计算文件MD5值 应用层篇

 

方法一：调用windows提供的dll文件Cryptdll.dll

/******************************************test.c******************************************/

#include <windows.h>
#include <stdio.h>

//定义用于MD5值计算的结构体
#ifndef MD5_CTX
typedef struct {
    ULONG i[2];
    ULONG buf[4];
    unsigned char in[64];
    unsigned char digest[16];
} MD5_CTX;
#endif

//定义函数指针
typedef void (WINAPI* PMD5Init)(MD5_CTX* context);
typedef void (WINAPI* PMD5Final)(MD5_CTX* context);
typedef void (WINAPI* PMD5Update)(MD5_CTX* context,const unsigned char* input, unsigned int inlen);

int main()
{

FILE * ff;
unsigned long nSize = 1024;
char *rBuff = malloc(sizeof(char)*nSize);
unsigned long rCount = 0;
MD5_CTX context;

//加载微软提供MD5计算的dll文件
HMODULE hdll = LoadLibrary("Cryptdll.dll");
PMD5Init m_pFuncMD5Init = NULL;
PMD5Final m_pFuncMD5Final = NULL;
PMD5Update m_pFuncMD5Update = NULL;

if (hdll == NULL)
{
   printf("load dll Cryptdll faild\n");
   exit(1);
}
//获得相应的函数地址
m_pFuncMD5Init = (PMD5Init)GetProcAddress(hdll,"MD5Init");
m_pFuncMD5Final = (PMD5Final)GetProcAddress(hdll,"MD5Final");
m_pFuncMD5Update = (PMD5Update)GetProcAddress(hdll,"MD5Update");

if (!(m_pFuncMD5Update&&m_pFuncMD5Init&&m_pFuncMD5Final))
{
   FreeLibrary(hdll);
   printf("get function faild\n");
   exit(2);
}

//初始化context
ZeroMemory(&context,sizeof(MD5_CTX));
m_pFuncMD5Init(&context);

//打开一个测试文件
if (!(ff = fopen("C:\\windows\\regedit.exe","rb")))
{
   printf("open file faild\n");
   exit(3);
}
while (rCount = fread(rBuff,sizeof(char),nSize,ff))
{
   m_pFuncMD5Update(&context,rBuff,rCount);
}
m_pFuncMD5Final(&context);
//此处下断点，调试状态从Watch中查看cnotext.digest域为文件MD5值
  
fclose(ff);
free(rBuff);
}

方法二：自己实现（这里给出内联汇编的方式，C语言方式见附件）

/******************************************md5.h 文件******************************************/

#include <windows.h>

typedef struct {
unsigned long state[4];    //encypted message
unsigned long count[2];    //bits of plaintext
unsigned char buffer[64];
}MD5_CTX;

void MD5Init(MD5_CTX *);
void MD5Update(MD5_CTX *, unsigned char *, unsigned int);//待加密的明文是中间那个参数
void MD5Final(MD5_CTX *);

#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 a esi
#define b edi
#define c edx
#define d ebx
#define tmp1 eax
#define tmp2 ecx

#define x(i) [x+4*i]

static void MD5Transform (unsigned long [4], unsigned char [64]);

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 FF(a, b, c, d, x, s, ac) \
__asm mov tmp1,b \
__asm and tmp1,c \
__asm mov tmp2,b \
__asm not tmp2 \
__asm and tmp2,d \
__asm or tmp2,tmp1 \
__asm lea a,[tmp2+a+ac] \
__asm add a,x \
__asm rol a,s \
__asm add a,b \

#define GG(a, b, c, d, x, s, ac) \
__asm mov tmp1,b \
__asm and tmp1,d \
__asm mov tmp2,d \
__asm not tmp2 \
__asm and tmp2,c \
__asm or tmp2,tmp1 \
__asm lea a,[tmp2+a+ac] \
__asm add a,x \
__asm rol a,s \
__asm add a,b

#define HH(a,b,c, d, x, s, ac) \
__asm mov tmp2,b \
__asm xor tmp2,c \
__asm xor tmp2,d \
__asm lea a,[tmp2+a+ac] \
__asm add a,x \
__asm rol a,s \
__asm add a,b

#define II(a, b, c, d, x, s, ac) \
__asm mov tmp2,d \
__asm not tmp2 \
__asm or tmp2,b \
__asm xor tmp2,c \
__asm lea a,[tmp2+a+ac] \
__asm add a,x \
__asm rol a,s \
__asm add a,b

void MD5Init (MD5_CTX *context)
{
context->count[0] = context->count[1] = 0;
context->state[0] = 0x67452301;   //内存中顺序是01234567
context->state[1] = 0xefcdab89;   //内存中顺序是89abcdef
context->state[2] = 0x98badcfe;   //内存中顺序是fedcba98
context->state[3] = 0x10325476;   //内存中顺序是76543210
}

void MD5Update (MD5_CTX *context, unsigned char *input, unsigned int inputLen)
{
unsigned int i, index, partLen;

index = (unsigned int)((context->count[0] >> 3) & 0x3F);

if ((context->count[0] += ((unsigned long)inputLen << 3)) < ((unsigned long)inputLen << 3))
   context->count[1]++;
context->count[1] += ((unsigned long)inputLen >> 29);

partLen = 64 - index;

if (inputLen >= partLen) {
   CopyMemory(&context->buffer[index],input, partLen);
   MD5Transform (context->state, context->buffer);
  
   for (i = partLen; i + 63 < inputLen; i += 64){}
   index = 0;
}
else
   i = 0;

/* Buffer remaining input */
CopyMemory(&context->buffer[index],&input[i],inputLen-i);
}

void MD5Final (MD5_CTX *context)
{
unsigned char bits[8];
unsigned int index, padLen;

CopyMemory(bits,context->count,8);

index = (unsigned int)((context->count[0] >> 3) & 0x3f);
padLen = (index < 56) ? (56 - index) : (120 - index);
MD5Update (context, PADDING, padLen);
MD5Update (context, bits, 8);
}

static void MD5Transform (unsigned long state[4], unsigned char block[64])
{
unsigned long x[16];
__asm {
   //initial
/*   mov a,0x67452301
   mov b,0xefcdab89
   mov c,0x98badcfe
   mov d,0x10325476
*/
   mov tmp1,DWORD PTR [state]
   mov a,DWORD PTR [tmp1]
   mov b,DWORD PTR [tmp1+4]
   mov c,DWORD PTR [tmp1+8]
   mov d,DWORD PTR [tmp1+12]
   //copy string from block to state
   //考虑到用API会影响寄存器，所以自己实现这一段内存拷贝
   push esi
   push edi
   
   xor ecx,ecx
   mov esi,dword ptr [block]
   lea edi,[x]
ROLL:
   mov eax,dword ptr [esi+ecx]
   mov dword ptr [edi+ecx],eax
   add ecx,4
   cmp ecx,64
   jb ROLL
   
   pop edi
   pop esi
}

/* 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 */

__asm {
   mov tmp1,DWORD PTR [state]
   add DWORD PTR [tmp1],a
   add DWORD PTR [tmp1+4],b
   add DWORD PTR [tmp1+8],c
   add DWORD PTR [tmp1+12],d
}
}

/*************************************/test.c文件******************************************/

#include "md5.h"
#include <stdio.h>
#include <windows.h>

int main()
{
MD5_CTX context;
FILE* ff;
LPCTSTR m_filename = "C:\\windows\\regedit.exe";
unsigned long dwSize = 64;
unsigned long rCount = 0;
unsigned char * rbuff = malloc(sizeof(unsigned char)*dwSize);
char printBuf[64];

if(!(ff=fopen(m_filename,"rb")))
{
   printf("open file faild……\n");
   exit(1);
}

MD5Init(&context);
while(rCount = fread(rbuff,sizeof(char),dwSize,ff))
{
   MD5Update(&context, rbuff,rCount);
}
MD5Final(&context);
free(rbuff);
fclose(ff);

//以下为输出文件的 MD5值
RtlFillMemory(&context.buffer,64,'\0');
memcpy(context.buffer,(unsigned char*)context.state,16);//先将结果拷贝到context.buffer中
{//转化成字符串输出
   unsigned long i=0;
   for (;i<16;i++)
   {
    itoa((unsigned char)context.buffer[i],&printBuf[2*i],16);
   }
   printf("%s\n",printBuf);
}
return;
}