docs: def _key_digest(self, secret_key):
          
          '''
              a helper method for creating a base 64 encoded secret key and digest
          :param secret_key: string with key to encrypt/decrypt data
          :return: string with base64 key, string with base64 digest
          '''
          
          from hashlib import md5, sha256
          from base64 import b64encode
          key_bytes = sha256(secret_key.encode('utf-8')).digest()
          key_b64 = b64encode(key_bytes).decode()
          digest_bytes = md5(key_bytes).digest()
          digest_b64 = b64encode(digest_bytes).decode()
          
          return key_b64, digest_b64