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An ultra-lightweight JavaScript library for Bitcoin Cash, Bitcoin, and Bitauth applications.

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An ultra-lightweight JavaScript library for Bitcoin Cash, Bitcoin, and Bitauth applications.

Libauth has no dependencies and works in all JavaScript environments, including Node.js, Deno, and browsers.


Libauth is designed to be flexible, lightweight, and easily auditable. Rather than providing a single, overarching, object-oriented API, all functionality is composed from simple functions. This has several benefits:

  • Flexibility – Even highly-complex functionality is built-up from simpler functions. These lower-level functions can be used to experiment, tweak, and remix your own higher-level methods without maintaining a fork of the library.
  • Smaller application bundles – Applications can import only the methods they need, eliminating the unused code (via dead-code elimination).
  • Better auditability – Beyond having no dependencies of its own, Libauth's functional programming approach makes auditing critical code easier: smaller bundles, smaller functions, and less churn between versions (fewer cascading changes to object-oriented interfaces).
  • Fully-portable – No platform-specific APIs are ever used, so the same code paths are used across all JavaScript environments (reducing the auditable "surface area" and simplifying library development).

Getting Started

To get started, install @bitauth/libauth:

npm install @bitauth/libauth
# OR
yarn add @bitauth/libauth

And import the functionality you need:

import { secp256k1 } from '@bitauth/libauth';
import { msgHash, pubkey, sig } from './somewhere';

secp256k1.verifySignatureDERLowS(sig, pubkey, msgHash)
? console.log('🚀 Signature valid')
: console.log('❌ Signature invalid');

Note, Libauth is a pure ESM package, so Node.js v12 or higher is required (or Deno), and using ESM is recommended.

Web Usage

For web projects, a bundler with dead-code elimination (A.K.A. "tree shaking") is strongly recommended – Libauth is designed to minimize application code size, and dead-code elimination will improve load performance in nearly all applications.

Consider Vite, Parcel, Rollup, Webpack, or a bundler designed for your web framework.

Deno Usage

Deno is a great runtime for working with Libauth. You can import the library from unpkg.com:

import { hexToBin } from 'https://unpkg.com/@bitauth/libauth/build/index.js';


Typescript Types

Libauth uses BigInt, WebAssembly, and es2017 features for some functionality. To type-check this library in you application (without skipLibCheck), your tsconfig.json will need a minimum target of es2020 or lib must include es2017 and esnext.bigint. If your application is not already importing types for WebAssembly, you may also need to add dom to lib.


Pull Requests welcome! Please see CONTRIBUTING.md for details.

This library requires Yarn for development. If you don't have Yarn, make sure you have Node.js installed, then run npm install -g yarn. Once Yarn is installed:

# note the use of --recursive to clone submodules
git clone --recursive https://github.com/bitauth/libauth.git
cd libauth

Libauth uses Yarn's Zero-Installs strategy – all of Libauth's dependencies are tracked in an independent git repository, and the dependency repo is automatically shallow-cloned into the .yarn directory.

Try running the test suite:

yarn test

You can also run the benchmarks (this will take a while):

yarn bench

During development, you may find it helpful to use the watch tasks:

# rebuild everything on save:
yarn watch
# run a subset of tests:
yarn watch:test --match='*encode*' --match='*decode*' --match='!*[script_tests]*' --match='!*[vmb_tests]*'

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