Knuth JS-WASM

Bitcoin Cash WebAssembly library for browsers and Node.js

Knuth JS-WASM brings the power of a full Bitcoin Cash node to JavaScript through WebAssembly. Build wallets, validate addresses, create transactions, and more — all running natively in the browser or Node.js.

Installation

npm install @knuth/js-wasm

Quick Start

import { PaymentAddress, Wallet, Kth } from '@knuth/js-wasm';

// Check library info
const config = Kth.getLibconfig();
console.log(`Knuth WASM v${config.wasmLibraryVersion}`);

// Validate and convert addresses
const addr = PaymentAddress.fromString('bitcoincash:qpm2qsznhks23z7629mms6s4cwef74vcwvy22gdx6a');
if (addr) {
    console.log(`Cash Address: ${addr.encodedCashAddr()}`);
    console.log(`Legacy: ${addr.encodedLegacy()}`);
    console.log(`CashTokens: ${addr.encodedCashTokens()}`);
}

Features

Address Handling

Convert between address formats and validate addresses:

import { PaymentAddress } from '@knuth/js-wasm';

// Parse any format (CashAddr, Legacy, CashTokens)
const addr = PaymentAddress.fromString('1P3GQYtcWgZHrrJhUa4ctoQ3QoCU2F65nz');

if (addr) {
    console.log(addr.encodedCashAddr());    // bitcoincash:qrcuqadqrzp2uztjl9wn5sthepkg22majyxw4gmv6p
    console.log(addr.encodedLegacy());      // 1P3GQYtcWgZHrrJhUa4ctoQ3QoCU2F65nz
    console.log(addr.encodedCashTokens());  // bitcoincash:zrcuqadqrzp2uztjl9wn5sthepkg22majypyxk429j
}

// Validate addresses
const isValid = PaymentAddress.isValid('bitcoincash:qrcuqadqrzp2uztjl9wn5sthepkg22majyxw4gmv6p');
console.log(isValid); // true

HD Wallet

Generate addresses from a BIP39 mnemonic:

import { Wallet } from '@knuth/js-wasm';

// Your 12 or 24-word BIP39 mnemonic
const mnemonic = ['word1', 'word2', 'word3', '...', 'word12'];
const derivationPath = "m/44'/145'/0'/0";
const network = 'MAINNET';

const wallet = Wallet.fromMnemonic(mnemonic, derivationPath, network);

// Get a single address
const address = await wallet.getAddress(0);
console.log(address.encoded()); // bitcoincash:qr9sawzzmstkluq9nqefsu7eqya4zk2w7udune2pmf

// Get multiple addresses
const addresses = await wallet.getAddresses(5);
addresses.forEach((addr, i) => {
    console.log(`[${i}]: ${addr.encoded()}`);
});

Transactions

Parse and inspect transactions:

import { Transaction, hexStrToBytes, encodeHash } from '@knuth/js-wasm';

const txHex = '0100000001c997a5e56e104102fa209c6a852dd90660a20b2d9c352423edce25857fcd3704000000004847304402204e45e16932b8af514961a1d3a1a25fdf3f4f7732e9d624c6c61548ab5fb8cd410220181522ec8eca07de4860a4acdd12909d831cc56cbbac4622082221a8768d1d0901ffffffff0200ca9a3b00000000434104ae1a62fe09c5f51b13905f07f06b99a2f7159b2225f374cd378d71302fa28414e7aab37397f554a7df5f142c21c1b7303b8a0626f1baded5c72a704f7e6cd84cac00286bee0000000043410411db93e1dcdb8a016b49840f8c53bc1eb68a382e97b1482ecad7b148a6909a5cb2e0eaddfb84ccf9744464f82e160bfa9b8b64f9d4c03f999b8643f656b412a3ac00000000';

const tx = Transaction.fromData(hexStrToBytes(txHex));
if (tx) {
    console.log(`TxID: ${encodeHash(tx.hash)}`);
    console.log(`Size: ${tx.serializedSize(true)} bytes`);
    console.log(`Inputs: ${tx.inputs?.length}`);
    console.log(`Outputs: ${tx.outputs?.length}`);
}

Scripts

Work with Bitcoin scripts:

import { Script, hexStrToBytes } from '@knuth/js-wasm';

// Parse a P2PKH script
const scriptBytes = hexStrToBytes('76a91406ccef231c2db72526df9338894ccf9355e8f12188ac');
const script = Script.fromData(scriptBytes, false);

if (script) {
    console.log(`Type: ${script.type}`);           // pay_public_key_hash
    console.log(`Size: ${script.serializedSize}`); // 25
    console.log(script.toString(0));               // dup hash160 [...] equalverify checksig
}

// Create scripts from string
const multisig = Script.fromString('2 [pubkey1] [pubkey2] [pubkey3] 3 checkmultisig');

Hashing

Cryptographic hash functions:

import { HashFunctions } from '@knuth/js-wasm';

const message = new Uint8Array([72, 101, 108, 108, 111]); // "Hello"

const sha256 = HashFunctions.sha256(message);
const sha256Str = HashFunctions.sha256Str(message);
const ripemd160 = HashFunctions.ripemd160(message);
const hash160 = HashFunctions.hash160(message); // SHA256 + RIPEMD160

CashTokens Support

Parse transactions with fungible and non-fungible tokens:

import { Transaction, hexStrToBytes, encodeHash } from '@knuth/js-wasm';

const tx = Transaction.fromData(hexStrToBytes(tokenTxHex));
if (tx && tx.outputs) {
    const output = tx.outputs[0];

    if (output.tokenData) {
        console.log(`Category: ${encodeHash(output.tokenData.category)}`);
        console.log(`Kind: ${output.tokenData.kind}`); // 'fungible' or 'non_fungible'

        if (output.tokenData.kind === 'fungible') {
            console.log(`Amount: ${output.tokenData.data.amount}`);
        }
    }
}

Live Demo

Try it in your browser at kth.cash — no installation required!

API Reference

Core Classes

Class	Description
PaymentAddress	Address parsing, validation, and format conversion
Wallet	HD wallet with BIP39/BIP44 support
Transaction	Transaction parsing, creation, and serialization
Script	Bitcoin script handling and verification
HashFunctions	SHA256, RIPEMD160, Hash160, and more
Kth	Library configuration and version info

Utilities

Function	Description
hexStrToBytes(hex)	Convert hex string to Uint8Array
bytesToHexStr(bytes)	Convert Uint8Array to hex string
encodeHash(hash)	Encode hash as hex string (reversed)
decodeHash(hex)	Decode hex string to hash (reversed)
bitcoinToSatoshis(btc)	Convert BCH to satoshis
satoshisToBitcoin(sats)	Convert satoshis to BCH

Browser Usage

<script src="https://unpkg.com/@knuth/js-wasm/src/kth.js"></script>
<script>
    // Wait for WASM to load
    Module.onRuntimeInitialized = () => {
        const addr = PaymentAddress.fromString('bitcoincash:qpm2qsznhks23z7629mms6s4cwef74vcwvy22gdx6a');
        console.log(addr.encodedLegacy());
    };
</script>

Requirements

• Node.js 16+ or modern browser with WebAssembly support
• ES2020+ (uses BigInt for satoshi values)

Issues

Please report issues in our main repository.

License

MIT License - see LICENSE.md

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