from AES_128 import AES_128_CTR, random_data, XOR
from base64 import b64decode, b64encode
random_key = random_data(16)
def single_byte_xor_key(cipher): #returns the key
f = []
for i in xrange(0, 256):
f.append(0)
decrypted = ''
for c in cipher:
decrypted += chr(i ^ ord(c))
for c in decrypted:
if (
(ord(c) >= 65 and ord(c) <= 90)
or (ord(c) >= 97 and ord(c) <= 122) or ord(c) == 32
): #Calculating the no of alphabets in string decrypted with key i
f[i] += 1
max_f = 0
key = 0
for i in xrange(0, 256):
if (max_f < f[i]):
max_f = f[i]
key = i
return chr(key)
from random import randint
from base64 import b64decode,b64encode
from AES_128 import AES_128_CBC_decrypt,AES_128_CBC_encrypt,pkcs_7_unpad,XOR,random_data
IV = random_data(16)
def check_high_ASCII(data):
for c in data:
if ord(c) > 127 :
raise ValueError(data)
def encryption_oracle(data):
return AES_128_CBC_encrypt(data,IV)
def decryption_oracle(data):
txt = AES_128_CBC_decrypt(data,IV)
check_high_ASCII(txt)
return txt
def crack():
cipher = encryption_oracle('A'*80)
attack = cipher[0:16]+'\x00'*16+cipher[0:16]+cipher[-32:]
recovered_pt = ''
try:
recovered_pt = decryption_oracle(attack)
except ValueError as e:
recovered_pt = str(e)
key = XOR(recovered_pt[0:16],recovered_pt[32:48])
if key == IV :
print '[+] Cracked key : %s' % repr(key)
from AES_128 import AES_128_ECB_decrypt,AES_128_CTR,random_data,XOR
from base64 import b64decode
from random import randint
random_key = random_data(16)
def edit(ciphertext, offset, newtext):
pt = AES_128_CTR(txt, random_key)
pt = pt[:offset] + newtext + pt[offset+len(newtext):]
return AES_128_CTR(pt, random_key)
def crack(cipher, oracle):
attack = 'A'*len(cipher)
keystream = XOR (attack, oracle(cipher, 0, attack))
pt = XOR(cipher, keystream)
return pt
if __name__ == '__main__':
cipher = ''.join(line.strip() for line in open('25.txt','r'))
txt = AES_128_ECB_decrypt(b64decode(cipher), 'YELLOW SUBMARINE', True)
cipher = AES_128_CTR(txt, random_key)
newtext = random_data(randint(10,50))
offset = randint(0,len(cipher)-1)
if AES_128_CTR(edit(cipher, offset, newtext), random_key)[offset:offset+len(newtext)] == newtext :
print '[+] Edit Test passed'
else :
print '[-] Failed'