SYNOPSIS

Rust to Javascript/Webassembly compilation of ethereum-bn128.rs.

Derived largely from rustbn.js and recompiled used wasm-pack

Internally it uses the Parity fork of the Zcash bn pairing cryptography library, implementing an efficient bilinear pairing on the Barreto-Naehrig (BN) curve.

It implements helpers to support the functionality defined in EIP-196 and EIP-197.

Installation

Clone this repo and build following the [Compilation] instructions below.

Usage

Import the module:

import { initRustBN } from 'rustbn'

const bn128 = await initRustBN()

Curve Addition

let inputHexString = ...
let outputHexString = bn128.ec_add(inputHexString)

Curve Multiplication

let inputHexString = ...
let outputHexString = bn128.ec_mul(inputHexString)

Curve Pairing

let inputHexString = ...
let outputHexString = bn128.ec_pairing(inputHexString)

Developer

Building the module

For basic setup:

• Install rust and wasm-pack via the wasm-pack prerequisites
• Clone this repo
• Install JS dependencies - npm i
• Run npm run build:wasm to compile the Rust code to WASM
• Run npm run wasm2b64 to convert the WASM bytecode to a base64 string consumable by the Typescript wrapper
• Run npm run build to build the final JS outputs

Build Outputs

The build process outputs both CommonJS and ESM builds of the library and specifies entry points based on the main, module, and alternatively the exports fields in package.json. Both builds start with the wasm build from wasm-bindgen which is then loaded by a Typescript wrapper of the WASM output. Our Typescript code is slightly different than the original Javascript generated by wasm-bindgen because the default ESM output would require a bundler.

License

Licensed under either of

• MIT license, (LICENSE-MIT or http://opensource.org/licenses/MIT)
• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)

at your option.

Copyright 2016 Zcash Electric Coin Company. The Zcash Company promises to maintain the "bn" crate on crates.io under this MIT/Apache-2.0 dual license.