Certify Solana

A lightweight tool to certify text or files on the Solana blockchain using the Memo program. Creates an immutable, timestamped proof of existence for any content by recording its SHA-256 hash on-chain.

Use Cases

• Document certification: Prove a document existed at a specific point in time
• Intellectual property: Timestamp creative works, code, or inventions
• Audit trails: Create verifiable records for compliance purposes
• Data integrity: Verify files haven't been modified since certification

How It Works

1. The tool computes a SHA-256 hash of your text or file
2. Optionally prepends a timestamp to ensure uniqueness
3. Records the hash on Solana's blockchain via the Memo program
4. Returns a transaction signature as proof of certification

The resulting transaction is permanent and publicly verifiable on any Solana explorer.

Requirements

• Node.js >= 20.0.0
• A Solana wallet with a small amount of SOL (< 0.001 SOL per transaction)

Installation

git clone git@github.com:floflo777/certify-solana.git
cd certify-solana
npm install
cp .env.template .env

Configuration

Environment Variables

Add your Solana private key to .env:

PRIVATE_KEY=your_private_key_here

Supported formats:

• Base58 encoded string
• JSON array of bytes ([1,2,3,...])
• Mnemonic phrase (BIP39)

Settings

Edit config.json to configure the certification mode:

{
  "hashType": {
    "text": true,
    "file": false
  },
  "path": "document.pdf",
  "timestamp": true
}

Parameter	Description
hashType.text	Set to true to certify text (hardcoded in src/certif.js)
hashType.file	Set to true to certify a file
path	Path to the file to certify (when hashType.file is true)
timestamp	Prepend ISO timestamp to ensure unique hashes for identical content

Usage

node src/certif.js

Output:

Transaction ABC123... confirmed
Hash of file document.pdf has been recorded on Solana's blockchain.

Verifying a Certification

1. Note the transaction signature from the output
2. Visit Solana Explorer
3. Search for the transaction signature
4. The memo field contains your SHA-256 hash

To verify a document, compute its hash with the same parameters and compare it to the on-chain record.

Architecture

certify-solana/
├── src/
│   ├── certif.js      # Main certification logic
│   └── hashFile.js    # File hashing utility
├── config.js          # Configuration loader
├── config.json        # User settings
└── .env               # Private key (not committed)

License

MIT