jni android 签名检测

apk防破解方案的一种方式。

把自己的发布和调试签名公钥，放于cpp，然后用jni从apk中提取包公钥进行对比可以简单加大破解难度。

这里我只拿到PackageInfo这一层，有兴趣的朋友可以拿

PackageManager或ApplicationInfo，这样更不怕被伪造。

先照例一个跨平台的接口

	class CheckPackage
	{
	public:
		CheckPackage(){}
		virtual ~CheckPackage(){}
	public:
		virtual bool checking() = 0;
	};
	typedef Milk::SingletonHolder<CheckPackage,UnImplCreatePolicy> CheckPackageManager;

	class CheckPackageAndroid
		: public CheckPackage
	{
	public:
		virtual bool checking();
	};

	template<>
	CheckPackage* UnImplCreatePolicy<CheckPackage>::Create()
	{
		return new CheckPackageAndroid;
	}
	template<>
	void UnImplCreatePolicy<CheckPackage>::Destroy(CheckPackage* p)
	{
		delete p;
	}

	bool CheckPackageAndroid::checking()
	{
		jobject _packageInfo = UtilJni::getPackageInfo();
		JniHelper& jh = JniHelperManager::Instance();
		JNIEnv* _env = jh.getJNIEnv();
		//
		jclass _jPackageInfo = _env->FindClass("android/content/pm/PackageInfo");
		//jclass _jSignature = _env->FindClass("android/content/pm/Signature");


		//jfieldID aId = env->GetFieldID(jcClass, "a", "[B");
		//jfieldID topicFieldId = (*env)->GetFieldID(env, objectClass,"topic", "Ljava/lang/String;");
		jfieldID _signatureFieldID = _env->GetFieldID(_jPackageInfo,"signatures","[Landroid/content/pm/Signature;");
		//
		jobject _signatureArrayObject = _env->GetObjectField(_packageInfo,_signatureFieldID);
		jobjectArray* _signatureArray = reinterpret_cast<jobjectArray*>(&_signatureArrayObject);
		//jobject     (*GetObjectArrayElement)(JNIEnv*, jobjectArray, jsize);
		jobject _signature = _env->GetObjectArrayElement(*_signatureArray,0);
		//jobject _signature = UtilJni::getSignature();
		if (_signature)
		{
			JniMethodInfo t;
			std::string ret("");


			JniHelper& jh = JniHelperManager::Instance();
			if (jh.getMethodInfo(t, "android/content/pm/Signature", "toCharsString", "()Ljava/lang/String;"))
			{
				jstring str = (jstring)t.env->CallObjectMethod(_signature,t.methodID);
				t.env->DeleteLocalRef(t.classID);
				ret = jh.jstring2string(str);
				t.env->DeleteLocalRef(str);
			}
			//dish_log("_signature :["<<ret<<"]");
			int i1 = ret.find(_PublicKeyRelease);
			int i2 = ret.find(_PublicKeyDebug);
			if (i1>0||i2>0)
			{
				return true;
			}
			else
			{
				return false;
			}
		}
		else
		{
			return false;
		}
	}

然后判别：

	if (!dish::<span style="font-family: Arial, Helvetica, sans-serif;">CheckPackage</span><span style="font-family: Arial, Helvetica, sans-serif;">Manager::Instance().checking())</span>
	{
		dish_log("PublicKey error.");
		dish::LayerNotityManager::Instance().logV(0,"Good luck!");
	}