Zero data collected. No tracking, no logs of what you seal. Everything runs in your browser.
VerifyBundle
Cryptographic records · verifiable by anyone, offline

Create records
anyone can verify.

Turn a file or a note into a small, self-contained record. Anyone can confirm it has not changed since you sealed it: offline, on any device, with no account and no trust in us.

Create a recordVerify one

No server · no account · no expiry

  1. Datayour file or note
  2. SHA-256accb14f388…9a4998
  3. Merkle rootf6fa2cd005…b1980e
  4. Signaturesigned in your browser
  5. Checkpointsigned · verifiable offline
How it works

A record you can hold, and check yourself.

A record is a small, self-contained bundle. It proves the data inside is exactly what you sealed and has not changed since. The proof is pure math, so it does not depend on us being online, in business, or trusted.

  1. 01

    Seal

    A fresh key signs your data in your browser, then is discarded. Your file and your key never leave the page.

  2. 02

    Hold

    You download one portable record; it carries its own proof inside. The record is yours. You keep it. You control it.

  3. 03

    Verify

    Anyone checks it with the open offline verifier. No network, no company, no expiry.

The boundary

What a record proves. And what it never claims.

Honesty is the product. We are precise about the line a record does not cross.

It proves the data has not changed since the moment you sealed it. It does not prove the data was true or authentic.
Proves
  • The data is unchanged since you sealed it.
  • It matches the record, exactly.
  • The time committed at sealing (not a certified time authority).
  • It was sealed by the holder of a signing key.
Never claims
  • That the data is true.
  • Who the sealer is (the key is anonymous here).
  • Physical presence, or that a real-world event happened.
  • That nothing was left out.
  • That it is legal evidence, notarized, or admissible in court.
Under the hood

Post-quantum, and open.

Records are sealed with a hybrid signature: ML-DSA-65, a post-quantum scheme standardized by NIST in FIPS 204, paired with Ed25519. An attacker would have to break both, so the proof stays sound as long as either does, including against future quantum computers. The construction is open: anyone can re-implement the verifier from the published specification and conformance vectors.

ML-DSA-65 · Ed25519 · SHA-256 · Merkle · signed checkpoint

Create a record now.

It takes a few seconds, costs nothing, and the proof outlives us.

Create a record