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

Docs: Getting Started →

API Reference

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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).

Quick Start

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');

See Installation for more guidance on getting set up.


These guides introduce some of the high-level concepts and functionality provided by Libauth.

More Examples

In addition to the usage examples in these guides, note that Libauth includes comprehensive tests that can help demonstrate usage of all functionality.

For example, utilities related to hexadecimal-encoded strings are defined in hex.ts; for thorough usage examples, see the co-located hex.spec.ts. You can also use GitHub search to see how a particular utility is used throughout the library, e.g. splitEvery.

API Overview

Below is a partial selection of functionality provided by Libauth. If you're looking for something else, be sure to search the API Reference.

High-level utilities are composed from lower-level utilities which are also exported, so it's often possible to remix behavior in your own codebase with relatively little duplication or maintenance burden. See the Defined in ... link on each utility's API reference page to review and copy the implementation.

Table of Contents

Address Formats

Base58 Addresses



CashAddress-like Formats



Base-N Conversion


Binary Strings (e.g. 00101010)

Hex (Hexadecimal-Encoded Strings)



CompactUint (A.K.A. "VarInt" or "CompactSize")
Satoshi Values
VM Numbers (A.K.A. "ScriptNum")





BIP32 Hierarchical Deterministic (HD) Keys

BIP39 Mnemonic Phrases

Wallet Import Format (WIF)

Key Utilities

P2P Messages

Decoding Utilities



Dust Calculation

Virtual Machines

Built-In VMs



Wallet Engine

Bitcoin Cash Metadata Registries (BCMRs)

CashAssembly Language & Compiler

Multi-Party Compilation

P2PKH Utilities

Wallet Templates

VMB Tests

Libauth's test suite includes a set of cross-implementation Virtual Machine Bytecode (VMB) test vectors for each supported VM. See Libauth VMB Tests for details.


CashAssembly is the assembly language used by Libauth's Wallet Templates. To learn more about CashAssembly, read the Bitauth IDE Guide.


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

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