fixed some lint errors

kyber/ccakem.py

@@ -1,5 +1,5 @@
 from secrets import token_bytes
-from kyber.encryption import generate_keys, Encrypt, Decrypt
+from kyber.encryption import generate_keys, Encrypt, decrypt
 from kyber.utils.pseudo_random import H, G, kdf
 from kyber.constants import k, n, du, dv
 
@@ -56,7 +56,7 @@ def ccakem_decrypt(ciphertext: bytes, private_key: bytes, shared_secret_length:
 
  assert h == H(pk)
 
- m = Decrypt(sk, ciphertext).decrypt()
+ m = decrypt(sk, ciphertext)
  Kr = G(m + h)
  K, r = Kr[:32], Kr[32:]
  c = Encrypt(pk, m, r).encrypt()

kyber/encryption/__init__.py

@@ -1,3 +1,3 @@
 from kyber.encryption.keygen import generate_keys
 from kyber.encryption.encrypt import Encrypt
-from kyber.encryption.decrypt import Decrypt
+from kyber.encryption.decrypt import decrypt

kyber/encryption/decrypt.py

@@ -4,33 +4,29 @@
 from kyber.constants import n, k, du, dv
 from kyber.entities.polring import PolynomialRing
 
-class Decrypt:
- def __init__(self, private_key, ciphertext) -> None:
- self._sk = private_key
- self._c = ciphertext
- if len(self._sk) != 32*12*k:
- raise ValueError()
- if len(self._c) != du*k*n//8 + dv*n//8:
- raise ValueError()
+def decrypt(private_key, ciphertext) -> bytes:
+ """
+ Decrypts the given ciphertext with the given private key.
+ :returns Decrypted 32-bit shared secret
+ """
 
- def decrypt(self) -> bytes:
- """
- Decrypts the given ciphertext with the given private key.
- :returns Decrypted 32-bit shared secret
- """
+ if len(private_key) != 32*12*k:
+ raise ValueError()
+ if len(ciphertext) != du*k*n//8 + dv*n//8:
+ raise ValueError()
 
-  s = np.array(decode(self._sk, 12))
+ s = np.array(decode(private_key, 12))
 
-  u, v = self._c[:du*k*n//8], self._c[du*k*n//8:]
+ u, v = ciphertext[:du*k*n//8], ciphertext[du*k*n//8:]
 
-  u = decode(u, du)
-  v = decode(v, dv)[0]
+ u = decode(u, du)
+ v = decode(v, dv)[0]
 
-  u = np.array([decompress(pol, du) for pol in u])
-  v = decompress(v, dv)
+ u = np.array([decompress(pol, du) for pol in u])
+ v = decompress(v, dv)
 
-  m: PolynomialRing = v - np.matmul(s.T, u)
-  m: bytes = encode(compress([m], 1), 1)
+ m: PolynomialRing = v - np.matmul(s.T, u)
+ m: bytes = encode(compress([m], 1), 1)
 
-  assert len(m) == 32
-  return m
+ assert len(m) == 32
+ return m

tests/test_cbd.py

@@ -1,5 +1,5 @@
 import unittest
-from random import seed,randbytes
+from random import seed, randbytes
 from base64 import b64decode
 from kyber.utils.cbd import cbd
 

tests/test_decrypt.py

@@ -1,6 +1,6 @@
 import unittest
 from random import seed, randbytes
-from kyber.encryption import Decrypt
+from kyber.encryption import decrypt
 from kyber.constants import k, n, du, dv
 
 class TestDecrypt(unittest.TestCase):
@@ -10,7 +10,7 @@ def setUp(self):
  def test_decryption_outputs_valid_shared_secret(self):
  private_key = randbytes(32*12*k)
  ciphertext = randbytes(du*k*n//8 + dv*n//8)
- shared_secret = Decrypt(private_key, ciphertext).decrypt()
+ shared_secret = decrypt(private_key, ciphertext)
  self.assertEqual(type(shared_secret), bytes)
  self.assertEqual(len(shared_secret), 32)
 
@@ -19,11 +19,11 @@ def test_decryption_raises_with_invalid_private_key(self):
  invalid_private_key = randbytes(32*12*k + 1)
  valid_ciphertext = randbytes(du*k*n//8 + dv*n//8)
  with self.assertRaises(ValueError):
- Decrypt(invalid_private_key, valid_ciphertext)
+ decrypt(invalid_private_key, valid_ciphertext)
 
  def test_decryption_raises_with_invalid_ciphertext(self):
  # this ciphertext is one byte too short
  valid_private_key = randbytes(32*12*k)
  invalid_ciphertext = randbytes(du*k*n//8 + dv*n//8 - 1)
  with self.assertRaises(ValueError):
- Decrypt(valid_private_key, invalid_ciphertext)
+ decrypt(valid_private_key, invalid_ciphertext)

tests/test_encryption.py

@@ -1,12 +1,12 @@
 import unittest
-from kyber.encryption import generate_keys, Encrypt, Decrypt
+from kyber.encryption import generate_keys, Encrypt, decrypt
 
 class TestIntegration(unittest.TestCase):
  def test_encryption_symmetry(self):
  # test the whole process of key generation, encryption and decryption
  private_key, public_key = generate_keys()
  encrypter = Encrypt(public_key)
  ciphertext = encrypter.encrypt()
- decrypted_shared_secret = Decrypt(private_key, ciphertext).decrypt()
+ decrypted_shared_secret = decrypt(private_key, ciphertext)
  self.assertEqual(encrypter.secret, decrypted_shared_secret)
  self.assertEqual(len(encrypter.secret), 32)