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update readme

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aaron
2021-12-04 04:48:22 +01:00
parent 5d93a845ce
commit e8e8d7c865
1 changed files with 2 additions and 2 deletions
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crypto/XMASSpirit/README.md
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@@ -24,7 +24,7 @@ HTB{4ff1n3_c1ph3r_15_51mpl3_m47h5}
- So it's possible to attack the encryption by iterating and trying to create a pair (a, b) that matches the entire encrypted pdf header. - So it's possible to attack the encryption by iterating and trying to create a pair (a, b) that matches the entire encrypted pdf header.
```python ```python
def get_factors(ct, n=256): def get_factors(ct:bytes, n:int=256) -> (int, int):
''' find a and b for n and ct ''' ''' find a and b for n and ct '''
# first generate a list of all numbers without common divisor with 256 # first generate a list of all numbers without common divisor with 256
nogcds = [ x for x in range(1, n) if gcd(x, n) == 1 ] nogcds = [ x for x in range(1, n) if gcd(x, n) == 1 ]
@@ -43,7 +43,7 @@ def get_factors(ct, n=256):
- When the factors are found, simply create a lookup table of all values and substitute each byte in the ciphertext. - When the factors are found, simply create a lookup table of all values and substitute each byte in the ciphertext.
```python ```python
def decrypt(ct): def decrypt(ct:bytes) -> bytes:
''' decrypt the file using the lookup table ''' ''' decrypt the file using the lookup table '''
res = b'' res = b''
for byte in ct: for byte in ct: