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working automated weaponized first preimage attack

This commit is contained in:
Christoph J. Scherr 2023-04-22 10:20:13 +02:00
parent 3cd27dab04
commit c3f71b9596
Signed by: PlexSheep
GPG Key ID: 25B4ACF7D88186CC
2 changed files with 12 additions and 7 deletions
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1
src/calchash.py Normal file → Executable file
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@ -1,3 +1,4 @@
#!/usr/bin/env python3
# this is literal garbage
# does not even work for the bad hash
def calcHash():

18
src/trash-hash.py Normal file → Executable file
View File

@ -8,7 +8,8 @@ import random
DEFINED_INITIAL = bytearray(b'\xa5\xa5\xa5\xa5\x5a\x5a\x5a\x5a\x55\x55\x55\x55\xaa\xaa\xaa\xaa')
# the hash we want to find in the preimage attacks
# comes from 'AAAA'
THE_HASH = bytearray(b'\xe4\xe4\xe4\xe4\xa5\xa5\xa5\xa5\xaa\xaa\xaa\xaa\x55\x55\x55\x55')
#THE_HASH = bytearray(b'\xe4\xe4\xe4\xe4\xa5\xa5\xa5\xa5\xaa\xaa\xaa\xaa\x55\x55\x55\x55')
THE_HASH = bytearray(b'\xa4\xf4\xea\xee\xa5\xa5\xa5\xa5\xaa\xaa\xaa\xaa\x55\x55\x55\x55')
def trash_hash(input: bytearray) -> bytearray:
#print("original len is %s" % len(input))
@ -59,6 +60,8 @@ def test_collision(a: bytearray, b: bytearray) -> bool:
return trash_hash(a) == trash_hash(b)
def test_against_hash(input: bytearray, target_hash: bytearray) -> bool:
print("given input:\t%s" % input.hex())
print("given input (repr):\t%s" % input.decode(errors="ignore"))
hashed = trash_hash(input)
print("hashed variant:\t%s" % hashed.hex())
print("should be:\t%s" % THE_HASH.hex())
@ -75,13 +78,14 @@ def first_preimage():
for i in range(0, 16):
between[i] = target[i] ^ DEFINED_INITIAL[i]
print("%d:\tbtw %s\ttar %s\thash %s" % (i, between.hex(), target.hex(), THE_HASH.hex()))
input[i] = between[i] ^ THE_HASH[i]
print("%d:\tbtw %s\ttar %s\thash %s" % (i, between.hex(), target.hex(), THE_HASH.hex()))
assert THE_HASH[i] == input[i] ^ target[i], "xor circle is broken"
between[i] = THE_HASH[i] ^ DEFINED_INITIAL[i]
print("%d:\tbtw %s\ttar %s\thash %s\n\tini %s\tinp %s" % (i, between.hex(), target.hex(), THE_HASH.hex(), DEFINED_INITIAL.hex(), input.hex()))
input[i] = target[i] ^ between[i]
print("%d:\tbtw %s\ttar %s\thash %s\n\tini %s\tinp %s" % (i, between.hex(), target.hex(), THE_HASH.hex(), DEFINED_INITIAL.hex(), input.hex()))
assert THE_HASH[i] == DEFINED_INITIAL[i] ^ between[i], "xor circle is broken: %s vs %s" % (hex(THE_HASH[i]), hex(input[i] ^ between[i]))
print(test_against_hash(input, THE_HASH))
input: bytearray = bytearray(bytes(a ^ b for a, b in zip(input, target)))
print("for input '%s':\n %s" % (input, test_against_hash(input, THE_HASH)))
def main():
first_preimage()