cocoscreator 资源加密

当我们做完一个游戏以后，需要对自己图片资源做一定的加密保护，不让别人轻易的破解。cocos官方没有提供资源加密功能，下面提供一种交简单的加解密方案。

一、生成加密脚本

加密脚本:encode.py(这个脚本会生成加密后的图片替换原始图片)

# -*- coding:UTF-8 -*-
#该脚本用于加密png图片 使用python3以上版本解释执行
__author__ = "ChenGuanzhou"import os
import time
CUR_DIR = os.getcwd() + "\\build\\jsb-link\\assets"  # 编译后资源所在的目录，这里是link模式。
print("cur_dir:",CUR_DIR)
_KEY = "xxxxxxxx"                #指定加密秘钥,英文
_ENCRYSIG = 'jiaozhi'            #添加于文件开头用于判断是否是加密文件
_PNGSIG = bytes([0x89,0x50,0x4e,0x47,0x0d,0x0a,0x1a,0x0a])
_PNGIEND = bytes([0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4E, 0x44, 0xAE, 0x42, 0x60, 0x82])#获取filesig是否是png
def isPNGSig(bytes_8):return bytes_8 == _PNGSIGdef isPNG(absPath):#判断是否是PNG图片""":param absPath: 文件的绝对路径:return: {Bool}"""isFile = os.path.isfile(absPath)hasPNGSig = FalsefileExt = os.path.splitext(absPath)[1]isPngExt = (fileExt == ".png" or fileExt == ".PNG")if isFile and isPngExt:with open(absPath,"rb") as file:hasPNGSig = isPNGSig(file.read(8)[:8])return isFile and isPngExt and hasPNGSigdef preProcessPng(pngData):#预处理图片数据"""剪掉png的signature(8bytes),IEND(12Bytes):param pngData::return:"""assert type(pngData) == byteslostHeadData = pngData[8:]iendData = lostHeadData[-12:]if iendData == _PNGIEND:#防止Png已经进行过外部软件的压缩,丢掉了IENDreturn lostHeadData[:-12]else:return lostHeadDatadef encryption(fileData,key):#加密操作 ascii占一个字节"""加密png数据:param fileData:{bytes}预处理后的png数据:param key:{str}秘钥:return:{bytes}加密后的数据"""assert type(key) is strk = bytes(key,"utf8")klen= len(k)kindex = 0fileData = bytearray(fileData)for i,v in enumerate(fileData):if kindex >= klen:kindex = 0fileData[i] = v ^ k[kindex]#加密kindex = kindex + 1return bytes(_ENCRYSIG,"utf8") + fileData#处理图片
def processPNG(filePath):global filenumfileData = Nonewith open(filePath,'rb') as file:fileData = encryption(preProcessPng(file.read()),_KEY)os.remove(filePath)with open(filePath,'wb') as file: #覆盖新文件file.write(fileData)filenum = filenum + 1def traverseDir(absDir):#遍历当前目录以及递归的子目录，找到所有的png图片""":param absDir: 要遍历的路径:return: None"""assert (os.path.isdir(absDir) and os.path.isabs(absDir))dirName = absDirfor fileName in os.listdir(absDir):absFileName = os.path.join(dirName,fileName)print("isPNG:",absFileName)if os.path.isdir(absFileName):#递归查找文件夹print("absFileName:",absFileName)traverseDir(absFileName)elif isPNG(absFileName):print("isPNG:",absFileName)processPNG(absFileName)else:pass#------------------- 主函数-------------------------#
start_clock = time.clock()
filenum = 0
traverseDir(CUR_DIR)
end_clock = time.clock()
time = (end_clock - start_clock)*1000
print("encrypt %d Png Pictures"%filenum)
print("use time %fms"%time)

接下来做成一个批处理文件： encode.bat

python jm.py
pause

把encode.py 和 encode.bat 一起放到项目根目录下。

二、修改引擎c代码

这里以cocosDashboard 中 creator2.4.3为例。
修改的代码文件位置：
CocosDashboard\resources.editors\Creator\2.4.3\resources\cocos2d-x\cocos\platform中的CCImage.h和CCImage.c

CCImage.h添加：

1、Format 增加文件类型：

/** Supported formats for Image */enum class Format{//! JPEGJPG,//! PNGPNG,//! ENCRYPTEDPNG，下面这行是新加的ENCRYPTEDPNG, //加密后的Png图片//! TIFFTIFF,//! WebPWEBP,//! PVRPVR,//! ETCETC,//! ETC2ETC2,//! S3TCS3TC,//! ATITC
//        ATITC,//! TGATGA,//! Raw DataRAW_DATA,//! Unknown formatUNKNOWN};

2、增加两个方法的定义：

//判断是否是加密图片
bool isEncryptedPng(const unsigned char *data, ssize_t dataLen);
//解密
void deEncryptPng(unsigned char **copyData, const char *key, ssize_t dataLen);

CCImage.c添加：

1、实现Image::isEncryptedPng方法：

bool Image::isEncryptedPng(const unsigned char *data, ssize_t dataLen)
{if (dataLen <= 7 || memcmp("jiaozhi", data, 7) != 0) {return false;}return true;
}

2、实现Image::deEncryptPng解密方法:

void Image::deEncryptPng(unsigned char **copyData, const char *key, ssize_t dataLen) {static const unsigned char PNG_SIGNATURE[] = { 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a };static const unsigned char PNG_IEND[] = { 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4E, 0x44, 0xAE, 0x42, 0x60, 0x82 };unsigned char* data = *copyData;memcpy(data, PNG_SIGNATURE, 8);memcpy(data + (dataLen - 12), PNG_IEND, 12);unsigned char* destart = data + 8;unsigned char* de_end = data + dataLen - 13;ssize_t keyLen = strlen(key);ssize_t keyIndex = 0;for(; destart <= de_end; destart++, keyIndex++) {if (keyIndex >= keyLen)keyIndex = 0;*destart ^= key[keyIndex];}
}

3、修改检测图片类型的Image::detectFormat方法：

Image::Format Image::detectFormat(const unsigned char * data, ssize_t dataLen)
{if (isPng(data, dataLen)){return Format::PNG;}//新增判断else if (isEncryptedPng(data, dataLen)) {return Format::ENCRYPTEDPNG;}else if (isJpg(data, dataLen)){return Format::JPG;}else if (isTiff(data, dataLen)){return Format::TIFF;}else if (isWebp(data, dataLen)){return Format::WEBP;}else if (isPvr(data, dataLen)){return Format::PVR;}else if (isEtc(data, dataLen)){return Format::ETC;}else if (isS3TC(data, dataLen)){return Format::S3TC;}else{return Format::UNKNOWN;}
}

4、修改Image::initWithImageData，进行解密png

bool Image::initWithImageData(const unsigned char * data, ssize_t dataLen)
{bool ret = false;do{CC_BREAK_IF(! data || dataLen <= 0);unsigned char* unpackedData = nullptr;ssize_t unpackedLen = 0;//detect and unzip the compress fileif (ZipUtils::isCCZBuffer(data, dataLen)){unpackedLen = ZipUtils::inflateCCZBuffer(data, dataLen, &unpackedData);}else if (ZipUtils::isGZipBuffer(data, dataLen)){unpackedLen = ZipUtils::inflateMemory(const_cast<unsigned char*>(data), dataLen, &unpackedData);}else{unpackedData = const_cast<unsigned char*>(data);unpackedLen = dataLen;}_fileType = detectFormat(unpackedData, unpackedLen);switch (_fileType){//这个case块是增加的内容case Format::ENCRYPTEDPNG:{unsigned char* copyData = new unsigned char[unpackedLen + 13]; // 8 + 12 - 7memcpy(copyData + 8, unpackedData + 7, unpackedLen - 7);deEncryptPng(&copyData, "xxxxxxxx", unpackedLen + 13);  //注意这个"xxxxxxxx"是加密时设定的keyret = initWithPngData(copyData, unpackedLen + 13);delete [] copyData;}break;case Format::PNG:ret = initWithPngData(unpackedData, unpackedLen);break;case Format::JPG:ret = initWithJpgData(unpackedData, unpackedLen);break;case Format::TIFF:ret = initWithTiffData(unpackedData, unpackedLen);break;case Format::WEBP:ret = initWithWebpData(unpackedData, unpackedLen);break;case Format::PVR:ret = initWithPVRData(unpackedData, unpackedLen);break;case Format::ETC:ret = initWithETCData(unpackedData, unpackedLen);break;case Format::S3TC:ret = initWithS3TCData(unpackedData, unpackedLen);break;default:{// load and detect image formattImageTGA* tgaData = tgaLoadBuffer(unpackedData, unpackedLen);if (tgaData != nullptr && tgaData->status == TGA_OK){ret = initWithTGAData(tgaData);}else{CCLOG("Image: unsupported image format!");}free(tgaData);break;}}if(unpackedData != data){free(unpackedData);}} while (0);return ret;
}

三、加密操作

1、构建项目生成build文件夹。
2、双击encode.bat 。
3、加密完成，可以进行编译。

文章参考自：http://www.cnblogs.com/pixs-union/p/6226337.html