C++ MD5源码：

md5.h:

#ifndef MD5_H #define MD5_H #include <string> #include <fstream> typedef unsigned char byte; typedef unsigned int uint32; using std::string; using std::ifstream; class MD5 { public: MD5(); MD5(const void *input, size_t length); MD5(const string &str); MD5(ifstream &in); void update(const void *input, size_t length); void update(const string &str); void update(ifstream &in); const byte* digest(); string toString(); void reset(); private: void update(const byte *input, size_t length); void final(); void transform(const byte block[64]); void encode(const uint32 *input, byte *output, size_t length); void decode(const byte *input, uint32 *output, size_t length); string bytesToHexString(const byte *input, size_t length); MD5(const MD5&); MD5& operator=(const MD5&); private: uint32 _state[4]; uint32 _count[2]; byte _buffer[64]; byte _digest[16]; bool _finished; static const byte PADDING[64]; static const char HEX[16]; static const size_t BUFFER_SIZE = 1024; }; #endif

md5.cpp:

#include "md5.h" using namespace std; #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 #define F(x, y, z) (((x) & (y)) | ((~x) & (z))) #define G(x, y, z) (((x) & (z)) | ((y) & (~z))) #define H(x, y, z) ((x) ^ (y) ^ (z)) #define I(x, y, z) ((y) ^ ((x) | (~z))) #define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n)))) #define FF(a, b, c, d, x, s, ac) { \ (a) += F ((b), (c), (d)) + (x) + ac; \ (a) = ROTATE_LEFT ((a), (s)); \ (a) += (b); \ } #define GG(a, b, c, d, x, s, ac) { \ (a) += G ((b), (c), (d)) + (x) + ac; \ (a) = ROTATE_LEFT ((a), (s)); \ (a) += (b); \ } #define HH(a, b, c, d, x, s, ac) { \ (a) += H ((b), (c), (d)) + (x) + ac; \ (a) = ROTATE_LEFT ((a), (s)); \ (a) += (b); \ } #define II(a, b, c, d, x, s, ac) { \ (a) += I ((b), (c), (d)) + (x) + ac; \ (a) = ROTATE_LEFT ((a), (s)); \ (a) += (b); \ } const byte MD5::PADDING[64] = { 0x80 }; const char MD5::HEX[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; MD5::MD5() { reset(); } MD5::MD5(const void *input, size_t length) { reset(); update(input, length); } MD5::MD5(const string &str) { reset(); update(str); } MD5::MD5(ifstream &in) { reset(); update(in); } const byte* MD5::digest() { if (!_finished) { _finished = true; final(); } return _digest; } void MD5::reset() { _finished = false; _count[0] = _count[1] = 0; _state[0] = 0x67452301; _state[1] = 0xefcdab89; _state[2] = 0x98badcfe; _state[3] = 0x10325476; } void MD5::update(const void *input, size_t length) { update((const byte*)input, length); } void MD5::update(const string &str) { update((const byte*)str.c_str(), str.length()); } void MD5::update(ifstream &in) { if (!in) return; std::streamsize length; char buffer[BUFFER_SIZE]; while (!in.eof()) { in.read(buffer, BUFFER_SIZE); length = in.gcount(); if (length > 0) update(buffer, length); } in.close(); } void MD5::update(const byte *input, size_t length) { uint32 i, index, partLen; _finished = false; index = (uint32)((_count[0] >> 3) & 0x3f); if((_count[0] += ((uint32)length << 3)) < ((uint32)length << 3)) _count[1]++; _count[1] += ((uint32)length >> 29); partLen = 64 - index; if(length >= partLen) { memcpy(&_buffer[index], input, partLen); transform(_buffer); for (i = partLen; i + 63 < length; i += 64) transform(&input[i]); index = 0; } else { i = 0; } memcpy(&_buffer[index], &input[i], length-i); } void MD5::final() { byte bits[8]; uint32 oldState[4]; uint32 oldCount[2]; uint32 index, padLen; memcpy(oldState, _state, 16); memcpy(oldCount, _count, 8); encode(_count, bits, 8); index = (uint32)((_count[0] >> 3) & 0x3f); padLen = (index < 56) ? (56 - index) : (120 - index); update(PADDING, padLen); update(bits, 8); encode(_state, _digest, 16); memcpy(_state, oldState, 16); memcpy(_count, oldCount, 8); } void MD5::transform(const byte block[64]) { uint32 a = _state[0], b = _state[1], c = _state[2], d = _state[3], x[16]; decode(block, x, 64); FF (a, b, c, d, x[ 0], S11, 0xd76aa478); FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); FF (c, d, a, b, x[ 2], S13, 0x242070db); FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); FF (d, a, b, c, x[ 5], S12, 0x4787c62a); FF (c, d, a, b, x[ 6], S13, 0xa8304613); FF (b, c, d, a, x[ 7], S14, 0xfd469501); FF (a, b, c, d, x[ 8], S11, 0x698098d8); FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); FF (c, d, a, b, x[10], S13, 0xffff5bb1); FF (b, c, d, a, x[11], S14, 0x895cd7be); FF (a, b, c, d, x[12], S11, 0x6b901122); FF (d, a, b, c, x[13], S12, 0xfd987193); FF (c, d, a, b, x[14], S13, 0xa679438e); FF (b, c, d, a, x[15], S14, 0x49b40821); GG (a, b, c, d, x[ 1], S21, 0xf61e2562); GG (d, a, b, c, x[ 6], S22, 0xc040b340); GG (c, d, a, b, x[11], S23, 0x265e5a51); GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); GG (a, b, c, d, x[ 5], S21, 0xd62f105d); GG (d, a, b, c, x[10], S22, 0x2441453); GG (c, d, a, b, x[15], S23, 0xd8a1e681); GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); GG (d, a, b, c, x[14], S22, 0xc33707d6); GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); GG (b, c, d, a, x[ 8], S24, 0x455a14ed); GG (a, b, c, d, x[13], S21, 0xa9e3e905); GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); GG (c, d, a, b, x[ 7], S23, 0x676f02d9); GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); HH (a, b, c, d, x[ 5], S31, 0xfffa3942); HH (d, a, b, c, x[ 8], S32, 0x8771f681); HH (c, d, a, b, x[11], S33, 0x6d9d6122); HH (b, c, d, a, x[14], S34, 0xfde5380c); HH (a, b, c, d, x[ 1], S31, 0xa4beea44); HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); HH (b, c, d, a, x[10], S34, 0xbebfbc70); HH (a, b, c, d, x[13], S31, 0x289b7ec6); HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); HH (b, c, d, a, x[ 6], S34, 0x4881d05); HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); HH (d, a, b, c, x[12], S32, 0xe6db99e5); HH (c, d, a, b, x[15], S33, 0x1fa27cf8); HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); II (a, b, c, d, x[ 0], S41, 0xf4292244); II (d, a, b, c, x[ 7], S42, 0x432aff97); II (c, d, a, b, x[14], S43, 0xab9423a7); II (b, c, d, a, x[ 5], S44, 0xfc93a039); II (a, b, c, d, x[12], S41, 0x655b59c3); II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); II (c, d, a, b, x[10], S43, 0xffeff47d); II (b, c, d, a, x[ 1], S44, 0x85845dd1); II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); II (d, a, b, c, x[15], S42, 0xfe2ce6e0); II (c, d, a, b, x[ 6], S43, 0xa3014314); II (b, c, d, a, x[13], S44, 0x4e0811a1); II (a, b, c, d, x[ 4], S41, 0xf7537e82); II (d, a, b, c, x[11], S42, 0xbd3af235); II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); II (b, c, d, a, x[ 9], S44, 0xeb86d391); _state[0] += a; _state[1] += b; _state[2] += c; _state[3] += d; } void MD5::encode(const uint32 *input, byte *output, size_t length) { for(size_t i=0, j=0; j<length; i++, j+=4) { output[j]= (byte)(input[i] & 0xff); output[j+1] = (byte)((input[i] >> 8) & 0xff); output[j+2] = (byte)((input[i] >> 16) & 0xff); output[j+3] = (byte)((input[i] >> 24) & 0xff); } } void MD5::decode(const byte *input, uint32 *output, size_t length) { for(size_t i=0, j=0; j<length; i++, j+=4) { output[i] = ((uint32)input[j]) | (((uint32)input[j+1]) << 8) | (((uint32)input[j+2]) << 16) | (((uint32)input[j+3]) << 24); } } string MD5::bytesToHexString(const byte *input, size_t length) { string str; str.reserve(length << 1); for(size_t i = 0; i < length; i++) { int t = input[i]; int a = t / 16; int b = t % 16; str.append(1, HEX[a]); str.append(1, HEX[b]); } return str; } string MD5::toString() { return bytesToHexString(digest(), 16); }

测试文件test.cpp:

#include "md5.h" #include <iostream> using namespace std; void PrintMD5(const string &str, MD5 &md5) { cout << "MD5(\"" << str << "\") = " << md5.toString() << endl; } string FileDigest(const string &file) { ifstream in(file.c_str(), ios::binary); if (!in) return ""; MD5 md5; std::streamsize length; char buffer[1024]; while (!in.eof()) { in.read(buffer, 1024); length = in.gcount(); if (length > 0) md5.update(buffer, length); } in.close(); return md5.toString(); } int main() { cout << MD5("abc").toString() << endl; cout << MD5(ifstream("D:\\test.txt")).toString() << endl; cout << MD5(ifstream("D:\\test.exe", ios::binary)).toString() << endl; cout << FileDigest("D:\\test.exe") << endl; MD5 md5; md5.update(""); PrintMD5("", md5); md5.update("a"); PrintMD5("a", md5); md5.update("bc"); PrintMD5("abc", md5); md5.update("defghijklmnopqrstuvwxyz"); PrintMD5("abcdefghijklmnopqrstuvwxyz", md5); md5.reset(); md5.update("message digest"); PrintMD5("message digest", md5); md5.reset(); md5.update(ifstream("D:\\test.txt")); PrintMD5("D:\\test.txt", md5); return 0; }

类MD5封装了与MD5相关的操作,其有

4个构造函数:

MD5(); //默认构造函数MD5(const void *input, size_t length); //输入内存地址与长度信息的构造函数MD5(const string &str); //输入字符串的构造函数MD5(ifstream &in); //输入流的构造函数3个Update函数:void update(const void *input, size_t length); //往MD5对象内添加内存块void update(const string &str); //添加字符串void update(ifstream &in); //添加流const byte* digest(); //计算MD5码,并返回指向它的指针string toString(); //计算MD5,并返回其对应的字符串void reset(); //重置,

test.cpp文件内的main函数描述了MD5类的用法。

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