x25519.wasm

WebAssembly port of X25519

npm i @hazae41/x25519.wasm

Node Package 📦

Features

• Reproducible building
• Pre-bundled and streamed
• Zero-copy memory slices

Modules

• x25519-dalek

Algorithms

• X25519

Usage

import { X25519Wasm, X25519StaticSecret } from "@hazae41/x25519.wasm";

// Wait for WASM to load
await X25519Wasm.initBundled();

// Generate secret x for Alice
using secretx = new X25519StaticSecret()

// Generate secret y for Bob
using secrety = new X25519StaticSecret()

// Get public X for Alice to send to Bob
using publicx = secretx.to_public()

// Get public Y for Bob to send to Alice
using publicy = secrety.to_public()

// Alice computes the shared key S from x and Y
using sharedx = secretx.diffie_hellman(publicy)

// Bob computes the shared key S from y and X
using sharedy = secrety.diffie_hellman(publicx)

using sharedx_memory = sharedx.to_bytes()
using sharedy_memory = sharedy.to_bytes()

// S is the same for Alice and Bob
console.log("S (Alice)", sharedx_memory.bytes)
console.log("S (Bob", sharedy_memory.bytes)

Building

Unreproducible building

You need to install Rust

Then, install wasm-pack

cargo install wasm-pack

Finally, do a clean install and build

npm ci && npm run build

Reproducible building

You can build the exact same bytecode using Docker, just be sure you're on a linux/amd64 host

docker compose up --build

Then check that all the files are the same using git status

git status --porcelain

If the output is empty then the bytecode is the same as the one I commited

Automated checks

Each time I commit to the repository, the GitHub's CI does the following:

• Clone the repository
• Reproduce the build using docker compose up --build
• Throw an error if the git status --porcelain output is not empty

Each time I release a new version tag on GitHub, the GitHub's CI does the following:

• Clone the repository
• Do not reproduce the build, as it's already checked by the task above
• Throw an error if there is a npm diff between the cloned repository and the same version tag on NPM

If a version is present on NPM but not on GitHub, do not use!