js-waku/src/lib/enr/keypair/index.ts

import { keys } from "libp2p-crypto";
import mh from "multihashes";
import PeerId from "peer-id";

const { keysPBM, supportedKeys } = keys;

import { ERR_TYPE_NOT_IMPLEMENTED } from "./constants";
import { Secp256k1Keypair } from "./secp256k1";
import { IKeypair, KeypairType } from "./types";

export * from "./types";
export * from "./secp256k1";

export async function generateKeypair(type: KeypairType): Promise<IKeypair> {
  switch (type) {
    case KeypairType.secp256k1:
      return await Secp256k1Keypair.generate();
    default:
      throw new Error(ERR_TYPE_NOT_IMPLEMENTED);
  }
}

export function createKeypair(
  type: KeypairType,
  privateKey?: Buffer,
  publicKey?: Buffer
): IKeypair {
  switch (type) {
    case KeypairType.secp256k1:
      return new Secp256k1Keypair(privateKey, publicKey);
    default:
      throw new Error(ERR_TYPE_NOT_IMPLEMENTED);
  }
}

export function createPeerIdFromKeypair(keypair: IKeypair): PeerId {
  switch (keypair.type) {
    case KeypairType.secp256k1: {
      // manually create a peer id to avoid expensive ops
      const privKey = keypair.hasPrivateKey()
        ? new supportedKeys.secp256k1.Secp256k1PrivateKey(
            keypair.privateKey,
            keypair.publicKey
          )
        : undefined;

      const pubKey = new supportedKeys.secp256k1.Secp256k1PublicKey(
        keypair.publicKey
      );
      const id = mh.encode(pubKey.bytes, "identity");
      return new PeerId(id, privKey, pubKey);
    }
    default:
      throw new Error(ERR_TYPE_NOT_IMPLEMENTED);
  }
}

export function createKeypairFromPeerId(peerId: PeerId): IKeypair {
  // pub/private key bytes from peer-id are encoded in protobuf format
  const pub = keysPBM.PublicKey.decode(peerId.pubKey.bytes);
  return createKeypair(
    pub.Type as KeypairType,
    peerId.privKey ? Buffer.from(peerId.privKey.marshal()) : undefined,
    Buffer.from(pub.Data)
  );
}