BLS HD Key Utilities

Utility functions for managing BLS heirarchical deterministic accounts.

1. Create a master private key from entropy
2. Create a child private key from a private key and index
3. Convert a standard path into an array of indices
4. Create a decendent private key from a private key and array of indices

Implementation is following EIPS: EIP-2334, EIP-2333

For a higher-level interface, see @chainsafe/bls-keygen.

Example

import {deriveMasterSK, deriveChildSK, deriveChildSKMultiple, pathToIndices} from "@chainsafe/bls-hd-key";

// Create master private key (according to EIP-2333)

const entropy: Buffer = Buffer.from(...);
const masterKey: Buffer = deriveMasterSK(entropy);

// Create child private key one level deep

const childIndex: number = ...;
const childKey: Buffer = deriveChildSK(masterKey, childIndex);

// Convert a "path" into an array of indices (using validation rules of EIP-2334)

cont path = "m/12381/3600/0/0";
const childIndices: number[] = pathToIndices(path);

// Convert a "path" into an array of indices (validating an alternate key type)

const eth1KeyType = 60;
cont path = "m/12381/60/0/0";
const childIndices: number[] = pathToIndices(path, eth1KeyType);

// Create a child private key `childIndices.length` levels deep

const childIndices: number[] = [...];
const childKey = deriveChildSKMultiple(masterKey, childIndices);

// Compose functions to derive a child key from entropy and a path

const entropy: Buffer = Buffer.from(...);
cont path = "m/12381/3600/0/0";
const childKey = deriveChildSKMultiple(deriveMasterSK(entropy), pathToIndices(path));

Contrubuting

Requirements:

• nodejs
• yarn

yarn install
yarn run test

Audit

This repo was audited by Least Authority as part of this security audit, released 2020-03-23. Commit 767c998 verified in the report.

License

Apache-2.0