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/*
* =====================================================================================
*
* Filename: md5.c
*
* Description: md5消息摘要算法的实现
*
* Version: 1.0
* Created: 04/04/2014 04:15:42 FFM
* Revision: none
* Compiler: gcc
*
* Author: Fluyy (), tulneer@gmail.com
* Blog: http://blog.fluyy.net
* Organization:
*
* =====================================================================================
*/
#include "md5_core.h"
#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 S(x,n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n)))
#define FF(a,b,c,d,k,s,t) \
{ \
a += F(b,c,d) + X[k] + t; a = S(a,s) + b; \
}
#define GG(a,b,c,d,k,s,t) \
{ \
a += G(b,c,d) + X[k] + t; a = S(a,s) + b; \
}
#define HH(a,b,c,d,k,s,t) \
{ \
a += H(b,c,d) + X[k] + t; a = S(a,s) + b; \
}
#define II(a,b,c,d,k,s,t) \
{ \
a += I(b,c,d) + X[k] + t; a = S(a,s) + b; \
}
unsigned char padding[64];
/*====================================
*
* md5初始化部分
* 初始化4个state初始值
*
*=====================================*/
int md5_init(CONTEXT *context){
context->state[0]=0x67452301;
context->state[1]=0xefcdab89;
context->state[2]=0x98badcfe;
context->state[3]=0x10325476;
context->count[0]=context->count[1]=0;
memset(padding,0,sizeof(padding));
padding[0]=0x80;
return 0;
}
/*====================================
*
* 对数据进行填充和分割成64个字节一组
* 然后循环对每组数据进行md5_process操作
*
*=====================================*/
int md5_update(CONTEXT *context,unsigned char *input,unsigned int inputlen){
/*left 表示缓冲区中剩余未处理的数据长度,单位byte*/
UINT4 left;
/*partlen 需要填充的数据长度,单位为byte*/
unsigned int partlen;
left=(UINT4)((context->count[0]>>3)&0x3f);
context->count[0]+=(UINT4)(inputlen<<3);
/*低位产生一个进位到高位*/
if(context->count[0]<(UINT4)(inputlen<<3))
context->count[1]++;
context->count[1] += ((UINT4)inputlen >> 29);
partlen=64-left;
/*新数据长度比需要填充的长度长时,可以组成一个新的128bit数据,可以进行一次md5 process*/
if(left && inputlen>=partlen){
memcpy((void*)(context->buffer+left),input,partlen);
md5_process(context,context->buffer);
input+=partlen;
inputlen-=partlen;
left=0;
}
/*循环处理缓存区内容*/
while(inputlen>=64){
md5_process(context,input);
input+=64;
inputlen-=64;
}
/*还有部分数据时,留到下次处理,保存下来,下次处理*/
if(inputlen>0){
memcpy((void *)(context->buffer+left),input,inputlen);
}
return 0;
}
/*
*===========================================
*
* md5_process操作主要是:
* 对数据进行4轮变换
*
*===========================================
*/
int md5_process(CONTEXT *context,unsigned char *data){
UINT4 A=context->state[0];
UINT4 B=context->state[1];
UINT4 C=context->state[2];
UINT4 D=context->state[3];
UINT4 X[16];
md5_decode(X,data,64);
//round1
FF( A, B, C, D, 0, 7, 0xD76AA478 );
FF( D, A, B, C, 1, 12, 0xE8C7B756 );
FF( C, D, A, B, 2, 17, 0x242070DB );
FF( B, C, D, A, 3, 22, 0xC1BDCEEE );
FF( A, B, C, D, 4, 7, 0xF57C0FAF );
FF( D, A, B, C, 5, 12, 0x4787C62A );
FF( C, D, A, B, 6, 17, 0xA8304613 );
FF( B, C, D, A, 7, 22, 0xFD469501 );
FF( A, B, C, D, 8, 7, 0x698098D8 );
FF( D, A, B, C, 9, 12, 0x8B44F7AF );
FF( C, D, A, B, 10, 17, 0xFFFF5BB1 );
FF( B, C, D, A, 11, 22, 0x895CD7BE );
FF( A, B, C, D, 12, 7, 0x6B901122 );
FF( D, A, B, C, 13, 12, 0xFD987193 );
FF( C, D, A, B, 14, 17, 0xA679438E );
FF( B, C, D, A, 15, 22, 0x49B40821 );
//round2
GG( A, B, C, D, 1, 5, 0xF61E2562 );
GG( D, A, B, C, 6, 9, 0xC040B340 );
GG( C, D, A, B, 11, 14, 0x265E5A51 );
GG( B, C, D, A, 0, 20, 0xE9B6C7AA );
GG( A, B, C, D, 5, 5, 0xD62F105D );
GG( D, A, B, C, 10, 9, 0x02441453 );
GG( C, D, A, B, 15, 14, 0xD8A1E681 );
GG( B, C, D, A, 4, 20, 0xE7D3FBC8 );
GG( A, B, C, D, 9, 5, 0x21E1CDE6 );
GG( D, A, B, C, 14, 9, 0xC33707D6 );
GG( C, D, A, B, 3, 14, 0xF4D50D87 );
GG( B, C, D, A, 8, 20, 0x455A14ED );
GG( A, B, C, D, 13, 5, 0xA9E3E905 );
GG( D, A, B, C, 2, 9, 0xFCEFA3F8 );
GG( C, D, A, B, 7, 14, 0x676F02D9 );
GG( B, C, D, A, 12, 20, 0x8D2A4C8A );
//round3
HH( A, B, C, D, 5, 4, 0xFFFA3942 );
HH( D, A, B, C, 8, 11, 0x8771F681 );
HH( C, D, A, B, 11, 16, 0x6D9D6122 );
HH( B, C, D, A, 14, 23, 0xFDE5380C );
HH( A, B, C, D, 1, 4, 0xA4BEEA44 );
HH( D, A, B, C, 4, 11, 0x4BDECFA9 );
HH( C, D, A, B, 7, 16, 0xF6BB4B60 );
HH( B, C, D, A, 10, 23, 0xBEBFBC70 );
HH( A, B, C, D, 13, 4, 0x289B7EC6 );
HH( D, A, B, C, 0, 11, 0xEAA127FA );
HH( C, D, A, B, 3, 16, 0xD4EF3085 );
HH( B, C, D, A, 6, 23, 0x04881D05 );
HH( A, B, C, D, 9, 4, 0xD9D4D039 );
HH( D, A, B, C, 12, 11, 0xE6DB99E5 );
HH( C, D, A, B, 15, 16, 0x1FA27CF8 );
HH( B, C, D, A, 2, 23, 0xC4AC5665 );
//round4
II( A, B, C, D, 0, 6, 0xF4292244 );
II( D, A, B, C, 7, 10, 0x432AFF97 );
II( C, D, A, B, 14, 15, 0xAB9423A7 );
II( B, C, D, A, 5, 21, 0xFC93A039 );
II( A, B, C, D, 12, 6, 0x655B59C3 );
II( D, A, B, C, 3, 10, 0x8F0CCC92 );
II( C, D, A, B, 10, 15, 0xFFEFF47D );
II( B, C, D, A, 1, 21, 0x85845DD1 );
II( A, B, C, D, 8, 6, 0x6FA87E4F );
II( D, A, B, C, 15, 10, 0xFE2CE6E0 );
II( C, D, A, B, 6, 15, 0xA3014314 );
II( B, C, D, A, 13, 21, 0x4E0811A1 );
II( A, B, C, D, 4, 6, 0xF7537E82 );
II( D, A, B, C, 11, 10, 0xBD3AF235 );
II( C, D, A, B, 2, 15, 0x2AD7D2BB );
II( B, C, D, A, 9, 21, 0xEB86D391 );
context->state[0]+=A;
context->state[1]+=B;
context->state[2]+=C;
context->state[3]+=D;
return 0;
}
/**/
int md5_final(CONTEXT *context,unsigned char *buf){
UINT4 left;
UINT4 padlen;
//数据要添加8个字节的数据长度
unsigned char msglen[8];
md5_encode(msglen,context->count,8);
//求出需要填充字节长度
left=(UINT4)((context->count[0]>>3) & 0x3f);
padlen=(left<56)?(56-left):(120-left);
//添加填充位
md5_update(context,padding,padlen);
//添加数据长度
md5_update(context,msglen,8);
//将最终值编码到buffer中,即将128位的信息输出
md5_encode(buf,context->state,16);
return 0;
}
/*
*=======================================================
*
*将UINT4信息编码为unsigned char
*将input里的数据转换为小端字节序存放在output中
*
*=======================================================
*/
int md5_encode (unsigned char *output, UINT4 *input, unsigned int len)
{
unsigned int i, j;
for (i = 0, j = 0; j < len; i++, j += 4){
output[j] = (unsigned char)(input[i] & 0xff);
output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
}
return 0;
}
/*===================================================
*
*将4个unsigned char 输出到unsigned int中
*
*====================================================
*/
int md5_decode (UINT4 *output, unsigned char *input, unsigned int len)
{
unsigned int i, j;
for (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);
return 0;
}