Fastest bitwise xor between two multibyte binary data variables

Question

What is the fastest way to implementat the following logic:

def xor(data, key):
    l = len(key)

    buff = \"\"
    for i in range(0, len(data)):
        b         


        

Answer 1

Following on my comment in the initial post, you can process large files rather quickly if you stick to numpy for key padding and bitwise XOR'ing, like so:

import numpy as np

# ...

def xor(key, data):

    data = np.fromstring(data, dtype=np.byte)
    key = np.fromstring(key, dtype=np.byte)

    # Pad the key to match the data length
    key = np.pad(key, (0, len(data) - len(key)), 'wrap')

    return np.bitwise_xor(key, data)