cocos2d-x 图片资源加密,Lua文件加密 (转)
游戏开发中常遇到资源保护的问题。
目前游戏开发中常加密的文件类型有:图片,Lua文件,音频等文件,而其实加密也是一把双刃剑。
需要安全那就得耗费一定的资源去实现它。目前网上也有用TexturePacker工具来加密的,不过针对性还是不够强。
分析一下原理为:
1,转格式:将需要加密的文件转为流的方式;
2,加密:根据自己需要使用加密手段,MD5,AES,甚至可以直接改变位移,加一些自己的特殊字符也可以使文件简单加密,加密完后基本保证
图片类型基本用特殊软件预览不了也打不开,Lua文件加密后一片乱码····;
3,保存自定义格式文件:另存为自己特殊类型的文件名如"xx.d" "xx.xyz"等。
4,图片解密:修改cocos2dx底层库的获取路径处,和加载CCImage纹理处理时的源码修改;
5,特殊Lua文件界面:修改对应Lua加载方法;
基本原理清楚了后我贴几段我自己项目中常用的加密方式:
首先是转格式并且加密的方式
bool PublicCommen::recode_getFileByName(string pFileName){ unsigned long nSize = 0; unsigned char* pBuffer = CCFileUtils::sharedFileUtils()->getFileData( pFileName.c_str(), "rb",&nSize); unsigned char* newBuf = new unsigned char[nSize]; int newblen = nSize; if(pBuffer!=NULL&&nSize>0) { for (int i = 0; i<nSize; i++) { newBuf[i]=pBuffer[i]+MD5; } string savepath = pFileName; savepath = savepath.substr(0,savepath.length()-4); savepath = savepath + "xx.X"; FILE *fp = fopen(savepath.c_str(), "wb+"); fwrite(newBuf, 1, newblen, fp); fclose(fp); CCLOG("save file ok. path = %s" ,savepath.c_str()); return true; } return false; }
通常可以自己写一个应用程序遍历一下自定义目录下,需要转的资源文件,对应的把所有资源转换并加密;
里面newBuf[i]=pBuffer[i]+MD5;这段可以自由发挥!解密的时候需要对应!
当然你也可以取巧的放进你的游戏中修改cocos2dx底层的CCFileUtils::fullPathForFilename获取全路径的方法中;
下面说一下解密:
图片的解密需要修改cocos2dx CCTexture2D 的CCTextureCache::addImage类里面修改
CCTexture2D * CCTextureCache::addImage(const char * path) { CCAssert(path != NULL, "TextureCache: fileimage MUST not be NULL"); CCTexture2D * texture = NULL; CCImage* pImage = NULL; // Split up directory and filename // MUTEX: // Needed since addImageAsync calls this method from a different thread //pthread_mutex_lock(m_pDictLock); std::string pathKey = path; pathKey = CCFileUtils::sharedFileUtils()->fullPathForFilename(pathKey.c_str()); if (pathKey.size() == 0) { return NULL; } texture = (CCTexture2D*)m_pTextures->objectForKey(pathKey.c_str()); std::string fullpath = pathKey; // (CCFileUtils::sharedFileUtils()->fullPathFromRelativePath(path)); if (! texture) { std::string lowerCase(pathKey); for (unsigned int i = 0; i < lowerCase.length(); ++i) { lowerCase[i] = tolower(lowerCase[i]); } // all images are handled by UIImage except PVR extension that is handled by our own handler do { if (std::string::npos != lowerCase.find(".pvr")) { texture = this->addPVRImage(fullpath.c_str()); } else if (std::string::npos != lowerCase.find(".pkm")) { // ETC1 file format, only supportted on Android texture = this->addETCImage(fullpath.c_str()); } else { CCImage::EImageFormat eImageFormat = CCImage::kFmtUnKnown; if (std::string::npos != lowerCase.find(".png")) { eImageFormat = CCImage::kFmtPng; } else if (std::string::npos != lowerCase.find(".jpg") || std::string::npos != lowerCase.find(".jpeg")) { eImageFormat = CCImage::kFmtJpg; } else if (std::string::npos != lowerCase.find(".tif") || std::string::npos != lowerCase.find(".tiff")) { eImageFormat = CCImage::kFmtTiff; } else if (std::string::npos != lowerCase.find(".webp")) { eImageFormat = CCImage::kFmtWebp; } else if (std::string::npos != lowerCase.find("XX.X")) { eImageFormat = CCImage::xxxxx; } pImage = new CCImage(); CC_BREAK_IF(NULL == pImage); bool bRet = pImage->initWithImageFile(fullpath.c_str(), eImageFormat); CC_BREAK_IF(!bRet); texture = new CCTexture2D(); if( texture && texture->initWithImage(pImage) ) { #if CC_ENABLE_CACHE_TEXTURE_DATA // cache the texture file name VolatileTexture::addImageTexture(texture, fullpath.c_str(), eImageFormat); #endif m_pTextures->setObject(texture, pathKey.c_str()); texture->release(); } else { CCLOG("cocos2d: Couldn't create texture for file:%s in CCTextureCache", path); } } } while (0); } CC_SAFE_RELEASE(pImage); //pthread_mutex_unlock(m_pDictLock); return texture; }
并且在CCImage的图片类型中添加你加密后的图片类型如:CCImage::xxxxx
然后跟到 bool bRet = pImage->initWithImageFile(fullpath.c_str(), eImageFormat);
CCImage.mm中的CCImage::initWithImageFile方法;
bool CCImage::initWithImageFile(const char * strPath, EImageFormat eImgFmt/* = eFmtPng*/) { bool bRet = false; unsigned long nSize = 0; unsigned char* pBuffer = CCFileUtils::sharedFileUtils()->getFileData( CCFileUtils::sharedFileUtils()->fullPathForFilename(strPath).c_str(), "rb", &nSize); if(eImgFmt==xxxxxx) { for (int i= 0; i < nSize; i++) { pBuffer[i] = pBuffer[i]-MD5; } pBuffer[nSize] = pBuffer[nSize]-1; eImgFmt = kFmtPng; } if (pBuffer != NULL && nSize > 0) { bRet = initWithImageData(pBuffer, nSize, eImgFmt); } CC_SAFE_DELETE_ARRAY(pBuffer); return bRet; }
其中 pBuffer[i] = pBuffer[i]-MD5;需要和之前加密的时候对应·····自己发挥!
Ok,只要是图片,并且是属于你自定义类型的图片都会得到解密的真实texture。
Lua的解密也是基本一样的思路,不过解密需要单独在需要加载Lua的方法前先解密,要考虑跨平台性
http://www.cnblogs.com/zisou/p/3850593.html