C++实现MD5

MD5.h

#include<cstdio> #include<cstring> #include<algorithm> #include<cstdlib> #include<iostream> #include<cmath> typedef struct{ unsigned int count[2]; unsigned int state[4]; unsigned char buffer[64]; }MD5_CTX; #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;} void MD5Init(MD5_CTX *context); void MD5Update(MD5_CTX *context, unsigned char *input, unsigned int inputlen); void MD5Final(MD5_CTX *context, unsigned char digest[16]); void MD5Transform(unsigned int state[4], unsigned char block[64]); void MD5Encode(unsigned char *output, unsigned int *input, unsigned int len); void MD5Decode(unsigned int *output, unsigned char *input, unsigned int len); unsigned char PADDING[] = { 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 }; void MD5Init(MD5_CTX *context){ context->count[0]=0; context->count[1]=0; context->state[0]=0x67452301;//链接变量，注意与大端字节序的区别，内存中是小端字节序 context->state[1]=0xEFCDAB89; context->state[2]=0x98BADCFE; context->state[3]=0x10325476; } void MD5Update(MD5_CTX *context, unsigned char *input, unsigned int inputlen){ unsigned int i=0,index=0,partlen=0; index=(context->count[0]>>3)&0x3F;//模64字节的余数，第一次调用为0 partlen=64-index;//第一次partlen为64 //预留最前面的64位存放数据长度 context->count[0]+=inputlen<<3;//文本总的位数,低32位 if(context->count[0]<(inputlen<<3)) context->count[1]++; context->count[1]+=inputlen>>29;//先左移3,求出位数,再右移32位，求出左32位 if(inputlen>=partlen){ memcpy(&context->buffer[index], input, partlen); MD5Transform(context->state, context->buffer); //512位为1组 for(i=partlen;i+64<=inputlen;i+=64) MD5Transform(context->state,&input[i]); index=0; } else i=0; memcpy(&context->buffer[index], &input[i], inputlen-i);//最后剩下的一部分 } //32位md5 void MD5Final(MD5_CTX *context, unsigned char digest[16]){ unsigned int index=0,padlen=0; unsigned char bits[8]; index=(context->count[0]>>3)&0x3F;//模64字节的余数 padlen=(index<56)?(56-index):(120-index);//需要填充的长度，注意长度占8字节 MD5Encode(bits,context->count,8); MD5Update(context,PADDING,padlen); MD5Update(context,bits,8);//这里调用时,index=0 MD5Encode(digest,context->state,16); } void MD5Encode(unsigned char *output, unsigned int *input, unsigned int len){ unsigned int i = 0, j = 0;//len是char的长度 while (j<len){ 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; i++; j += 4; } } void MD5Decode(unsigned int *output, unsigned char *input, unsigned int len){ unsigned int i = 0, j = 0; while (j < len){ output[i] = (input[j]) | (input[j + 1] << 8) | (input[j + 2] << 16) | (input[j + 3] << 24); i++; j += 4; } } void MD5Transform(unsigned int state[4], unsigned char block[64]){ unsigned int a = state[0]; unsigned int b = state[1]; unsigned int c = state[2]; unsigned int d = state[3]; unsigned int x[16]; MD5Decode(x, block, 64); FF(a, b, c, d, x[0], 7, 0xd76aa478);//32位运算 FF(d, a, b, c, x[1], 12, 0xe8c7b756); FF(c, d, a, b, x[2], 17, 0x242070db); FF(b, c, d, a, x[3], 22, 0xc1bdceee); FF(a, b, c, d, x[4], 7, 0xf57c0faf); FF(d, a, b, c, x[5], 12, 0x4787c62a); FF(c, d, a, b, x[6], 17, 0xa8304613); FF(b, c, d, a, x[7], 22, 0xfd469501); FF(a, b, c, d, x[8], 7, 0x698098d8); FF(d, a, b, c, x[9], 12, 0x8b44f7af); FF(c, d, a, b, x[10], 17, 0xffff5bb1); FF(b, c, d, a, x[11], 22, 0x895cd7be); FF(a, b, c, d, x[12], 7, 0x6b901122); FF(d, a, b, c, x[13], 12, 0xfd987193); FF(c, d, a, b, x[14], 17, 0xa679438e); FF(b, c, d, a, x[15], 22, 0x49b40821); GG(a, b, c, d, x[1], 5, 0xf61e2562); GG(d, a, b, c, x[6], 9, 0xc040b340); GG(c, d, a, b, x[11], 14, 0x265e5a51); GG(b, c, d, a, x[0], 20, 0xe9b6c7aa); GG(a, b, c, d, x[5], 5, 0xd62f105d); GG(d, a, b, c, x[10], 9, 0x2441453); GG(c, d, a, b, x[15], 14, 0xd8a1e681); GG(b, c, d, a, x[4], 20, 0xe7d3fbc8); GG(a, b, c, d, x[9], 5, 0x21e1cde6); GG(d, a, b, c, x[14], 9, 0xc33707d6); GG(c, d, a, b, x[3], 14, 0xf4d50d87); GG(b, c, d, a, x[8], 20, 0x455a14ed); GG(a, b, c, d, x[13], 5, 0xa9e3e905); GG(d, a, b, c, x[2], 9, 0xfcefa3f8); GG(c, d, a, b, x[7], 14, 0x676f02d9); GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); HH(a, b, c, d, x[5], 4, 0xfffa3942); HH(d, a, b, c, x[8], 11, 0x8771f681); HH(c, d, a, b, x[11], 16, 0x6d9d6122); HH(b, c, d, a, x[14], 23, 0xfde5380c); HH(a, b, c, d, x[1], 4, 0xa4beea44); HH(d, a, b, c, x[4], 11, 0x4bdecfa9); HH(c, d, a, b, x[7], 16, 0xf6bb4b60); HH(b, c, d, a, x[10], 23, 0xbebfbc70); HH(a, b, c, d, x[13], 4, 0x289b7ec6); HH(d, a, b, c, x[0], 11, 0xeaa127fa); HH(c, d, a, b, x[3], 16, 0xd4ef3085); HH(b, c, d, a, x[6], 23, 0x4881d05); HH(a, b, c, d, x[9], 4, 0xd9d4d039); HH(d, a, b, c, x[12], 11, 0xe6db99e5); HH(c, d, a, b, x[15], 16, 0x1fa27cf8); HH(b, c, d, a, x[2], 23, 0xc4ac5665); II(a, b, c, d, x[0], 6, 0xf4292244); II(d, a, b, c, x[7], 10, 0x432aff97); II(c, d, a, b, x[14], 15, 0xab9423a7); II(b, c, d, a, x[5], 21, 0xfc93a039); II(a, b, c, d, x[12], 6, 0x655b59c3); II(d, a, b, c, x[3], 10, 0x8f0ccc92); II(c, d, a, b, x[10], 15, 0xffeff47d); II(b, c, d, a, x[1], 21, 0x85845dd1); II(a, b, c, d, x[8], 6, 0x6fa87e4f); II(d, a, b, c, x[15], 10, 0xfe2ce6e0); II(c, d, a, b, x[6], 15, 0xa3014314); II(b, c, d, a, x[13], 21, 0x4e0811a1); II(a, b, c, d, x[4], 6, 0xf7537e82); II(d, a, b, c, x[11], 10, 0xbd3af235); II(c, d, a, b, x[2], 15, 0x2ad7d2bb); II(b, c, d, a, x[9], 21, 0xeb86d391); state[0] += a; state[1] += b; state[2] += c; state[3] += d; }

test.cpp

#include"MD5.h" using namespace std; unsigned char encrypt[1024];//原文 unsigned char decrypt[16];//md5值 int main() { MD5_CTX md5; gets((char *)encrypt); MD5Init(&md5); MD5Update(&md5,encrypt,(int)strlen((char *)encrypt)); MD5Final(&md5,decrypt); bool bk=true; for(int j=0;j<16;j++){ printf("%02x",decrypt[j]); } printf("\n");//输出 return 0; }