lazyxchacha-js

Lazy XChaCha20-Poly1305 in JavaScript (WebAssembly) based on lazyxchacha and RustCrypto: ChaCha20Poly1305.

• Key exchange: X25519
• Encryption: XChaCha20-Poly1305
• Ciphertext layout: nonce (24 bytes) + ciphertext

Installation

npm install lazyxchacha

Usage

Generate a key pair

const lazyxchacha = require("lazyxchacha");

const keypair = lazyxchacha.new_keypair();
console.log("pk:", keypair.pk); // hex string
console.log("sk:", keypair.sk); // hex string

Key exchange (X25519)

const clientKp = lazyxchacha.new_keypair();
const serverKp = lazyxchacha.new_keypair();

// Client side
const clientSharedKey = lazyxchacha.shared_key(serverKp.pk, clientKp.sk);
// Server side
const serverSharedKey = lazyxchacha.shared_key(clientKp.pk, serverKp.sk);

// clientSharedKey === serverSharedKey

Encrypt / Decrypt (hex string)

const sharedKey = lazyxchacha.shared_key(serverKp.pk, clientKp.sk);

const ciphertext = lazyxchacha.encrypt("Hello lazyxchacha-js", sharedKey); // hex string
const plaintext = lazyxchacha.decrypt(ciphertext, sharedKey);

console.log("ciphertext:", ciphertext);
console.log("plaintext:", plaintext);

Encrypt / Decrypt (bytes)

const ciphertext = lazyxchacha.encrypt_bytes("Hello lazyxchacha-js", sharedKey); // Uint8Array
const plaintext = lazyxchacha.decrypt_bytes(ciphertext, sharedKey); // string

Encrypt / Decrypt (raw binary)

const data = new Uint8Array([1, 2, 3, 4, 5]);

const ciphertext = lazyxchacha.encrypt_raw(data, sharedKey); // Uint8Array
const plaintext = lazyxchacha.decrypt_raw(ciphertext, sharedKey); // Uint8Array

Hex helpers

const hex = lazyxchacha.to_hex(new TextEncoder().encode("Hello")); // "48656c6c6f"
const bytes = lazyxchacha.from_hex(hex); // Uint8Array

API

| Function | Parameters | Returns | |---|---|---| | new_keypair() | - | KeyPair { pk, sk } (hex strings) | | shared_key(pk, sk) | hex strings | shared key as hex string | | encrypt(plaintext, key) | string, hex key | hex string | | decrypt(ciphertext, key) | hex string, hex key | string | | encrypt_bytes(plaintext, key) | string, hex key | Uint8Array | | decrypt_bytes(ciphertext, key) | Uint8Array, hex key | string | | encrypt_raw(plaintext, key) | Uint8Array, hex key | Uint8Array | | decrypt_raw(ciphertext, key) | Uint8Array, hex key | Uint8Array | | to_hex(bytes) | Uint8Array | hex string | | from_hex(hex) | hex string | Uint8Array |

Supported types across the JS/wasm boundary: https://rustwasm.github.io/docs/wasm-bindgen/reference/types.html

Development

# Build (Node.js target)
make build

# Test in headless browsers
make test

# Publish to npm
make publish

License

See LICENSE.