@lookatfr3sn0/x3dh NPM

X3DH (Extended Triple Diffie-Hellman)

A TypeScript implementation of the Extended Triple Diffie-Hellman (X3DH) key agreement protocol, also known as the Signal protocol. This library uses libsodium for cryptographic operations and is designed for secure end-to-end encryption (E2EE) and key exchange.

Features

X3DH key agreement protocol
Uses libsodium for cryptography
TypeScript support
Suitable for E2EE and secure messaging

Installation

npm install @lookatfr3sn0/x3dh

Usage

// ESM (recommended)
import { X3DH } from '@lookatfr3sn0/x3dh';

// CommonJS
const { X3DH } = require('@lookatfr3sn0/x3dh');

Important Note on Hash Algorithm

Due to limitations of the underlying sodium-plus library, the sha256 and sha512 options for the hash algorithm actually use BLAKE2b under the hood. This means that while the API allows you to select sha256 or sha512, the cryptographic operations are performed using BLAKE2b with output lengths matching those of SHA-256 (32 bytes) or SHA-512 (64 bytes).