← HashDocket

Proof of existence for a document — without uploading the document

HashDocket creates a SHA-256 fingerprint of a file directly in your browser. The fingerprint can then be entered in a public registry after a verified Bitcoin payment. The original PDF, image, contract, archive or source file stays on your device.

Create a proof

What a document fingerprint proves

A SHA-256 fingerprint is a one-way digest derived from the exact bytes of a file. If even one byte changes, the fingerprint changes. A later copy can therefore be hashed again and compared with the registered value.

Privacy by design

HashDocket does not need the original document to create the fingerprint. Hashing happens locally in the browser, so confidential material can remain private.

How HashDocket works

1. Select a file in your browser.
2. The browser calculates its SHA-256 fingerprint locally.
3. Pay the one-time registration fee in Bitcoin.
4. After the Bitcoin transaction receives its first confirmation, the fingerprint is published in the HashDocket registry.
5. Anyone can later recompute the SHA-256 hash and verify whether that exact file matches the recorded proof.

Typical uses

Examples include contracts, manuscripts, source-code releases, research drafts, photographs, design files and other digital material where you want an independently checkable record associated with a specific file version.

Start

No account or subscription is required.

Open HashDocket