PS
ProofSeal

About ProofSeal

Permanent, verifiable proof for text or files — anchored on Bitcoin

Our Philosophy

ProofSeal is built on a simple idea: important digital records deserve a permanent, independent timestamp. We use the Bitcoin blockchain as a neutral, decentralized foundation so your proof can be verified by anyone — now or in the future.

We focus on clarity and control: plain-language certificates, independent verification, and a workflow that respects privacy by default.

Neutral & Independent

We don’t gatekeep use‑cases. We provide the tools; you decide how to use them.

Our proof format is open, documented, and designed for independent verification. You never need to trust ProofSeal to verify a ProofSeal certificate.

Use Cases

Legal & Compliance

  • • Document & evidence timestamping
  • • Contract verification
  • • Regulatory compliance
  • • Intellectual property protection

Academic & Research

  • • Research publication
  • • Patent applications
  • • Academic credentials
  • • Data integrity

Business & Enterprise

  • • Audit trails
  • • Supply chain verification
  • • Financial records & releases
  • • Corporate governance

Personal & Privacy

  • • Personal records & ideas
  • • Identity verification
  • • Private communications
  • • Digital legacy
Technical Foundation

Our service leverages the Bitcoin blockchain's inherent properties:

  • Immutability: Once recorded, data cannot be altered or deleted
  • Decentralization: No single point of failure or control
  • Transparency: All transactions are publicly verifiable
  • Security: Protected by the world's most secure network

We commit only the 32‑byte SHA‑256 hash (hex) to an OP_RETURN output — no headers or identifiers — keeping the on‑chain commitment compact and future‑proof. Our TXT certificate includes clear, human‑readable instructions to verify with public tools or your own node.

Privacy & Control

Privacy is the default. In private mode, your text never leaves the browser — only its cryptographic fingerprint is transmitted and anchored. When you choose public mode, your text is shown alongside the verification data on the dedicated proof page.

Owner tokens let you manage visibility after creation. You control what’s public, and you can always verify independently — with or without ProofSeal.

Proof Format Specification
Technical details of how proofs are created and stored

OP_RETURN Payload

payload: 32B = content_hash (hex)

The OP_RETURN contains only the 32-byte hash (no header/magic).

Verification Instructions
How to independently verify proofs without trusting our service

Step 1: Calculate Your File's Hash

Important: For Raw Text

If you have raw text (not a file), first create a .txt file with exactly your text. Save it, then hash the file using the commands below.

Windows
# Navigate to your file's folder
cd C:\\path\\to\\your\\file
# Calculate SHA-256 hash
certutil -hashfile your-file.txt SHA256
macOS
# Navigate to your file's folder
cd /path/to/your/file
# Calculate SHA-256 hash
shasum -a 256 your-file.txt | awk {'print $1'}
Linux
# Navigate to your file's folder
cd /path/to/your/file
# Calculate SHA-256 hash
sha256sum your-file.txt | awk {'print $1'}

Step 2: Inspect OP_RETURN

Find the transaction's OP_RETURN and confirm the payload equals your 64-hex hash.

Go to mempool.space:
https://mempool.space

Step 3: Verify the Match

Success if:

  • The OP_RETURN data exactly matches your calculated hash
  • The transaction has at least 1 confirmation
  • The transaction timestamp is after you created the proof
Proof TXT Format
Human-readable certificate format for downloaded proofs
Hash (SHA-256): 2ebc80955a1b14c7859738412d4fd1b498b16580fa48bf9cf6bf7d4ca0c5a6c5 Algorithm: SHA-256 (canonicalized NFC+LF+trim) Anchored in Bitcoin: Transaction: 4b8e3a...f02c Block height: 861234 Anchored at: 2025-08-30 14:22 UTC Permanent proof page: https://proofseal.org/proof/2ebc8095... ----- BEGIN CERTIFIED TEXT ----- Hello Bitcoin world. This is my immutable statement. ----- END CERTIFIED TEXT -----
Security Considerations
Important security and privacy information

Private Mode

In private mode, your text or file never leaves the browser or your device. Only the cryptographic hash is transmitted and stored. This ensures maximum privacy while maintaining verifiability.

Raw Hash Option

If you already have a SHA-256 hash of your content, you can use the Raw Hash option to skip the file/text step entirely and anchor the hash directly.

Independent Verification

All proofs can be verified independently using your own Bitcoin node or public explorers — no trust in ProofSeal required.