def public(self, data):
"""Public Key Transform: encrypt, verify
Args:
data: str of bytestring to transform
Returns:
str: of bytestring of transformed `data`
Raises:
ValueError: Data too long for key size.
"""
message = integers.bytes_to_int(data)
if self.modulus <= message:
raise ValueError, "data too long for key size"
cypher = pow(message, self.exponent, self.modulus)
return integers.int_to_bytes(cypher)
def private(self, data):
"""Private Key Transform: decrypt, sign
Args:
data: str of bytestring to transform
Returns:
str: of bytestring of transformed `data`
Raises:
ValueError: Data too long for key size.
AttributeError: No private component in encryption key.
"""
cypher = integers.bytes_to_int(data)
if self.modulus <= cypher:
raise ValueError, "Data too long for key size."
elif not self.decrypt:
raise AttributeError, "No private component in encryption key."
message = pow(cypher, self.decrypt, self.modulus)
return integers.int_to_bytes(message)
def make_value_from_datastore(self, value):
if value is None:
return None
return integers.bytes_to_int(value)