Your digital records
will be challenged.
What's your evidence?
Independent cryptographic proof of what happened, when it happened, who issued it, and whether it has changed.
For systems where records must withstand scrutiny.
Turn AI activity into durable cryptographic evidence — hashes of full inputs, outputs, and tool context, with sequence integrity and independent time anchors before anyone disputes the record. Bodies stay with you; Sigill keeps only the hash and the chain.
Add externally verifiable evidence to approvals, submissions, exports, and customer-facing records without building trust-service infrastructure yourself.
Timestamp build artefacts, SBOMs, manifests, and release bundles. Systems further down the chain can reject files without verified evidence — and you can prove the artefact in production is exactly what the build produced.
Proof of when. Proof of who.
Sigill.ai is not the trust anchor — the independent authorities we connect you to are. We route your systems to external TSAs for proof of time, and apply advanced electronic seals (AdES) with your organisation's own certificate for proof of organisational origin. One integration for you; standard evidence that anyone can verify without us.
Proof of when
Cryptographically binds a file's SHA-512 hash to a specific moment in time, signed by a trusted Timestamp Authority. Produces a standard .tsr token verifiable with OpenSSL — independent of any platform, including ours.
- Signed by an external TSA — not self-claimed
- Hash computed locally — file never leaves your device
- Verifiable with
openssl ts -verify - Multiple TSAs available; automatic failover
Proof of who
Signs a document with your organisation's own X.509 certificate — bring your own certificate (BYOC). Recipients verify origin and integrity directly — no account, no portal, no Sigill.ai required.
- Your organisation's certificate — BYOC, no Sigill-issued keys
- PAdES for PDFs, CAdES for any other file type
- Both formats are ETSI standards used in eIDAS-compatible validation
- Verifiable in Adobe Acrobat, OpenSSL, and standard validators
- Can carry a qualified RFC 3161 timestamp where entitled — qualified electronic seals (QES) are on the 2026 roadmap
Proof only works if it exists before it's questioned.
Compliance audits
Auditors ask when data was created, processed, or approved — and who authorised it. Timestamps answer the when; advanced seals answer the who. Both operate independently of your own systems.
Prove what your model said, and when
Hash and timestamp the full input the model saw and the output it produced. Months later, prove what was asked, what context the model had, and what it answered — to a regulator, an auditor, or a counterparty disputing the record.
Working pattern: timestamped Claude agent →Software supply chain
Stamp every build artefact at CI time. A year later you can prove the artefact in production is exactly what the build produced — without trusting your own logs.
GitHub Actions: stamp every release →Evidence infrastructure via API.
RFC 3161 timestamps (standard and qualified, where entitled) and PAdES/CAdES advanced electronic seals, accessible programmatically. Open standards. For platforms that produce evidence automatically — no manual handling required.
One POST. Standard output. OpenSSL, PAdES and CAdES compatible.
One endpoint for timestamps, one for seals. Both produce open-standard outputs — .tsr tokens, PAdES PDFs, and CAdES detached signatures — verifiable with commodity tooling, no proprietary formats, no lock-in. Works with your CI pipeline, your agent, your platform.
HASH=$(sha256sum document.pdf | awk '{print $1}')
curl -X POST https://api.sigill.ai/tsa/stamp-hash \
-H "Authorization: Bearer <key>" \
-d "{\"tsaSlug\":\"auto\",\"hashHex\":\"$HASH\",\"label\":\"doc-2026-001\"}"curl -X POST https://api.sigill.ai/seal \
-H "Authorization: Bearer <key>" \
-d '{"documentBase64":"<b64_pdf>"}'openssl ts -verify \ -in output.tsr \ -data model-output.json \ -CAfile tsa-ca-bundle.pem # Verification: OK
Technical intro,
or a platform partnership?
We're a small team in Trondheim building independent proof infrastructure. Whether you're evaluating Sigill.ai for a platform or want a technical walkthrough — reach out.