md5.h文件：
typedef struct {
UINT4 state[4];
UINT4 count[2];
unsigned char buffer[64];
} MD5_CTX;
void MD5Init PROTO_LIST ((MD5_CTX *));
void MD5Update PROTO_LIST
((MD5_CTX *, unsigned char *, unsignedint));
void MD5Final PROTO_LIST ((unsigned char [16], MD5_CTX*));
****************************************************************************
global.h文件：
#ifndef PROTOTYPES
#define PROTOTYPES 0
#endif
typedef unsigned char *POINTER;
typedef unsigned short int UINT2;
typedef unsigned long int UINT4;
#if PROTOTYPES
#define PROTO_LIST(list) list
#else
#define PROTO_LIST(list) ()
#endif
*************************************************************
md5.c文件
#include "global.h"
#include "md5.h"
#include <stdio.h>
#include <string.h>
#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
static void MD5Transform PROTO_LIST ((UINT4 [4], unsigned char[64]));
static void Encode PROTO_LIST
((unsigned char *, UINT4 *, unsignedint));
static void Decode PROTO_LIST
((UINT4 *, unsigned char *, unsignedint));
static void MD5_memcpy PROTO_LIST ((POINTER, POINTER, unsignedint));
static void MD5_memset PROTO_LIST ((POINTER, int, unsignedint));
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
};
#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) +(UINT4)(ac);
(a) = ROTATE_LEFT ((a), (s));
(a) += (b);
}
#define GG(a, b, c, d, x, s, ac) {
(a) += G ((b), (c), (d)) + (x) +(UINT4)(ac);
(a) = ROTATE_LEFT ((a), (s));
(a) += (b);
}
#define HH(a, b, c, d, x, s, ac) {
(a) += H ((b), (c), (d)) + (x) +(UINT4)(ac);
(a) = ROTATE_LEFT ((a), (s));
(a) += (b);
}
#define II(a, b, c, d, x, s, ac) {
(a) += I ((b), (c), (d)) + (x) +(UINT4)(ac);
(a) = ROTATE_LEFT ((a), (s));
(a) += (b);
}
void MD5Init (MD5_CTX *context)
{
context->count[0] =context->count[1] = 0;
context->state[0] =0x67452301;
context->state[1] =0xefcdab89;
context->state[2] =0x98badcfe;
context->state[3] =0x10325476;
}
void MD5Update (MD5_CTX *context,unsigned char *input,unsignedint inputLen)
{
unsigned int i, index, partLen;
index = (unsignedint)((context->count[0]>> 3) & 0x3F);
if ((context->count[0] +=((UINT4)inputLen << 3))
<((UINT4)inputLen << 3))
context->count[1]++;
context->count[1] +=((UINT4)inputLen >> 29);
partLen = 64 - index;
if (inputLen >= partLen){
MD5_memcpy
((POINTER)&context->buffer[index],(POINTER)input, partLen);
MD5Transform (context->state,context->buffer);
for (i = partLen; i + 63 <inputLen; i += 64)
MD5Transform(context->state, &input[i]);
index = 0;
}
else
i = 0;
MD5_memcpy
((POINTER)&context->buffer[index],(POINTER)&input[i],
inputLen-i);
}
void MD5Final (unsigned char digest[16], MD5_CTX *context)
{
unsigned char bits[8];
unsigned int index, padLen;
Encode (bits,context->count, 8);
index = (unsignedint)((context->count[0]>> 3) & 0x3f);
padLen = (index < 56) ? (56- index) : (120 - index);
MD5Update (context, PADDING, padLen);
MD5Update (context, bits, 8);
Encode (digest,context->state, 16);
MD5_memset ((POINTER)context, 0, sizeof(*context));
}
void MD5Transform (UINT4 state[4],unsigned charblock[64])
{
UINT4 a = state[0], b = state[1], c =state[2], d = state[3], x[16];
Decode (x, block, 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;
MD5_memset ((POINTER)x, 0, sizeof(x));
}
static void 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);
}
}
void Decode (UINT4 *output,unsigned char *input,unsigned intlen)
{
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);
}
void MD5_memcpy (POINTER output,POINTER input,unsigned intlen)
{
unsigned int i;
for (i = 0; i < len;i++)
output[i] =input[i];
}
void MD5_memset (POINTER output,int value,unsigned intlen)
{
unsigned int i;
for (i = 0; i < len;i++)
((char *)output)[i] = (char)value;
}
void main()
{
int i;
unsigned char encrypt[200];
unsigned char decrypt[17];
MD5_CTX md5;
MD5Init(&md5);
scanf("%s",encrypt);
MD5Update(&md5,encrypt,strlen((char*)encrypt));
MD5Final(decrypt,&md5);
for(i=0;i<16;i++)
printf("x",decrypt[i]);
printf("n");
}
******************************************************************
实现将D:\test.txt文件用MD5算法加密，加密后的结果输出到md5.out.txt中去，修改main函数
void main()
{
int i,num;
FILE *fp,*code;
unsigned char *encrypt;
unsigned char decrypt[17];
MD5_CTX md5;
if((fp=fopen("D:\test.txt","r"))==NULL)
{
printf("Open file error!n");
exit(1);
}
if((code=fopen("D:\md5.out.txt","wb"))==NULL)
{
printf("open file error");
getchar();
exit(1);
}
num=0;
while(!feof(fp)) //求出文件的字符个数，动态分配内存
{
fgetc(fp);
num++;
}
printf("文件中的字符个数为：%dn",num-1);
encrypt=(char*)malloc(num);
fscanf(fp,"%s",encrypt);
encrypt[num-1]=' ';
MD5Init(&md5);
MD5Update(&md5,encrypt,num-1);
MD5Final(decrypt,&md5);
for(i=0;i<16;i++)
printf("x",decrypt[i]);
printf("n");
fwrite(decrypt,16,1,code);
fclose(code);
fclose(fp);
}
