic stack. Every component is shared across every supported format.
| Capability | H33 Component | Standard |
|---|---|---|
| Post-quantum signing | SLH-DSA + ML-DSA dual | FIPS 205 / 204 |
| Hash integrity | SHA3-256 + BLAKE3 dual | NIST / IETF |
| Timestamps | RFC 3161 TSA (Dilithium-signed) | RFC 3161 |
| Certificate chain | Full chain + OCSP + CRL embed | X.509 / RFC 6960 |
| Key management | Threshold escrow (2-of-5) | Shamir / Merkle log |
| Verification | 7-stage structured verifier | ETSI EN 319 102 |
| PDF signatures | PAdES-LTA envelope | ETSI EN 319 142 |
| XML signatures | XAdES-A envelope | ETSI EN 319 132 |
| CMS signatures | CAdES-A envelope | ETSI EN 319 122 |
| JSON signatures | JAdES envelope | ETSI TS 119 182 |
| Batch signing | 500 docs per request | <3s per signature |
| Maintenance | Re-timestamp + algo upgrade | 10K docs per scan |
Not a research prototype. Direct conformance with the frameworks that govern archival signatures in regulated industries.
All H33 products are included in our standard pricing tiers.
View Pricing →Boundaries and independence of the archival signature artifact.
RSA-2048 is projected to be breakable by quantum computers within 10–15 years. Even without quantum, CA certificates expire, revocation infrastructure disappears, and signing algorithms get deprecated. ArchiveSign dual-signs with SLH-DSA (hash-based) and ML-DSA (lattice-based), embeds timestamps and certificate chains, and anchors an H33-74 receipt so the evidence survives infrastructure decay.
ArchiveSign produces and anchors the durable evidence and reports its structured verification stages; the independent verdict over that evidence is rendered by Verification. ArchiveSign does not monitor live systems (HATS) or govern an agent's authority in the moment (Agent-008). It carries the proof; those adjacent systems decide, observe, and govern.
The full validation context — certificate chain, OCSP and CRL snapshots, timestamp tokens, and the H33-74 commitment — travels inside the envelope, so a verifier re-checks it offline against schema and content hash with zero external lookups, trusting no operator and no live service. Re-timestamping keeps the receipt replayable as algorithms age.
No. SLH-DSA and ML-DSA, the SHA3/BLAKE3 hashes, RFC 3161 timestamping, and the ETSI PAdES/CAdES/XAdES/JAdES envelopes are external NIST, IETF, and ETSI standards H33 uses and conforms to — never invented or owned. What H33-74 owns is the portable receipt and the discipline that keeps it re-verifiable over decades.
Sign a document with dual post-quantum algorithms. Watch the timestamp embed. Watch the certificate chain snapshot. Verify it with the 7-stage verifier. Every step is auditable. Every signature is built to outlast the infrastructure that created it.