old_contents: from base64 import standard_b64encode, standard_b64decode
  
  import nacl.bindings
  import nacl.utils
  from nacl.secret import SecretBox
  
  from pymacaroons.field_encryptors.base_field_encryptor import (
      BaseFieldEncryptor
  )
  from pymacaroons.utils import (
      truncate_or_pad, convert_to_bytes, convert_to_string
  )
  
  
  class SecretBoxEncryptor(BaseFieldEncryptor):
  
      def __init__(self, signifier=None, nonce=None):
          super(SecretBoxEncryptor, self).__init__(
              signifier=signifier or 'sbe::'
          )
          self.nonce = (nonce or
              nacl.utils.random(nacl.bindings.crypto_secretbox_NONCEBYTES))
  
      def encrypt(self, signature, field_data):
          encrypt_key = truncate_or_pad(signature)
          box = SecretBox(key=encrypt_key)
          encrypted = box.encrypt(convert_to_bytes(field_data), nonce=self.nonce)
          return self._signifier + standard_b64encode(encrypted)
  
      def decrypt(self, signature, field_data):
          key = truncate_or_pad(signature)
          box = SecretBox(key=key)
          encoded = convert_to_bytes(field_data[len(self.signifier):])
          decrypted = box.decrypt(standard_b64decode(encoded))
          return convert_to_string(decrypted)
  
new_contents: from base64 import standard_b64encode, standard_b64decode
  
  import nacl.bindings
  import nacl.utils
  from nacl.secret import SecretBox
  
  from pymacaroons.field_encryptors.base_field_encryptor import (
      BaseFieldEncryptor
  )
  from pymacaroons.utils import (
      truncate_or_pad, convert_to_bytes, convert_to_string
  )
  
  
  class SecretBoxEncryptor(BaseFieldEncryptor):
  
      def __init__(self, signifier=None, nonce=None):
          super(SecretBoxEncryptor, self).__init__(
              signifier=signifier or 'sbe::'
          )
          self.nonce = nonce or nacl.utils.random(
              nacl.bindings.crypto_secretbox_NONCEBYTES
          )
  
      def encrypt(self, signature, field_data):
          encrypt_key = truncate_or_pad(signature)
          box = SecretBox(key=encrypt_key)
          encrypted = box.encrypt(convert_to_bytes(field_data), nonce=self.nonce)
          return self._signifier + standard_b64encode(encrypted)
  
      def decrypt(self, signature, field_data):
          key = truncate_or_pad(signature)
          box = SecretBox(key=key)
          encoded = convert_to_bytes(field_data[len(self.signifier):])
          decrypted = box.decrypt(standard_b64decode(encoded))
          return convert_to_string(decrypted)
  
subject: Break how flake8 wants me to break