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test attack

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This commit is contained in:
Sam Hadow 2024-04-22 19:39:22 +02:00
parent 0c0ff62e1f
commit 7a1bf3b06a
1 changed files with 19 additions and 18 deletions
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37
main.py
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@ -93,25 +93,16 @@ def test_encrypt():
print(f'decrypted: {hex(clear)}')
print(f'original text and decrypted message are the same: {clear==0xffffffffff}')
def gen_6_bytes():
key = [randint(0, 1) for _ in range(40)]
# key = [1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0]
# key = [0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1]
def gen_6_bytes(key=[randint(0, 1) for _ in range(40)]):
text = b'\x00\x00\x00\x00\x00\x00'
print(key)
cipher = css_encrypt(text, key)
print(cipher)
print(css_encrypt(cipher, key))
return cipher
def attack():
Bytes = gen_6_bytes()
def attack(Bytes=gen_6_bytes()):
taps17 = [0, 14]
taps25 = [0, 3, 4, 12]
# (2**16)-1
for i in range((2**16)-1):
lfsr17_init = [int(bit) for bit in bin(i)[2:].zfill(16)]+[1]
# print(lfsr17_init)
lfsr17 = lfsr(lfsr17_init, taps17)
x = []
for _ in range(3):
@ -125,11 +116,6 @@ def attack():
c=1 if x[1]+y[1]>255 else 0
y.append((Bytes[2]-(x[2]+c))%256)
lfsr25_init = [int(bit) for bit in (bin(y[0])[2:].zfill(8)[::-1] + bin(y[1])[2:].zfill(8)[::-1] + bin(y[2])[2:].zfill(8)[::-1] ) ]+[1]
# print(f'x: {x}, y: {y}')
# for b in Bytes:
# print(b, end=' ')
# print('\n')
# print(lfsr25_init)
lfsr25 = lfsr(lfsr25_init, taps25)
for _ in range(24):
lfsr25.shift()
@ -148,15 +134,30 @@ def attack():
c=1 if x[4]+y[4]>255 else 0
z6 = (x[5]+y[5]+c)%256
if z4 == Bytes[3] and z5 == Bytes[4] and z6 == Bytes[5]:
print("key found:")
print("key found: ", end='\t')
key = bin(x[0])[2:].zfill(8)[::-1] + bin(x[1])[2:].zfill(8)[::-1] + bin(y[0])[2:].zfill(8)[::-1] + bin(y[1])[2:].zfill(8)[::-1] + bin(y[2])[2:].zfill(8)[::-1]
print(key)
return [int(bit) for bit in key]
break
def test_attack(n=1):
success = 0
print(f'testing attack in 2^16 against CSS {n} times (keys randomly generated each time)\n')
for _ in range(n):
key = [randint(0, 1) for _ in range(40)]
key_string = ''.join(str(bit) for bit in key)
print(f'key generated: \t{key_string}')
Bytes = gen_6_bytes(key)
found_key = attack(Bytes)
if found_key == key:
success += 1
print()
print(f'{success}/{n} success')
test_lfsr17()
print()
test_encrypt()
print()
#gen_6_bytes()
attack()
test_attack(100)