XOR between Python and C++

Question

I have scripted a Python script (Python v3.9) to give me the little endian output of a XOR encrypted string. And then I tried to write a C++ program that will decode those bytes by using the same XOR key. My Python script follows.

import itertools

stringMessage = "TEST STRING !@#"
xorKey = "Hello324234523"

def xor(message, key):
    toret = ''
    for c, k in zip(message, itertools.cycle(key)):
        toret += chr(ord(c) ^ ord(k))
    return toret

encrypted = xor(stringMessage, xorKey)

print("".join("\\x{:02x}".format(ord(c)) for c in encrypted))

The final result is \x1c\x20\x3f\x38\x4f\x60\x66\x66\x7b\x7d\x73\x15\x13\x73\x6b, which is then copied manually in to the C++ source like so..

    char encryptedMessage[] = "\x1c\x20\x3f\x38\x4f\x60\x66\x66\x7b\x7d\x73\x15\x13\x73\x6b";
    char xorKey[] = "Hello324234523";
    char decryptedMessage[sizeof encryptedMessage];
    int j = 0;
    for (int i = 0; i < sizeof encryptedMessage; i++) {
        if (j == sizeof xorKey - 1) j = 0;
        decryptedMessage[i] = encryptedMessage[i] ^ xorKey[j];
        j++;
    }
    printf("-------------------------\n");
    printf(decryptedMessage);

But when I compile and execute my C++ program, instead of getting TEST STRING !@# as a result, I get TEST STRING !@#e∟ ?8O`ff{}s§‼sk. I don't understand what the extra e∟ ?8O`ff{}s§‼sk string is.

Answer 1

Changed for (int i = 0; i < sizeof shellcode; i++) { to for (int i = 0; i < sizeof shellcode - 1; i++) { and it now works!