Validator

Just upload a Verifiable PDF to the online validator and check if the document is the original or was tampered with in seconds. The validator is open source so anyone can host one. Moreover, any one is capable of verifying all VPDFs irrespective of who issued them.

You can test right now using the three sample VPDFs provided,
by downloading and drag’n’drop them to the dropzone above.

Valid PDF

Revoked PDF

Expired PDF

Design Principles

Decentralized

PDF documents can be verified on any validator by consulting the Bitcoin blockchain. Issuers can host a validator on their website, if they wish.

Unforgeable

Any kind tampering of the PDF will immediately invalidate it as it will change the digital fingerprint that was anchored in the blockchain.

Simplicity

Straight-forward process using the most-widely used medium of exchange for documents. PDFs are already the de facto document format.

Open

Following Bitcoin’s example we wanted our solution to be open and permissionless. The core library, which includes all the functionality, is open source and anyone can use it to issue, revoke and validate credentials.

How it works

Issuing PDFs

Calculate the digital fingerprint of one or more PDFs using a Merkle tree.
The fingerprint is anchored into the blockchain by including it in a transaction.
The transaction ID and the respective Merkle proof is added into the PDF metadata. This new PDF (vPDF) is now provably tamperproof.

Revoke a vPDF

Calculate the fingerprint of the original PDF.
Anchor this fingerprint into the blockchain by including it in a transaction marking it as a revocation
From now on this vPDF will be considered revoked (invalid). This can apply to multiple PDFs at once.

Validate a vPDF

Extract the proof and calculate the fingerpint of the PDF.
Check that the fingerprint is in the blockchain by using the proof.
Replies if the given vPDF is Valid, Revoked or Expired, according to the blockchain, as well as identification proof for the issuer.