Android(安卓)通过JNI C++进行MD5加密
最近升级了Android Studio 3.0.1。版本升级,越是觉得好用了。
Android Studio使用JNI之前觉得是一件比较麻烦的事,官方文档也不多,有点无从下手。本篇以CMake方式说说如何利用JNI方式使用C++进行MD5加密,这样经过Native的方式不容易被反编译出来,所以加点复杂的盐,安全性会更高。
1、新建项目时勾选C++支持选项。然后后面每一步默认即可。
2、默认会在cpp目录下生成native-lib.cpp
的文件,默认我们与C/C++代码的交互就在这个文件中。配置实在CMakeList.txt
(app模块根目录下)文件中。
3、如图我们添加MD5.h和MD5.cpp文件,并在CMakeList.txt
配置
4、完成这一步后,编写MD5的实现代码。
MD5.h
如下:
#include #include // a small class for calculating MD5 hashes of strings or byte arrays// it is not meant to be fast or secure//// usage: 1) feed it blocks of uchars with update()// 2) finalize()// 3) get hexdigest() string// or// MD5(std::string).hexdigest()//// assumes that char is 8 bit and int is 32 bitclass MD5{public: typedef unsigned int size_type; // must be 32bit MD5(); MD5(const std::string& text); void update(const unsigned char *buf, size_type length); void update(const char *buf, size_type length); MD5& finalize(); std::string hexdigest() const; friend std::ostream& operator<<(std::ostream&, MD5 md5);private: void init(); typedef unsigned char uint1; // 8bit typedef unsigned int uint4; // 32bit enum { blocksize = 64 }; // VC6 won't eat a const static int here void transform(const uint1 block[blocksize]); static void decode(uint4 output[], const uint1 input[], size_type len); static void encode(uint1 output[], const uint4 input[], size_type len); bool finalized; uint1 buffer[blocksize]; // bytes that didn't fit in last 64 byte chunk uint4 count[2]; // 64bit counter for number of bits (lo, hi) uint4 state[4]; // digest so far uint1 digest[16]; // the result // low level logic operations static inline uint4 F(uint4 x, uint4 y, uint4 z); static inline uint4 G(uint4 x, uint4 y, uint4 z); static inline uint4 H(uint4 x, uint4 y, uint4 z); static inline uint4 I(uint4 x, uint4 y, uint4 z); static inline uint4 rotate_left(uint4 x, int n); static inline void FF(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac); static inline void GG(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac); static inline void HH(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac); static inline void II(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac);};std::string md5(const std::string str);
MD5.cpp如下:
#include "MD5.h"/* system implementation headers */#include #include // Constants for MD5Transform routine.#define S11 7#define S12 12#define S13 17#define S14 22#define S21 5#define S22 9#define S23 14#define S24 20#define S31 4#define S32 11#define S33 16#define S34 23#define S41 6#define S42 10#define S43 15#define S44 21///////////////////////////////////////////////// F, G, H and I are basic MD5 functions.inline MD5::uint4 MD5::F(uint4 x, uint4 y, uint4 z) { return x&y | ~x&z;}inline MD5::uint4 MD5::G(uint4 x, uint4 y, uint4 z) { return x&z | y&~z;}inline MD5::uint4 MD5::H(uint4 x, uint4 y, uint4 z) { return x^y^z;}inline MD5::uint4 MD5::I(uint4 x, uint4 y, uint4 z) { return y ^ (x | ~z);}// rotate_left rotates x left n bits.inline MD5::uint4 MD5::rotate_left(uint4 x, int n) { return (x << n) | (x >> (32 - n));}// FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.// Rotation is separate from addition to prevent recomputation.inline void MD5::FF(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac) { a = rotate_left(a + F(b, c, d) + x + ac, s) + b;}inline void MD5::GG(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac) { a = rotate_left(a + G(b, c, d) + x + ac, s) + b;}inline void MD5::HH(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac) { a = rotate_left(a + H(b, c, d) + x + ac, s) + b;}inline void MD5::II(uint4 &a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac) { a = rotate_left(a + I(b, c, d) + x + ac, s) + b;}//////////////////////////////////////////////// default ctor, just initailizeMD5::MD5(){ init();}//////////////////////////////////////////////// nifty shortcut ctor, compute MD5 for string and finalize it right awayMD5::MD5(const std::string &text){ init(); update(text.c_str(), text.length()); finalize();}//////////////////////////////void MD5::init(){ finalized = false; count[0] = 0; count[1] = 0; // load magic initialization constants. state[0] = 0x67452301; state[1] = 0xefcdab89; state[2] = 0x98badcfe; state[3] = 0x10325476;}//////////////////////////////// decodes input (unsigned char) into output (uint4). Assumes len is a multiple of 4.void MD5::decode(uint4 output[], const uint1 input[], size_type len){ for (unsigned int i = 0, j = 0; j < len; i++, j += 4) output[i] = ((uint4)input[j]) | (((uint4)input[j + 1]) << 8) | (((uint4)input[j + 2]) << 16) | (((uint4)input[j + 3]) << 24);}//////////////////////////////// encodes input (uint4) into output (unsigned char). Assumes len is// a multiple of 4.void MD5::encode(uint1 output[], const uint4 input[], size_type len){ for (size_type i = 0, j = 0; j < len; i++, j += 4) { output[j] = input[i] & 0xff; output[j + 1] = (input[i] >> 8) & 0xff; output[j + 2] = (input[i] >> 16) & 0xff; output[j + 3] = (input[i] >> 24) & 0xff; }}//////////////////////////////// apply MD5 algo on a blockvoid MD5::transform(const uint1 block[blocksize]){ uint4 a = state[0], b = state[1], c = state[2], d = state[3], x[16]; decode(x, block, blocksize); /* Round 1 */ FF(a, b, c, d, x[0], S11, 0xd76aa478); /* 1 */ FF(d, a, b, c, x[1], S12, 0xe8c7b756); /* 2 */ FF(c, d, a, b, x[2], S13, 0x242070db); /* 3 */ FF(b, c, d, a, x[3], S14, 0xc1bdceee); /* 4 */ FF(a, b, c, d, x[4], S11, 0xf57c0faf); /* 5 */ FF(d, a, b, c, x[5], S12, 0x4787c62a); /* 6 */ FF(c, d, a, b, x[6], S13, 0xa8304613); /* 7 */ FF(b, c, d, a, x[7], S14, 0xfd469501); /* 8 */ FF(a, b, c, d, x[8], S11, 0x698098d8); /* 9 */ FF(d, a, b, c, x[9], S12, 0x8b44f7af); /* 10 */ FF(c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */ FF(b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */ FF(a, b, c, d, x[12], S11, 0x6b901122); /* 13 */ FF(d, a, b, c, x[13], S12, 0xfd987193); /* 14 */ FF(c, d, a, b, x[14], S13, 0xa679438e); /* 15 */ FF(b, c, d, a, x[15], S14, 0x49b40821); /* 16 */ /* Round 2 */ GG(a, b, c, d, x[1], S21, 0xf61e2562); /* 17 */ GG(d, a, b, c, x[6], S22, 0xc040b340); /* 18 */ GG(c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */ GG(b, c, d, a, x[0], S24, 0xe9b6c7aa); /* 20 */ GG(a, b, c, d, x[5], S21, 0xd62f105d); /* 21 */ GG(d, a, b, c, x[10], S22, 0x2441453); /* 22 */ GG(c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */ GG(b, c, d, a, x[4], S24, 0xe7d3fbc8); /* 24 */ GG(a, b, c, d, x[9], S21, 0x21e1cde6); /* 25 */ GG(d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */ GG(c, d, a, b, x[3], S23, 0xf4d50d87); /* 27 */ GG(b, c, d, a, x[8], S24, 0x455a14ed); /* 28 */ GG(a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */ GG(d, a, b, c, x[2], S22, 0xfcefa3f8); /* 30 */ GG(c, d, a, b, x[7], S23, 0x676f02d9); /* 31 */ GG(b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */ /* Round 3 */ HH(a, b, c, d, x[5], S31, 0xfffa3942); /* 33 */ HH(d, a, b, c, x[8], S32, 0x8771f681); /* 34 */ HH(c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */ HH(b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */ HH(a, b, c, d, x[1], S31, 0xa4beea44); /* 37 */ HH(d, a, b, c, x[4], S32, 0x4bdecfa9); /* 38 */ HH(c, d, a, b, x[7], S33, 0xf6bb4b60); /* 39 */ HH(b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */ HH(a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */ HH(d, a, b, c, x[0], S32, 0xeaa127fa); /* 42 */ HH(c, d, a, b, x[3], S33, 0xd4ef3085); /* 43 */ HH(b, c, d, a, x[6], S34, 0x4881d05); /* 44 */ HH(a, b, c, d, x[9], S31, 0xd9d4d039); /* 45 */ HH(d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */ HH(c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */ HH(b, c, d, a, x[2], S34, 0xc4ac5665); /* 48 */ /* Round 4 */ II(a, b, c, d, x[0], S41, 0xf4292244); /* 49 */ II(d, a, b, c, x[7], S42, 0x432aff97); /* 50 */ II(c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */ II(b, c, d, a, x[5], S44, 0xfc93a039); /* 52 */ II(a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */ II(d, a, b, c, x[3], S42, 0x8f0ccc92); /* 54 */ II(c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */ II(b, c, d, a, x[1], S44, 0x85845dd1); /* 56 */ II(a, b, c, d, x[8], S41, 0x6fa87e4f); /* 57 */ II(d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */ II(c, d, a, b, x[6], S43, 0xa3014314); /* 59 */ II(b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */ II(a, b, c, d, x[4], S41, 0xf7537e82); /* 61 */ II(d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */ II(c, d, a, b, x[2], S43, 0x2ad7d2bb); /* 63 */ II(b, c, d, a, x[9], S44, 0xeb86d391); /* 64 */ state[0] += a; state[1] += b; state[2] += c; state[3] += d; // Zeroize sensitive information. memset(x, 0, sizeof x);}//////////////////////////////// MD5 block update operation. Continues an MD5 message-digest// operation, processing another message blockvoid MD5::update(const unsigned char input[], size_type length){ // compute number of bytes mod 64 size_type index = count[0] / 8 % blocksize; // Update number of bits if ((count[0] += (length << 3)) < (length << 3)) count[1]++; count[1] += (length >> 29); // number of bytes we need to fill in buffer size_type firstpart = 64 - index; size_type i; // transform as many times as possible. if (length >= firstpart) { // fill buffer first, transform memcpy(&buffer[index], input, firstpart); transform(buffer); // transform chunks of blocksize (64 bytes) for (i = firstpart; i + blocksize <= length; i += blocksize) transform(&input[i]); index = 0; } else i = 0; // buffer remaining input memcpy(&buffer[index], &input[i], length - i);}//////////////////////////////// for convenience provide a verson with signed charvoid MD5::update(const char input[], size_type length){ update((const unsigned char*)input, length);}//////////////////////////////// MD5 finalization. Ends an MD5 message-digest operation, writing the// the message digest and zeroizing the context.MD5& MD5::finalize(){ static unsigned char padding[64] = { 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; if (!finalized) { // Save number of bits unsigned char bits[8]; encode(bits, count, 8); // pad out to 56 mod 64. size_type index = count[0] / 8 % 64; size_type padLen = (index < 56) ? (56 - index) : (120 - index); update(padding, padLen); // Append length (before padding) update(bits, 8); // Store state in digest encode(digest, state, 16); // Zeroize sensitive information. memset(buffer, 0, sizeof buffer); memset(count, 0, sizeof count); finalized = true; } return *this;}//////////////////////////////// return hex representation of digest as stringstd::string MD5::hexdigest() const{ if (!finalized) return ""; char buf[33]; for (int i = 0; i < 16; i++) sprintf(buf + i * 2, "%02x", digest[i]); buf[32] = 0; return std::string(buf);}//////////////////////////////std::ostream& operator<<(std::ostream& out, MD5 md5){ return out << md5.hexdigest();}//////////////////////////////std::string md5(const std::string str){ MD5 md5 = MD5(str); return md5.hexdigest();}
5、完成这一步后,make一下project。然后在Java和native-lib.cpp
中分别编写MD5的测试代码:
比如在MainActivity.java
中定义native的方法:
// Used to load the 'native-lib' library on application startup.static { System.loadLibrary("native-lib");}public native String getMd5(String origin);
然后在native-lib.cpp
中完成实现:
//记得导入头文件#include "MD5.h"//使用c中的md5加密,可以将盐加入不容易被反编译出来JNIEXPORT jstring JNICALLJava_com_dengpan_MainActivity_getMd5(JNIEnv *env, jobject, jstring str) { const char *originStr; //将jstring转化成char *类型 originStr = env->GetStringUTFChars(str, false); MD5 md5 = MD5(originStr); std::string md5Result = md5.hexdigest(); //将char *类型转化成jstring返回给Java层 return env->NewStringUTF(md5Result.c_str());}
6、于是运行程序在MainActivity的onCreate方法中可以看到程序打印出结果。
System.out.println("MD5加密结果:" + getMd5("123456"));##运行结果I/System.out: MD5加密结果:e10adc3949ba59abbe56e057f20f883e
另外,JNI中常用在C++中打印出log,需要有如下配置:
#include #define LOG_TAG "lib_native_log"#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__)#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)
另外,在JNI中调用Java定义的方法:比如在MainActivity中定义
//定义和native交互的方法public native void toast();//....//定义被C++ 调用的方法public void toastMain(Context c){ Toast.makeText(c, "通过Native调用出现的提示", Toast.LENGTH_SHORT).show();}
那么在native-lib.cpp中定义方法:
//需要调用此方法,则此方法定义在调用方法前。获取全局Contextjobject getGlobalContext(JNIEnv *env){ //获取Activity Thread的实例对象 jclass activityThread = env->FindClass("android/app/ActivityThread"); jmethodID currentActivityThread = env->GetStaticMethodID(activityThread, "currentActivityThread", "()Landroid/app/ActivityThread;"); jobject at = env->CallStaticObjectMethod(activityThread, currentActivityThread); //获取Application,也就是全局的Context jmethodID getApplication = env->GetMethodID(activityThread, "getApplication", "()Landroid/app/Application;"); jobject context = env->CallObjectMethod(at, getApplication); return context;}JNIEXPORT void JNICALLJava_com_dengpan_MainActivity_toast(JNIEnv *env, jobject obj) { jclass dpclazz = env->FindClass("com/dengpan/MainActivity"); if(dpclazz==0){ LOGE("find class error"); return; } LOGI("find class "); //2 寻找class里面的方法 jmethodID method1 = env->GetMethodID(dpclazz,"toastMain","(Landroid/content/Context;)V");// if(method1==0){ LOGE("find method1 error"); return; } LOGI("find method1"); //3 .调用这个方法 // void (*CallVoidMethod)(JNIEnv*, jobject, jmethodID, ...); env->CallVoidMethod(obj,method1,getGlobalContext(env));}
注意,在native-lib.cpp定义的方法一定要放在
extern "C" {}
里面,不然编译运行时会报一些链接错误。
CMake的方式会自动将CPP文件编译成so文件拷贝打包到apk文件中。 如图:
至此JNI方法调用暂时写到这儿。
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