cryptopals

commit 7a4dd4bb0dbcda24943c6c6f4a55f37863706a67
parent ec1908d607e1536e792fdc710cca740a5cfbb21a
Author: mpizzzle <michael.770211@gmail.com>
Date:   Sun,  5 Nov 2017 21:54:50 +0000

minor refactoring

Diffstat:
M
set3/break_fixed_nonce_ctr_statistically.py
 | 
9
++++-----
M
set3/break_fixed_nonce_ctr_using_substitutions.py
 | 
3
+--

2 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/set3/break_fixed_nonce_ctr_statistically.py b/set3/break_fixed_nonce_ctr_statistically.py
@@ -8,6 +8,9 @@ key = Random.new().read(AES.block_size)
 def encrypt(plaintext):
     return AES.new(key, AES.MODE_CTR, counter=Counter.new(128)).encrypt(plaintext)
 
+def decrypt(key, msg):
+    return ''.join([chr(ord(key[i % len(key)]) ^ ord(char)) for i, char in enumerate(msg)])
+
 def get_candidate_key_byte(transposed_block):
     candidate = ''
     candidate_frequency = 0
@@ -22,9 +25,6 @@ def get_candidate_key_byte(transposed_block):
 
     return candidate
 
-def decrypt(key, msg):
-    return ''.join([chr(ord(key[i % len(key)]) ^ ord(char)) for i, char in enumerate(msg)])
-
 def get_key(file, key_length):
     split_file = [file[i:i + key_length] for i in range(0, len(file), key_length)]
     transposed_blocks = [''.join([block[x] for block in split_file[:len(split_file) - 1]]) for x in range(key_length)]
@@ -35,8 +35,7 @@ with open('files/20.txt') as f:
 
 key_length = min(len(ct) for ct in ciphertexts)
 ciphertext = ''.join([ct[:key_length] for ct in ciphertexts])
-found_key = get_key(ciphertext, key_length)
-plaintext = decrypt(found_key, ciphertext)
+plaintext = decrypt(get_key(ciphertext, key_length), ciphertext)
 
 for line in [plaintext[i:i + key_length] for i in range(0, len(plaintext), key_length)]:
     print line
diff --git a/set3/break_fixed_nonce_ctr_using_substitutions.py b/set3/break_fixed_nonce_ctr_using_substitutions.py
@@ -24,6 +24,5 @@ def drag_crib(crib, a_xor_b):
     print derp
 
 for i in range(40):
-    if i != 5:
         print i
-        drag_crib("r polite ", xor(ciphertexts[i], ciphertexts[5]))
+        drag_crib("or polite meaningless ", xor(ciphertexts[i], ciphertexts[5]))