KittyTreats Lab

Verification and Privacy

Proof without publishing private notary files

Face to Face Notary can create a verification receipt for a completed remote online notary session. The receipt is designed to help confirm that a final notarized PDF matches the record created for that session, while keeping client documents and personal details private.

Request a Quote How the Check Works
Example OP_RETURN payload Face to Face|RON1|record:26|sha256:0ac475b98330cf1f988fe2a7bbcd393c74e9431070783594bfb6c156200ceece

Final PDF Fingerprint

The final notarized PDF is hashed with SHA-256. The hash acts like a fingerprint: changing even one byte in the PDF creates a different hash.

Private Files Stay Private

Client documents, names, emails, phone numbers, signatures, seals, recording links, and meeting links are not written into the public OP_RETURN payload.

Public Anchor

The public BSV record contains the Face to Face protocol label, an internal record id, and the SHA-256 hash used for later comparison.

How Verification Works

Similar to checking a downloaded file

If you have ever downloaded software and compared it to a published SHA256SUMS file, the idea is similar. Face to Face hashes the final notarized PDF and stores the hash in the session receipt. If a copy of the PDF is later uploaded to the verification page, the app hashes that uploaded file in memory and compares the result to the receipt hash.

A matching hash means the uploaded PDF matches the final PDF fingerprint recorded for that Face to Face session. A mismatch means the uploaded PDF is not byte-for-byte the same file.

The document stays private. Its fingerprint can be public.
  1. Private file

    Start with the final PDF

    The completed document is the source for the check. Its contents are kept off the blockchain.

  2. SHA-256

    Create a fingerprint

    The app calculates a 64-character hash from the file’s bytes and records it in the session receipt.

  3. Optional public record

    Anchor the fingerprint

    A BSV transaction can carry the hash and record label in an OP_RETURN data output. The receipt shows the anchor status.

  4. Later comparison

    Check a copy

    The verification page hashes the PDF you upload and compares it with the receipt. Matching hashes indicate matching file contents.

Same fingerprint → matching file. A different fingerprint means the file’s bytes differ, even if the pages look similar.

The file comparison and blockchain anchor status are separate checks. A matching hash does not by itself establish who signed a document or whether its contents are true.

Three different jobs

Hashing, encryption, and the blockchain

Each plays a different role in protecting a file and checking it later.

Compare

Hashing makes a fingerprint

SHA-256 produces a one-way digest. It cannot be decrypted into the PDF. Someone with a copy can calculate its hash and check for a match.

Protect

Encryption protects stored files

The app encrypts new files saved through its private notary file storage using Fernet. The server uses a secret key to read those files for authorized workflows. This happens off-chain.

Record

OP_RETURN carries public data

OP_RETURN is a place for data in a blockchain transaction. It does not encrypt that data. Here, the public payload contains a record label and hash, rather than the private PDF.

Public Payload

What appears on-chain

The readable Face to Face OP_RETURN payload follows this format: 

Face to Face|RON1|record:<record_id>|sha256:<final_pdf_sha256_hash>

RON1 means Remote Online Notary protocol version 1. The version label keeps this first format clear if a future version is added later.

Privacy note

A hash cannot be used to reconstruct the original PDF. It is a one-way fingerprint for comparison, not a copy of the document. The final PDF itself is not placed on-chain.

Private vs. Public

Private notary data is kept out of the public payload

Stays off-chain

Your private information

  • Client name, email, phone number, or address
  • Client document contents
  • Signature images or notary seal images
  • Google Meet links or recording links
  • Internal notes or journal details
Public anchor & receipt

The verification reference

  • Face to Face protocol name
  • RON protocol version
  • Internal notary record id
  • Final PDF SHA-256 hash
  • When anchored: a transaction ID identifies the public BSV transaction

Ready to Start?

Request an Ohio notary quote

Share the appointment details, document type, and whether you need mobile or remote online notary planning. Face to Face Notary will review the request and follow up.

Face to Face Notary Request a Quote rachael@kittytreats.org