Bitcoin Signature Verifier

A dependency-free Bitcoin message signature verifier that works in browsers without requiring npm install.

Features

• Zero Dependencies: Pure TypeScript implementation with no external dependencies
• Browser Compatible: Works directly in modern browsers using ES modules
• Client-Side Verification: Verifies signatures entirely in the browser
• Simple API: Clean TypeScript interface for programmatic use
• Unit Tests: Includes a test suite for the verification logic

Things you can do

Offline

Visit the live page, then you can test offline mode in Chrome (webkit browsers) by opening Developer Tools (F12)

• Network
• Change "No Throttling" -> "Offline"

Clone the repository

Download Bun, JS runtime

git clone https://github.com/mothepro/verify-bitcoin-message
cd verify-bitcoin-message
bun install
bun test

Serve locally

bun run build:browser
python -m http.server 8000 static # Any "server" is fine. Since it requires ES modules and Web Crypto API support

CDN

<script type="module">
  import verify, { verifySafe } from 'https://unpkg.com/verify-bitcoin-message';
</script>

Command Line Interface

npx verify-bitcoin-message --json \
   --address 1F3sAm6ZtwLAUnj7d38pGFxtP3RVEvtsbV \
   --message "This is an example of a signed message." \
   --signature "H9L5yLFjti0QTHhPyFrZCT1V/MMnBtXKmoiKDZ78NDBjERki6ZTQZdSMCtkgoNmp17By9ItJr8o7ChX0XxY91nk="

Programmatic Use

import verify from 'verify-bitcoin-message';

const isValid = await verify({
  address: '1F3sAm6ZtwLAUnj7d38pGFxtP3RVEvtsbV',
  message: 'This is an example of a signed message.',
  signature: 'H9L5yLFjti0QTHhPyFrZCT1V/MMnBtXKmoiKDZ78NDBjERki6ZTQZdSMCtkgoNmp17By9ItJr8o7ChX0XxY91nk='
});

Or, if you're not a fan of throwing errors:

import { verifySafe } from 'verify-bitcoin-message';

const isValid = await verifySafe({
  address: '1F3sAm6ZtwLAUnj7d38pGFxtP3RVEvtsbV',
  message: 'This is an example of a signed message.',
  signature: 'H9L5yLFjti0QTHhPyFrZCT1V/MMnBtXKmoiKDZ78NDBjERki6ZTQZdSMCtkgoNmp17By9ItJr8o7ChX0XxY91nk='
});

Deployment

This project uses GitHub Actions for automatic deployment to GitHub Pages:

• Automatic: Deploys on every push to main branch
• Tested: Runs bun test before deployment
• Built: Runs bun run build:browser to create static/verify.js
• Complete: Includes both source files and built JavaScript in deployment

The workflow ensures that only tested, working code gets deployed.

Implementation Notes

This is a complete, production-ready implementation of Bitcoin message signature verification:

1. Full secp256k1 implementation: Complete elliptic curve operations from scratch
2. Complete RIPEMD-160: Pure TypeScript implementation following RFC 1320
3. Complete signature recovery: Handles all Bitcoin signature formats and recovery IDs
4. Zero dependencies: Works in browsers without any external dependencies

All cryptographic functions are implemented from publicly available specifications in pure TypeScript.

Up Next

• [ ] better error messages
• [ ] better ui (i.e. the signed page should look nice and doesn't need to be a form)
• [ ] more support for address types
• [ ] explainer what this is, how, and why (why cold storage >>> exchanges)
• [ ] service worker?
• [ ] move this to readme

Alternatives

https://www.bitcoin.com/tools/verify-message/ https://www.verifybitcoinmessage.com/ https://bluewallet.github.io/VerifySignature