@crpdo/key/lib/sign-key.js

Streamlines key generation, derivation, and management through its simple and intuitive API

const Nacl = require('@crpdo/crypto/nacl')
const BaseKey = require('./base-key')

/**
 * This class extends BaseKey and provides methods for signing and verifying messages
 * using the Nacl library. The messages are signed using the privateKey property of 
 * the SignKey instance, and they can be verified using a given publicKey or the 
 * publicKey property of the SignKey instance.
 */
class SignKey extends BaseKey {
  /**
   * @param {string} seed - A seed string used to create the SignKey
   */
  constructor(seed) {
    super(Nacl.createSignKey(seed))
  }

  /**
   * @param {string} data - The data to sign
   * @returns {string} - The signed data
   */
  sign(data) {
    return Nacl.sign(data, this.key.privateKey)
  }

  /**
   * @param {string} data - The data to verify
   * @param {string} signature - The signature to check the data against
   * @param {string} [publicKey] - The public key to use for verification. 
   * If not provided, the publicKey of the SignKey instance is used.
   * @returns {boolean} - Returns true if the signature is valid, false otherwise
   */
  verify(data, signature, publicKey) {
    return Nacl.verify(data, signature, publicKey || this.key.publicKey)
  }

  /**
   * Generates a SignKey from a given HDKey
   * @param {object} hd - An HDKey instance
   * @returns {SignKey} - A new SignKey instance
   */
  static fromHdKey(hd) {
    const seed = hd.privateExtendedKey
    return new SignKey(seed)
  }
}

module.exports = SignKey