C++ MD5的源码实例详解

#ifndef MD5_H

#define MD5_H

#include

#include

/* Type define */

typedefunsignedcharbyte;

typedefunsignedintuint32;

usingstd::string;

usingstd::ifstream;

/* MD5 declaration. */

classMD5 {

public:

 MD5();

 MD5(constvoid*input,size_tlength);

 MD5(conststring &str);

 MD5(ifstream &in);

 voidupdate(constvoid*input,size_tlength);

 voidupdate(conststring &str);

 voidupdate(ifstream &in);

 constbyte* digest();

 string toString();

 voidreset();

private:

 voidupdate(constbyte *input,size_tlength);

 voidfinal();

 voidtransform(constbyte block[64]);

 voidencode(constuint32 *input, byte *output,size_tlength);

 voiddecode(constbyte *input, uint32 *output,size_tlength);

 string bytesToHexString(constbyte *input,size_tlength);

 /* class uncopyable */

 MD5(constMD5&);

 MD5& operator=(constMD5&);

private:

 uint32 _state[4];/* state (ABCD) */

 uint32 _count[2];/* number of bits, modulo 2^64 (low-order word first) */

 byte _buffer[64];/* input buffer */

 byte _digest[16];/* message digest */

 bool_finished;/* calculate finished ? */

 staticconstbyte PADDING[64];/* padding for calculate */

 staticconstcharHEX[16];

 staticconstsize_tBUFFER_SIZE = 1024;

};

#endif/*MD5_H*/

#include "md5.h"

usingnamespacestd;

/* 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.

*/

#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)))

/* ROTATE_LEFT rotates x left n bits.

*/

#define ROTATE_LEFT(x, n) (((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.

*/

#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);

}

constbyte MD5::PADDING[64] = { 0x80 };

constcharMD5::HEX[16] = {

 Ɔ',Ƈ',ƈ',Ɖ',

 Ɗ',Ƌ',ƌ',ƍ',

 Ǝ',Ə','a','b',

 'c','d','e','f'

};

/* Default construct. */

MD5::MD5() {

 reset();

}  

/* Construct a MD5 object with a input buffer. */

MD5::MD5(constvoid*input,size_tlength) {

 reset();

 update(input, length);

}

/* Construct a MD5 object with a string. */

MD5::MD5(conststring &str) {

 reset();

 update(str);

}

/* Construct a MD5 object with a file. */

MD5::MD5(ifstream &in) {

 reset();

 update(in);

}

/* Return the message-digest */

constbyte* MD5::digest() {

 if(!_finished) {

 _finished =true;

 final();

 }

 return_digest;

}

/* Reset the calculate state */

voidMD5::reset() {

 _finished =false;

 /* reset number of bits. */

 _count[0] = _count[1] = 0;

 /* Load magic initialization constants. */

 _state[0] = 0x67452301;

 _state[1] = 0xefcdab89;

 _state[2] = 0x98badcfe;

 _state[3] = 0x10325476;

}

/* Updating the context with a input buffer. */

voidMD5::update(constvoid*input,size_tlength) {

 update((constbyte*)input, length);

}

/* Updating the context with a string. */

voidMD5::update(conststring &str) {

 update((constbyte*)str.c_str(), str.length());

}

/* Updating the context with a file. */

voidMD5::update(ifstream &in) {

 if(!in)

 return;

 std::streamsize length;

 charbuffer[BUFFER_SIZE];

 while(!in.eof()) {

 in.read(buffer, BUFFER_SIZE);

 length = in.gcount();

 if(length > 0)

  update(buffer, length);

 }

 in.close();

}

/* MD5 block update operation. Continues an MD5 message-digest

operation, processing another message block, and updating the

context.

*/

voidMD5::update(constbyte *input,size_tlength) {

 uint32 i, index, partLen;

 _finished =false;

 /* Compute number of bytes mod 64 */

 index = (uint32)((_count[0] >> 3) & 0x3f);

 /* update number of bits */

 if((_count[0] += ((uint32)length << 3)) < ((uint32)length << 3))

 _count[1]++;

 _count[1] += ((uint32)length >> 29);

 partLen = 64 - index;

 /* transform as many times as possible. */

 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;

 }

 /* Buffer remaining input */

 memcpy(&_buffer[index], &input[i], length-i);

}

/* MD5 finalization. Ends an MD5 message-_digest operation, writing the

the message _digest and zeroizing the context.

*/

voidMD5::final() {

 byte bits[8];

 uint32 oldState[4];

 uint32 oldCount[2];

 uint32 index, padLen;

 /* Save current state and count. */

 memcpy(oldState, _state, 16);

 memcpy(oldCount, _count, 8);

 /* Save number of bits */

 encode(_count, bits, 8);

 /* Pad out to 56 mod 64. */

 index = (uint32)((_count[0] >> 3) & 0x3f);

 padLen = (index < 56) ? (56 - index) : (120 - index);

 update(PADDING, padLen);

 /* Append length (before padding) */

 update(bits, 8);

 /* Store state in digest */

 encode(_state, _digest, 16);

 /* Restore current state and count. */

 memcpy(_state, oldState, 16);

 memcpy(_count, oldCount, 8);

}

/* MD5 basic transformation. Transforms _state based on block. */

voidMD5::transform(constbyte block[64]) {

 uint32 a = _state[0], b = _state[1], c = _state[2], d = _state[3], x[16];

 decode(block, x, 64);

 /* 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;

}

/* Encodes input (ulong) into output (byte). Assumes length is

a multiple of 4.

*/

voidMD5::encode(constuint32 *input, byte *output,size_tlength) {

 for(size_ti=0, j=0; j

 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);

 }

}

/* Decodes input (byte) into output (ulong). Assumes length is

a multiple of 4.

*/

voidMD5::decode(constbyte *input, uint32 *output,size_tlength) {

 for(size_ti=0, j=0; j

 output[i] = ((uint32)input[j]) | (((uint32)input[j+1]) << 8) |

  (((uint32)input[j+2]) << 16) | (((uint32)input[j+3]) << 24);

 }

}

/* Convert byte array to hex string. */

string MD5::bytesToHexString(constbyte *input,size_tlength) {

 string str;

 str.reserve(length << 1);

 for(size_ti = 0; i < length; i++) {

 intt = input[i];

 inta = t / 16;

 intb = t % 16;

 str.append(1, HEX[a]);

 str.append(1, HEX[b]);

 }

 returnstr;

}

/* Convert digest to string value */

string MD5::toString() {

 returnbytesToHexString(digest(), 16);

}

#include "md5.h"

#include

usingnamespacestd;

voidPrintMD5(conststring &str, MD5 &md5) {

 cout <<"MD5(""<< str <<"") = "<< md5.toString() << endl;

}

string FileDigest(conststring &file) {

 ifstream in(file.c_str(), ios::binary);

 if(!in)

 return"";

 MD5 md5;

 std::streamsize length;

 charbuffer[1024];

 while(!in.eof()) {

 in.read(buffer, 1024);

 length = in.gcount();

 if(length > 0)

  md5.update(buffer, length);

 }

 in.close();

 returnmd5.toString();

}

intmain() {

 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);

 return0;

}

类MD5封装了与MD5相关的操作,其有

MD5();         //默认构造函数

MD5(constvoid*input,size_tlength);  //输入内存地址与长度信息的构造函数

MD5(conststring &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:

voidupdate(constvoid*input,size_tlength);//往MD5对象内添加内存块

voidupdate(conststring &str);   //添加字符串

voidupdate(ifstream &in);    //添加流

constbyte* 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

voidreset();       //重置,