minor syntax cleanup

bschoening · bschoening · commit e3c2fa70a252 · 2021-10-27T17:42:55.000-04:00
diff --git a/README.md b/README.md
@@ -5,7 +5,7 @@
 
 # ff3 - Format Preserving Encryption in Python
 
-An implementation of the NIST approved Format Preserving Encryption (FPE) FF3 and FF3-1 algorithm in Python.
+An implementation of the NIST approved Format Preserving Encryption (FPE) FF3 and FF3-1 algorithms in Python.
 
 This package follows the FF3 algorithm for Format Preserving Encryption as described in the March 2016 NIST publication 800-38G _Methods for Format-Preserving Encryption_,
 and revised on February 28th, 2019 with a draft update for FF3-1.
diff --git a/ff3/ff3.py b/ff3/ff3.py
@@ -222,7 +222,7 @@ def encrypt_with_tweak(self, plaintext, tweak):
 
             # Tr is T[32..55] + T[28..31] + 0000
             Tr = bytearray(tweakBytes[HALF_TWEAK_LEN:])
-            Tr.append((tweakBytes[3]&0x0F)<<4)
+            Tr.append((tweakBytes[3] & 0x0F) << 4)
             print(f"Tweak:{tweakBytes.hex()} Tl:{Tl.hex()}, Tr:{Tr.hex()}")
         else:
             raise ValueError(f"tweak length {len(tweakBytes)} invalid: tweak must be 56 or 64 bits")
diff --git a/ff3/ff3_test.py b/ff3/ff3_test.py
@@ -310,6 +310,7 @@
     },
 ]
 
+
 class TestFF3(unittest.TestCase):
 
     def test_encode_int(self):
@@ -328,7 +329,6 @@ def test_decode_int(self):
         self.assertEqual(0x02, (decode_int_r("20", hexdigits)))
         self.assertEqual(0xAA, (decode_int_r("aa", hexdigits)))
 
-
     def test_aes_ecb(self):
         # NIST test vector for ECB-AES128
         key = bytes.fromhex('2b7e151628aed2a6abf7158809cf4f3c')
@@ -421,7 +421,7 @@ def test_custom_alphabet(self):
 
     # Check that encryption and decryption are inverses over whole domain
     def test_whole_domain(self):
-        TEST_CASES = [
+        test_cases = [
             # (radix, plaintext_len, alphabet (None means default))
             (2, 10, None),
             (3, 6, None),
@@ -431,15 +431,15 @@ def test_whole_domain(self):
             (3, 7, "ABC"),
         ]
 
-        max_radix = max(radix for radix, plaintext_len, alphabet in TEST_CASES)
+        max_radix = max(radix for radix, plaintext_len, alphabet in test_cases)
 
         # Temporarily reduce DOMAIN_MIN to make testing fast
         domain_min_orig = FF3Cipher.DOMAIN_MIN
         FF3Cipher.DOMAIN_MIN = max_radix + 1
 
         key = "EF4359D8D580AA4F7F036D6F04FC6A94"
         tweak = "D8E7920AFA330A73"
-        for radix, plaintext_len, alphabet in TEST_CASES:
+        for radix, plaintext_len, alphabet in test_cases:
             if alphabet is None:
                 c = FF3Cipher(key, tweak, radix=radix)
             else:
