Question

Could you please help me converting this c++ code into python:
I am trying to XOR the data

C++ :

void Encrypt(void data, Dword size)
{
    if(size > 0)
        for(DWORD i = size - 1; i > 0; i--)
            ((LPBYTE)data)[i] ^= ((LPBYTE)data)[i - 1];
}

Answer 1

To do this in python, you probably want to use the bytearray class:

def encrypt(data):
    n = len(data)
    for i in range(n-1, 0, -1):
        data[i] ^= data[i-1]      # for this to work, data has to be mutable

f = open('somefile.bin', 'rb')
buf = bytearray(f.read())
f.close()

encrypt(buf)

Note the comment, that you cannot pass a string object, because strings in python are immutable. bytearray on the other hand, is not.