def _dec(self, cipher: Tuple[int, ...],
sk: RSA.RsaKey) -> Tuple[int, List[int]]:
decrypt = PersistentLocals(PKCS1_OAEP.new(sk, hashAlgo=SHA256).decrypt)
plain = int.from_bytes(decrypt(
self.unpack_to_byte_array(cipher, cfg.cipher_chunk_size,
cfg.cipher_bytes_payload)),
byteorder='big')
rnd_bytes = decrypt.locals['seed']
rnd = self.pack_byte_array(rnd_bytes, cfg.rnd_chunk_size)
return plain, rnd
def _enc(self, plain: int, _: int, target_pk: int) -> Tuple[List[int], List[int]]:
pub_key = RSA.construct((target_pk, self.default_exponent))
encrypt = PersistentLocals(PKCS1_v1_5.new(pub_key).encrypt)
cipher_bytes = encrypt(plain.to_bytes(32, byteorder='big'))
cipher = self.pack_byte_array(cipher_bytes, cfg.cipher_chunk_size)
rnd_bytes = encrypt.locals['ps']
assert len(rnd_bytes) == cfg.rnd_bytes
rnd = self.pack_byte_array(rnd_bytes, cfg.rnd_chunk_size)
return cipher, rnd
def _dec(self, cipher: Tuple[int, ...], sk: RSA.RsaKey) -> Tuple[int, List[int]]:
decrypt = PersistentLocals(PKCS1_v1_5.new(sk).decrypt)
ret = decrypt(self.unpack_to_byte_array(cipher, cfg.cipher_chunk_size, cfg.cipher_bytes_payload), None)
if ret is None:
raise RuntimeError("Tried to decrypt invalid cipher text")
plain = int.from_bytes(ret, byteorder='big')
rnd_bytes = decrypt.locals['em'][2:decrypt.locals['sep']]
assert len(rnd_bytes) == cfg.rnd_bytes
rnd = self.pack_byte_array(rnd_bytes, cfg.rnd_chunk_size)
return plain, rnd
def _enc(self, plain: int, _: int,
target_pk: int) -> Tuple[List[int], List[int]]:
pub_key = RSA.construct((target_pk, self.default_exponent))
encrypt = PersistentLocals(
PKCS1_OAEP.new(pub_key, hashAlgo=SHA256).encrypt)
cipher_bytes = encrypt(plain.to_bytes(32, byteorder='big'))
cipher = self.pack_byte_array(cipher_bytes,
self.params.cipher_chunk_size)
rnd_bytes = encrypt.locals['ros']
rnd = self.pack_byte_array(rnd_bytes, self.params.rnd_chunk_size)
return cipher, rnd