This website requires JavaScript. The certification service calculates the cryptographic digest of your document client-side. Alternatively, you can calculate and submit your document data using shasum and curl. See the Developer API for more information, read our about page, get the news, or contact us.

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Proof of Existence
Written forever.

Instant & secure Proof of Existence for any Document

Select a document and have it certified in the Bitcoin blockchain
If it has been certified already, you will be redirected to the original record.
Learn more.

Drag and drop your document here, or choose a file. The file will not be uploaded.

Ongoing Submissions

Documents already registered for certification, waiting for payments.

Certifications

Documents of proven existence, confirmed in the blockchain