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challenge_6.py
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challenge_6.py
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#! /usr/bin/python3
import binascii
file = open("6.txt", 'r')
lines = binascii.a2b_base64(file.read())
ascii = list(range(ord('a'), ord('z') + 1)) +list(range(ord('A'), ord('Z') + 1)) +[ord(' ')]
# print(lines)
string1 = "this is a test"
string2 = "wokka wokka!!!"
# print(bytes(string1,""))
# print(sum([abs(ord(a)-ord(b)) for (a,b) in zip(string1, string2)]))
# print(string1.encode())
# int1 = int.from_bytes(string1.encode(),'big')
# int2 = int.from_bytes(string2.encode(),'big')
# print(bin(int1).count("1"))
# print(bin(int1^int2).count("1"))
def HammingDistance(string1, string2):
int1 = int.from_bytes(string1,'big')
int2 = int.from_bytes(string2,'big')
# print(bin(int1).count("1"))
return bin(int1^int2).count("1")
# line1 = Lines[0].strip()
# print(line1)
distances = []
for keysize in range(2,41):
# print(line1)
string1 = lines[0:keysize]
string2 = lines[keysize:2*keysize]
normalizedDistance = HammingDistance(string1, string2)/keysize
normalizedDistance2 = HammingDistance(lines[keysize*2:keysize*3], lines[keysize*3:keysize*4])/keysize
dist = (normalizedDistance + normalizedDistance2)/2
distances.append([dist, keysize])
# for keysize in range(len(distances)):
# print(distances[keysize])
distances.sort(key=lambda x :x[0])
for keysize in range(len(distances)):
print(distances[keysize])
blocks = []
for i in range(0, 6):
print("--------")
keysize = distances[i][1]
# print(keysize)
blocks.clear()
for key in range(keysize):
# print("key :" + str(key))
blocks.append([])
for lineIndex in range(len(lines)):
# print(lines[lineIndex])
blocks[lineIndex%keysize].append(lines[lineIndex])
# print(len(line)/keysize)
# for key in range(keysize):
# print(blocks[key])
fullKey = ""
for blockIndex in range(keysize):
input = blocks[blockIndex]
ratio = 0
key = 0
for letter in ascii:
# print(letter)
xor = bytes(letter ^ a for a in input)
trues = sum([x in ascii for x in xor])
if(trues/len(input) > ratio):
# print("here")
output = xor
ratio = trues/len(input)
key = letter
# print("\n")
# if(sum/len(xor) > ratio):
# ratio = sum/len(xor)
# result = xor
# print(output)
# print(chr(key))
fullKey += chr(key)
print(str(distances[i][1]) + " "+ fullKey)