code: function cipher(command, input, output, options) {
    if (_.isUndefined(options.password)) {
      prompForPassword(password => {
        cipher(command, input, output, options, _.assign(options, { password }));
      });
    } else {
      let opts = _.assign(parseOptions(options), { input, output });
  
      nodecipher[command](opts, err => {
        handleCipher(opts, err);
      });
    }
  }
docs: First checks if the password has been supplied. If not, the user is prompted
  to provide one. Once the password is received, parse the options and then
  call the appropriate NodeCipher method with the given options.
  
  @see prompForPassword
  @see handleCipher
  @param {string} command
  @param {string} input
  @param {string} output
  @param {Object} Options