code: function handleCipher(opts, err) {
    if (err) {
      switch (err.name) {
        case nodecipher.errors.BAD_ALGORITHM:
          handleInvalidAlgorithm(opts, err);
          break;
        case nodecipher.errors.BAD_DIGEST:
          handleInvalidHash(opts, err);
          break;
        case nodecipher.errors.BAD_FILE:
          handleEnoentError(opts, err);
          break;
        case nodecipher.errors.BAD_DECRYPT:
          handleBadDecrypt(opts, err);
          break;
        default:
          handleUnknownErrors(opts, err);
      }
      process.exit(1);
    } else {
      handleCipherSuccess(opts, err);
    }
  }
docs: Called when the cipher has completed. Handles errors if there are any.
  
  @param {Object} opts
  @param {Error|null} err