Function deriveBitsImpl

lib/internal/crypto/webcrypto.js:251–297

(algorithm, baseKey, length = null)

}

function deriveBitsImpl(algorithm, baseKey, length = null) {
  const prefix = prepareSubtleMethod(this, 'deriveBits', arguments.length, 2);
  let i = 0;
  algorithm = convertSubtleArgument(
    prefix, 'AlgorithmIdentifier', algorithm, i++);
  baseKey = convertSubtleArgument(prefix, 'CryptoKey', baseKey, i++);
  if (length !== null) {
    length = convertSubtleArgument(prefix, 'unsigned long', length, i++);
  }

  const normalizedAlgorithm = normalizeAlgorithm(algorithm, 'deriveBits');
  if (!hasCryptoKeyUsage(baseKey, 'deriveBits')) {
    throw lazyDOMException(
      'baseKey does not have deriveBits usage',
      'InvalidAccessError');
  }
  if (getCryptoKeyAlgorithm(baseKey).name !== normalizedAlgorithm.name)
    throw lazyDOMException('Key algorithm mismatch', 'InvalidAccessError');
  switch (normalizedAlgorithm.name) {
    case 'X25519':
      // Fall through
    case 'X448':
      // Fall through
    case 'ECDH':
      return require('internal/crypto/diffiehellman')
        .ecdhDeriveBits(normalizedAlgorithm, baseKey, length);
    case 'HKDF':
      return require('internal/crypto/hkdf')
        .hkdfDeriveBits(normalizedAlgorithm, baseKey, length);
    case 'PBKDF2':
      return require('internal/crypto/pbkdf2')
        .pbkdf2DeriveBits(normalizedAlgorithm, baseKey, length);
    case 'Argon2d':
      // Fall through
    case 'Argon2i':
      // Fall through
    case 'Argon2id':
      return require('internal/crypto/argon2')
        .argon2DeriveBits(normalizedAlgorithm, baseKey, length);
    /* c8 ignore start */
    default: {
      const assert = require('internal/assert');
      assert.fail('Unreachable code');
    }
    /* c8 ignore stop */
  }
}

function getKeyLength({ name, length, hash }) {
  switch (name) {