cocos2dx lua XXTEA来加密解密实现详解

cocos2dx lua已经集成了对lua脚本的加解密，见AppDelegate.cpp

1.     LuaStack* stack = engine->getLuaStack();
   
2.     stack->setXXTEAKeyAndSign("123", strlen("123"), "cloud", strlen("cloud"));

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它是通过XXTEA来加解密的。参数，key,keyLen,signment,signmentLen。它的签名作用可能是用来判断文件是否经过加密的。

       好，我们来对文件加密。打开cocos2d-x\external\xxtea文件夹，调用相关函数xxtea_encrypt进行加密，最后在文件开始位置，写上签名就可以了。我把相关操作封装成一个python文件。可以直接调用。

1. import xxteaModule
   
2. import os
   
3. 
   
4. def ReadFile(filePath):
   
5.     file_object = open(filePath,'rb')
   
6.     all_the_text = file_object.read()
   
7.     file_object.close()
   
8.     return all_the_text
   
9. 
   
10. def WriteFile(filePath,all_the_text):    
    
11.     file_object = open(filePath,'wb')    
    
12.     file_object.write(all_the_text)
    
13.     file_object.close()
    
14.     
    
15. def BakFile(filePath,all_the_text):
    
16.     file_bak = filePath[:len(filePath)-3] + 'bak'   
    
17.     WriteFile(file_bak,all_the_text)
    
18. 
    
19. 
    
20. 
    
21. def ListLua(path):
    
22.     fileList = [] 
    
23.     for root,dirs,files in os.walk(path):
    
24.        for eachfiles in files:
    
25.            if eachfiles[-4:] == '.lua' :               
    
26.                fileList.append(root + '/' + eachfiles)
    
27.     return fileList
    
28. 
    
29. def EncodeWithXxteaModule(filePath,key,signment):    
    
30.     all_the_text = ReadFile(filePath)    
    
31. 
    
32.     if all_the_text[:len(signment)] == signment :
    
33.         return
    
34.     #bak lua
    
35.     BakFile(filePath,all_the_text)
    
36.        
    
37.     encrypt = xxteaModule.encrypt(all_the_text,key)
    
38.     signment = signment + encrypt
    
39.     WriteFile(filePath,signment)    
    
40.     
    
41. def EncodeLua(projectPath,key,signment):
    
42.     path = projectPath + '/src'
    
43.     fileList = ListLua(path)
    
44.     for files in fileList:
    
45.         EncodeWithXxteaModule(files,key,signment)
    
46. 
    
47. def FixCpp(projectPath,key,signment):
    
48.     filePath = projectPath + '/frameworks/runtime-src/Classes/AppDelegate.cpp'
    
49.     all_the_text = ReadFile(filePath)
    
50. 
    
51.     #bak cpp
    
52.     BakFile(filePath,all_the_text)    
    
53. 
    
54. 
    
55.     pos = all_the_text.find('stack->setXXTEAKeyAndSign')
    
56.     left = all_the_text.find('(',pos)
    
57.     right = all_the_text.find(';',pos)   
    
58. 
    
59.     word = str.format('("%s", strlen("%s"), "%s", strlen("%s"))' % (key,key,signment,signment))
    
60.     
    
61.     all_the_text = all_the_text[:left] + word + all_the_text[right:-1]
    
62.     
    
63.     WriteFile(filePath,all_the_text) 
    
64.     
    
65.     
    
66.     
    
67. projectPath = "D:/cocosIDEWork/aseGame/"
    
68. key = "123"
    
69. signment = "cloud"
    
70. 
    
71. 
    
72. EncodeLua(projectPath,key,signment)
    
73. FixCpp(projectPath,key,signment)
    
74. print "encode ok"

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整个工程是用cocosIDE生成的。这个工具会自动加密src下的lua,并在AppDelegate.cpp中设置相应的密码与签名。xxTeaModule是对cocos2d-x\external\xxtea\xxtea.cpp的一个python封装。