I am trying to solve a problem where I have to decrypt a file. But I found an obstacle. As you can see in the below code, I need to do a bitwise xor between key and number 47.
from Crypto.Cipher import AES
import base64
l1 = open("./2015_03_13_mohamed.said.benmousa.puerta_trasera.enc", "rb");
iv = l1.read(16)
enc = l1.read()
l1.close()
#key = xor beetwen kiv(47) and IV
key = iv
for i in range(len(key)):
key[i] = key[i] ^ 47
obj = AES.new(key,AES.MODE_CBC, iv)
obj1 = obj.decrypt(enc)
l = open("./ej3.html", "wb").write(obj1)
When I try that I get the following error:
TypeError: unsupported operand type(s) for ^: 'str' and 'int'
I searched things here but I can't get it. Thank you.
because you need an int
ascii_code_for_a = ord('a') == 97 #convert a character to an ascii integer
int2chr = chr(97) == 'a' #convert an ascii code back to a character
so just do
key = list(iv) # first convert it to a list ... strings are unmutable
for i in range(len(key)):
key[i] = chr(ord(key[i]) ^ 47)