moved basic-decrypt.py to this repo
This commit is contained in:
parent
cd55bd1021
commit
3cd27dab04
|
@ -0,0 +1,122 @@
|
|||
#!/usr/bin/env python3
|
||||
|
||||
MAX_IN_LINE = 16
|
||||
DE_MOST_COMMON = ['E', 'N', 'I', 'R', 'A']
|
||||
EN_MOST_COMMON = ['E', 'T', 'A', 'O', 'I']
|
||||
|
||||
def main():
|
||||
with open("chiffrat.txt", "r") as file:
|
||||
text = file.read().split(" ")
|
||||
intarr = []
|
||||
chars_in_text: int = len(text)
|
||||
for item in text:
|
||||
intarr.append(int(item, 16))
|
||||
print('=' * 80)
|
||||
print("dumping cyphertext (%d chars)" % chars_in_text)
|
||||
print('=' * 80)
|
||||
print(dump_intarr(intarr))
|
||||
freq = freq_analysis(intarr)
|
||||
print('=' * 80)
|
||||
print("Top 5 occurences:")
|
||||
print('=' * 80)
|
||||
dump_frequencies(freq, chars_in_text)
|
||||
print('=' * 80)
|
||||
print("Trying to find key from frequencies")
|
||||
print('=' * 80)
|
||||
key = find_key(freq, DE_MOST_COMMON)
|
||||
if not key:
|
||||
print("The key could not be determined.")
|
||||
if key:
|
||||
print('=' * 80)
|
||||
print("decrypt (key %d):" % key)
|
||||
print('=' * 80)
|
||||
decry = shift_intarr(intarr, key)
|
||||
print(dump_intarr(decry))
|
||||
|
||||
def freq_analysis(intarr: list):
|
||||
freql: dict = {}
|
||||
for i in range(0, 255):
|
||||
freql[i] = 0
|
||||
# list of tuples with all possible values and their frequency
|
||||
for item in intarr:
|
||||
freql[item] += 1
|
||||
return dict(sorted(freql.items(), key=lambda item: item[1], reverse=True))
|
||||
|
||||
def find_key(freq: dict, language_reference: list):
|
||||
# caesar
|
||||
caesar_keys = [0] * len(language_reference)
|
||||
for index, common_char in enumerate(language_reference):
|
||||
# this is probably garbage
|
||||
caesar_keys[index] = list(freq.values())[index] - ord(common_char) - 64
|
||||
|
||||
all_same = False
|
||||
for i in range(1, len(caesar_keys)):
|
||||
if all_same:
|
||||
all_same = caesar_keys[i-1] == caesar_keys[i]
|
||||
else: break
|
||||
if all_same:
|
||||
print("found a perfect match in the caesar checks: %s" % caesar_keys)
|
||||
return caesar_keys[0]
|
||||
else:
|
||||
print("Caesar keys ambiguos: %s" % caesar_keys)
|
||||
# was not caesar encrypted, continue with XOR checks
|
||||
# XOR
|
||||
xor_keys = [0] * len(language_reference)
|
||||
for index, common_char in enumerate(language_reference):
|
||||
# this is probably garbage
|
||||
item = list(freq.values())[index]
|
||||
xor_keys[index] = item ^ ord(common_char)
|
||||
|
||||
all_same = False
|
||||
for i in range(1, len(xor_keys)):
|
||||
if all_same:
|
||||
all_same = xor_keys[i-1] == xor_keys[i]
|
||||
else: break
|
||||
if all_same:
|
||||
print("found a perfect match in the caesar checks: %s" % xor_keys)
|
||||
return xor_keys[0]
|
||||
else:
|
||||
# ????????
|
||||
print("xor keys ambiguos: %s" % xor_keys)
|
||||
|
||||
|
||||
def dump_frequencies(frequencies, chars_in_text: int = -1, print_top_x = 5):
|
||||
for i in range(print_top_x):
|
||||
print("Top %s:\t'%s' with %s\toccurences (%s%%)" % (
|
||||
i+1,
|
||||
hex(list(frequencies.keys())[i]),
|
||||
list(frequencies.values())[i],
|
||||
(list(frequencies.values())[i] / chars_in_text) * 100,
|
||||
))
|
||||
|
||||
def shift_intarr(cypher_text_arr, key: int = 0):
|
||||
decrypt = [0] * len(cypher_text_arr)
|
||||
for index, item in enumerate(cypher_text_arr):
|
||||
decrypt[index] = item + key
|
||||
return decrypt
|
||||
|
||||
def dump_intarr(intarr) -> str:
|
||||
output = ""
|
||||
for index, item in enumerate(intarr) :
|
||||
if index % MAX_IN_LINE == 0:
|
||||
output += ("%02x\t| %02x " % (index,item))
|
||||
elif index % MAX_IN_LINE == MAX_IN_LINE - 1:
|
||||
output += ("%02x\n" %item)
|
||||
else:
|
||||
output += ("%02x " %item)
|
||||
# now dump as chars
|
||||
output += ("\n" + '=' * 80 + "\n")
|
||||
output += ("Char Representation\n")
|
||||
output += ('=' * 80 + "\n")
|
||||
char_max = MAX_IN_LINE * 4
|
||||
for index, item in enumerate(intarr) :
|
||||
if index % char_max == 0:
|
||||
output += ("%s\t| %c " % (hex(index),item))
|
||||
elif index % char_max == char_max - 1:
|
||||
output += ("%c\n" %item)
|
||||
else:
|
||||
output += ("%c " %item)
|
||||
return output
|
||||
|
||||
if __name__ == "__main__":
|
||||
main()
|
Loading…
Reference in New Issue