API Reference

Email-Based Hash Timestamping

For users who want to maintain complete privacy over their documents and avoid uploading any files to Simple Proof’s servers, we offer a hash-only timestamping workflow via email. This method allows clients to submit pre-computed SHA-256 hashes in a CSV file for blockchain anchoring.

Command Format

To activate this mode, the email must include the following subject line:

[timestamp hashes]

This command triggers Simple Proof’s hash-based timestamping logic.

Required CSV Attachment Format

Attach a .csv file containing one hash per line, following the structure below:

CSV Format

SHA-256 Hash,File Name,Extension
2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae,doc1,pdf
fe153b443e0413d832da5ad503490f88e12b2eae8576d0b29a9fd8f2e8e8cd51,contract_a,docx
c9a2a6e19a4c12482c18b7b365d2b88f59d12cbb8f627de9f13ee6e7cbe56d33,scan123,png
  • SHA-256 Hash: Required. Must be a 64-character hexadecimal string.
  • File Name: Optional. Used as a label for reporting and display purposes.
  • Extension: Optional. Helps classify the type of file associated with the hash.

Important: Any row with an invalid or missing hash will be skipped.

Generating the CSV File

To simplify the creation of the required CSV file, you can use our dedicated tool:

https://filehash.simpleproof.xyz

This lightweight web app allows you to:

  • Select multiple files from your device.
  • Generate SHA-256 hashes locally (no files are ever uploaded).
  • Download a pre-formatted .csv file ready for email submission.

The application runs entirely in your browser, supports offline usage via Progressive Web App (PWA) features, and is designed with privacy in mind. You can also inspect or contribute to its open-source code available on GitHub.

Process Overview

  1. Email Processing
    • The system parses the attached CSV file and extracts valid hashes.
    • In addition to all hashes in the CSV, the entire email content (subject, body, metadata) is also hashed and submitted for timestamping.
  2. Blockchain Submission
    • All collected hashes are submitted to the OpenTimestamps protocol, which anchors them in the Bitcoin blockchain.
    • SimpleProof waits for at least 3 confirmations before notifying users to ensure irreversible inclusion.
  3. Notifications
    • An initial email is sent acknowledging receipt and listing the hashes processed.
    • A final confirmation email is sent once the data is fully confirmed on-chain, including verification links.

Example Email Flow

📥 Acknowledgment Email

Subject: [SimpleProof] Hash Submission Received

Body:
We've received your hash list and it's currently being anchored to the Bitcoin blockchain.

Once confirmed, you’ll receive a final email with verification links for each hash.

[Summary + Temporary Verification URLs]

✅ Confirmation Email

Subject: [SimpleProof] Hashes Confirmed on the Blockchain

Body:
Your submitted hashes have received at least 3 confirmations on the Bitcoin blockchain.

Click below to verify each timestamp:

[SHA-256 Hash + Confirmation Time + Permanent Verification URLs]

Benefits

  • Full Privacy: No documents are uploaded or stored—only SHA-256 hashes are timestamped.
  • Verifiable Proof: Every hash is cryptographically anchored to Bitcoin and publicly verifiable.
  • Flexible Labeling: Optional metadata (file name, extension) allows traceability without compromising content privacy.