AzDG可逆加密演算法 for Python

花了二天的時間將AzDG可逆加密演算法改寫成Python
只在Python 2.6版上測試........
另外，針對台灣環境，
進行解密時，若數據源為Big5編碼的字串，會再轉成utf-8的編碼以便正常顯示中文。

#! /usr/bin/python
# -*- coding: utf-8 -*-
# python 2.6

import hashlib
import sys
import base64
import time


default_encoding = 'utf-8'
if sys.getdefaultencoding() != default_encoding:
    reload(sys)
    sys.setdefaultencoding(default_encoding)

class AzDG:
    """docstring for AzDG"""

    cipher = '0123456789'
    charset = 'utf-8'
    
    def __init__(self, cipher = None):
        if cipher != None:
            self.cipher = cipher

    def getCipher(self):
        return self.cipher

    def cipherEncode(self, sourceText):    
        cipherHash = hashlib.md5(self.getCipher()).hexdigest()
        cipherEncodeText = ''
        for i in range(len(sourceText)):            
            cipherEncodeText = '%s%s' % (cipherEncodeText, chr(ord(sourceText[i]) ^ ord(cipherHash[i%32])))    
        print len(cipherEncodeText)    
        return cipherEncodeText

    def encode(self, sourceText, charset = 'utf-8'):
        if charset != self.charset:
            sourceText = sourceText.encode(charset)
        #noise = hashlib.md5('%s' % (time.time())).hexdigest()
        noise = hashlib.md5('%s' % 1).hexdigest()
        encodeText = ''
        for i in range(len(sourceText)):
            encodeText = '%s%s%s' % (encodeText, noise[i%32], chr(ord(sourceText[i]) ^ ord(noise[i%32])))
        return base64.b64encode(self.cipherEncode(encodeText))
    
    def decode(self, sourceText, charset = 'utf-8'):
        decodeSourceText = self.cipherEncode(base64.b64decode(sourceText))
        textLength = len(decodeSourceText)
        decodeText = ''
        i = 0
        while i < textLength:
            decodeText = '{0}{1}'.format(decodeText, chr(ord(decodeSourceText[i]) ^ ord(decodeSourceText[i+1])))
            i = i + 2
        if self.charset != charset:
            decodeText =  unicode(decodeText, charset).encode(self.charset)
        return decodeText   

#utf-8編碼
azdg = AzDG()
m = azdg.encode('中文測試')
print azdg.decode(m)

#big5編碼，下列字串解開後的值︰大5編碼許功蓋中文測試字
print azdg.decode('A6hTbQVgV+wMLlXnVVoOvV0PD/FaCAbqDw8HogLyAfEF7wXlA6lX6VbSVP1Wcw==','big5')