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How Document Verification Certificates Work

Understand how Ed25519 signatures and SHA-256 hashes prove your documents are authentic and unmodified.

Last updated: 15 January 2025

The Verification Process

Every RedactProof export includes a verification certificate (verification.json) that allows anyone to independently confirm the document's authenticity.

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Three Ways to Verify

1. Self-Contained Verification

The PDF itself contains a certificate page with a QR code. Recipients can scan this code to verify the document without needing the separate verification.json file.

2. Online Verification

Visit redactproof.com/verify and upload the verification.json file and the redacted PDF. The system will:

  1. Verify the Ed25519 signature on the certificate
  2. Calculate the SHA-256 hash of your PDF
  3. Compare the hash to the one in the certificate
  4. Confirm whether the document is authentic and unmodified

3. Certificate ID Lookup

Each certificate has a unique ID (e.g., "rp_abc123xyz"). Enter this ID at the verification page to look up the certificate details without uploading files.

What the Signature Protects

The Ed25519 digital signature covers ALL fields in the certificate. This means any attempt to modify the certificate - even changing a single character - will cause verification to fail.

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What Verification Proves

What It DOES Prove

  • Document was processed by RedactProof at the stated time
  • Document has not been modified since export
  • Redacted document was derived from a specific original

What It Does NOT Prove

  • That redactions are legally sufficient or accurate
  • The identity of the person who performed the redaction
  • Regulatory compliance or legal admissibility

Professional Responsibility

Verification certificates provide cryptographic evidence of document handling, but they do not replace professional judgement. Always consult with your legal team regarding compliance requirements for your specific use case.

Certificate Validity

Verification certificates are valid indefinitely. The verification.json file contains all cryptographic data needed for verification, with no expiry date. You can verify a document years after it was redacted using the same certificate.

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