hiding highscore text file in exe using py2exe/pygame2exe

问题

I have a highscore system in my game that I made in Pygame, it saves name and score in text files name.txt and score.txt but the problem is that anyone can edit that text files.So could i hide them in exe file.
python version 2.7
setup script: pygame2exe

And if it's possible could I do it without extra modules. UPDATE:I'll obviously need to encrypt text somehow.Can you suggest some simple encryption alghoritham? Note that I use numbers and newlines.

I would still want to put file in exe.

回答1:

There's not much point using strong encryption for this algorithm because your program needs to access the decryption key, so if a determined user looks at your program's code they can figure out where your program stores the key and what it does with it. True, reading & understanding the code in a .pyc is somewhat more difficult than reading a .py, but it's still a lot easier than breaking good encryption.

Anyway, here's some code that does simple encryption / decryption of an arbitrary string. It works best if the string isn't very random, and it works better on long strings than short ones.

To encrypt, it first compresses the data using gzip, which not only can make the data smaller, it reduces the amount of pattern in the data, which improves the quality of the encryption. It then XORs the integer value of each byte (in the zipped data) with a series of random integers in the range(256) to produce the encoded version.

The XOR operation is symmetrical in this sense: if a = b ^ c, then b = a ^ c (and also c = a ^ b). So to undo XORing, we just have to apply it again.

So to decrypt, we simply reverse the encryption process. First we XOR the encoded version with the same series of random integers we used to encode it and then we unzip it.

If the amount of data you want to hide is fairly small or highly random you can skip the zipping / unzipping steps, since XORing with a series of random bytes from a good pseudo-random number generator (like the Mersenne Twister that Python uses by default) is actually quite a good form of encryption, assuming that the attacker doesn't know both the algorithm that generates your random numbers and the seed for the random sequence. (Note that Python's random.seed() accepts any hashable object as the seed: eg an int, a string, or even a tuple).

The code below uses a calendar of the year as test data to make it easy to see that the process works.

gzipcrypt.py

#! /usr/bin/env python

''' Simple encryption
    Encode by gziping then XORing bytes with a pseudorandom stream
    Decode by XORing and then unziping with the same pseudorandom stream

    Written by PM 2Ring 2014.09.28
'''

import random

import sys
from calendar import calendar  


def randoms(seed):
    random.seed(seed)
    while True:
        yield random.randint(0, 255)


def xorcrypt(data, key):
    return str(bytearray(d ^ k for d, k in 
        zip(bytearray(data), randoms(key))))


def zipcrypt(data, key):
    return xorcrypt(data.encode('zlib_codec'), key)


def decryptzip(data, key):
    return xorcrypt(data, key).decode('zlib_codec')


def main():
    #Test encryption & decryption
    key = sys.argv[1] if len(sys.argv) > 1 else 42
    data = calendar(2014)

    print data
    print 'Length:', len(data), '\n'

    #code = xorcrypt(data, key)
    code = zipcrypt(data, key)
    print `code` 
    print 'Length:', len(code), '\n'

    #newd = xorcrypt(code, key)
    newd = decryptzip(code, key)
    print newd
    print newd == data


if __name__ == '__main__':
    main()

Edit

Here's a simpler version of xorcrypt() that doesn't use a generator function, bytearray(), or list comprehensions that's hopefully more comprehensible.

def xorcrypt1(data, key):
    random.seed(key)
    code = []
    for ch in data:
        n = ord(ch)
        n = n ^ random.randint(0, 255)
        code.append(chr(n))
    return ''.join(code)

来源：https://stackoverflow.com/questions/26078109/hiding-highscore-text-file-in-exe-using-py2exe-pygame2exe

标签

python

text

pygame

exe

py2exe