static nonce() {
    return crypto
      .randomBytes(16)
      .toString('base64')
      .replace(URLSAFE_BASE64_PLUS_REGEX, '-') // make it url safe
      .replace(URLSAFE_BASE64_SLASH_REGEX, '_')
      .replace(URLSAFE_BASE64_TRAILING_EQUAL_REGEX, '')
      .toString('ascii')
  }
In cryptography, a nonce is an arbitrary number that can be used just once.
It is similar in spirit to a nonce * word, hence the name. It is often a random or pseudo-random
number issued in an authentication protocol to * ensure that old communications cannot be reused
in replay attacks.

@returns {String}