1Bridge Vault

Verify 1Bridge Signature

Open or paste a verify link from a signed contract or watermarked document to load its attestation, then upload the file. 1Bridge verifies the invisible watermark, recomputes SHA-256, and confirms it matches the Bitcoin-anchored hash—proving authenticity and when the document was finalized.

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How 1Bridge verifies a document

Verification combines four independent checks. Each layer answers a different question; together they confirm authenticity, integrity, and when the document was finalized.

  1. Signed attestation

    A verify link (?sig=…) loads a record from 1Bridge Vault: the signing request, who signed, and when. The “Signed contract attestation” card shows that metadata before you upload anything.

  2. Document fingerprint (SHA-256)

    Every file has a unique SHA-256 hash of its exact bytes. Change a single character and the hash changes. When you upload the PDF, we recompute the hash and compare it to the one stored with the attestation.

  3. Bitcoin anchoring

    That fingerprint is timestamped on the Bitcoin blockchain (status stamped → confirmed at a block). A match proves the document existed in this form at that time and has not been altered since.

  4. Invisible watermark

    An invisible carrier payload is embedded in the file and tied to the attestation. Detection confirms the file came from 1Bridge even if it was re-exported or screenshotted—complementing the hash check.