commit 285909bbc8dce85c3d926410f8fb146fbed884f9
parent 6a39e1608e35c57d68d9edc8ea6eef7bdd711a10
Author: mpizzzle <michael.770211@gmail.com>
Date: Sat, 7 Oct 2017 15:58:42 +0100
more refactoring
Diffstat:
1 file changed, 8 insertions(+), 10 deletions(-)
diff --git a/set1/break_repeating_key_xor.py b/set1/break_repeating_key_xor.py
@@ -12,6 +12,7 @@ def get_candidate_key_length(file, accuracy):
for key_length in range(2, 40):
this_distance = sum([distance(file[key_length * x:key_length * (x + 1)], file[key_length * (x + 1):key_length * (x + 2)]) for x in range(accuracy)])
average_distance = this_distance / float(key_length * (accuracy))
+
if average_distance < candidate_distance:
candidate_distance = average_distance
candidate_length = key_length
@@ -22,17 +23,14 @@ def get_candidate_key_byte(transposed_block):
candidate = ''
candidate_frequency = 0
- for x in range(128):
- frequency = 0
- plaintext = ''.join([chr(x ^ ord(a)) for a in transposed_block])
-
- for char in plaintext:
- if char in frequent_letters:
- frequency += 1
+ for c in range(128):
+ plaintext = ''.join([chr(c ^ ord(a)) for a in transposed_block])
+ frequency = sum([plaintext.count(frequent_letters[n]) for n in range(len(frequent_letters))])
if frequency > candidate_frequency:
- candidate = chr(x)
+ candidate = chr(c)
candidate_frequency = frequency
+
return candidate
def decrypt(key, msg):
@@ -43,8 +41,8 @@ with open('files/6.txt') as f:
key_length = get_candidate_key_length(file, 10)
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)]
-key = ''.join([get_candidate_key_byte(transposed_block) for transposed_block in transposed_blocks])
+transposed_blocks = [''.join([block[x] for block in split_file[:len(split_file) - 1]]) for x in range(key_length)]
+key = ''.join([get_candidate_key_byte(block) for block in transposed_blocks])
print key
print decrypt(key, file)
\ No newline at end of file
