Nothing revealed
Only the fingerprint
The document never leaves your device — just its hash, which reveals nothing about the contents.
🖋️
Notary
Prove it existed — without showing it.
Timestamp that a document existed at a moment in time, without revealing the document. Only its fingerprint leaves your device — carried over the private lane, countersigned post-quantum.
proof-of-existence
nothing revealed
post-quantum countersign
live
A timestamp that gives nothing away
To prove a file existed by a certain time, NULL hashes it on your device and sends only the SHA-256 fingerprint over the private lane. It comes back with a post-quantum issuer countersignature (ML-DSA-65) and, if you want, your own endorsement. Honest scope: it proves existence-by-then and your endorsement — not authorship or uniqueness.
Post-quantum
Countersigned to last
An ML-DSA-65 issuer countersignature makes the timestamp provable against a future quantum adversary.
Honest scope
Existence, not authorship
It proves the document existed by that time and your endorsement — not who wrote it or that it’s unique.
How it works
Hash it locally
Your device computes the document’s SHA-256 fingerprint — the file itself stays with you.
Get it countersigned
The fingerprint goes over the private lane and returns with a post-quantum issuer countersignature and a timestamp.
Prove it later
Anyone can re-hash the document and verify the signed proof that it existed by that moment.
🖋️
Timestamp, in confidence
Proof that stands up later — without ever exposing what you’re proving.
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