Проверка файла на контрольную сумму MD5

if(md5(files.exe) == "8b13d760f3dddb0d630cab850747317e")
.....

//#include "md5.h"
#include <WINDEF.H>
#include <stdio.h>
#include <windows.h>
 
#ifdef __alpha
typedef unsigned int UINT4;
#else
typedef unsigned long int UINT4;
#endif
 
#define MD5_INIT_STATE_0 0x67452301
#define MD5_INIT_STATE_1 0xefcdab89
#define MD5_INIT_STATE_2 0x98badcfe
#define MD5_INIT_STATE_3 0x10325476
 
void MD5Init(void);
void MD5Update(unsigned char *bug, unsigned int len);
void MD5Final(char* cReturnStr);
void Transform(UINT4 *buf, UINT4 *in);
 
BYTE  m_lpszBuffer[64];
ULONG m_nCount[2];
ULONG m_lMD5[4];
 
static unsigned char PADDING[64] = {
 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
 
#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 ByteToDWord(DWORD* Output, ULONG* Input, UINT nLength){
UINT i=0;
UINT j=0;
for (; j < nLength; i++, j += 4)
{
 Output[i] = (ULONG)Input[j]   | 
    (ULONG)Input[j+1] << 8 | 
    (ULONG)Input[j+2] << 16 | 
    (ULONG)Input[j+3] << 24;
}
}
 
void DWordToByte(unsigned char* Output, DWORD* Input, UINT nLength ){
UINT i = 0;
UINT j = 0;
for (; j < nLength; i++, j += 4) 
{
 Output[j] =   (UCHAR)(Input[i] & 0xff);
 Output[j+1] = (UCHAR)((Input[i] >> 8) & 0xff);
 Output[j+2] = (UCHAR)((Input[i] >> 16) & 0xff);
 Output[j+3] = (UCHAR)((Input[i] >> 24) & 0xff);
}
}
 
void MD5Init (void)
{
 memset(m_lpszBuffer, 0, 64 );
 m_nCount[0] = m_nCount[1] = 0;
 
m_lMD5[0] = MD5_INIT_STATE_0;
m_lMD5[1] = MD5_INIT_STATE_1;
m_lMD5[2] = MD5_INIT_STATE_2;
m_lMD5[3] = MD5_INIT_STATE_3;
}
 
void MD5Update (unsigned char *inBuf, unsigned int inLen)
{
 register int i, ii;
 int mdi;
 UINT4 in[16];
 
 mdi = (int)((m_nCount[0] >> 3) & 0x3F);
 
 if ((m_nCount[0] + ((UINT4)inLen << 3)) < m_nCount[0])
   m_nCount[1]++;
 m_nCount[0] += ((UINT4)inLen << 3);
 m_nCount[1] += ((UINT4)inLen >> 29);
 
 while (inLen--) {
   m_lpszBuffer[mdi++] = *inBuf++;
 
   if (mdi == 0x40) {
     for (i = 0, ii = 0; i < 16; i++, ii += 4)
       in[i] = (((UINT4)m_lpszBuffer[ii+3]) << 24) |
               (((UINT4)m_lpszBuffer[ii+2]) << 16) |
               (((UINT4)m_lpszBuffer[ii+1]) << 8) |
               ((UINT4)m_lpszBuffer[ii]);
     Transform (m_lMD5, in);
     mdi = 0;
   }
 }
}
 
void MD5Final (char* cReturnStr)
{
unsigned char bits[8];
int nIndex;
unsigned int nPadLen;
const int nMD5Size = 16;
 unsigned char lpszMD5[16];
char temp[2];
int i;
 
cReturnStr[0]='\0';
 
DWordToByte( bits, m_nCount, 8 );
 
nIndex = (int)((m_nCount[0] >> 3) & 0x3f);
nPadLen = (nIndex < 56) ? (56 - nIndex) : (120 - nIndex);
MD5Update (PADDING, nPadLen);
 
MD5Update (bits, 8);
 
DWordToByte( lpszMD5, m_lMD5, nMD5Size );
 
for (i=0; i < nMD5Size; i++) 
{
 
 if (lpszMD5[i] == 0) {
  temp[0] = '0';
  temp[1]='0';
 }
 else if (lpszMD5[i] <= 15)  {
     sprintf(temp,"0%x",lpszMD5[i]);
 }
 else {
     sprintf(temp,"%x",lpszMD5[i]);
 }
   strcat(cReturnStr,temp);
}
lpszMD5[0]='\0';
}
 
void Transform(register UINT4 *buf,register UINT4 *in)
{
 register UINT4 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
 
#define S11 7
#define S12 12
#define S13 17
#define S14 22
 FF ( a, b, c, d, in[ 0], S11, 0xD76AA478L); 
 FF ( d, a, b, c, in[ 1], S12, 0xE8C7B756L); 
 FF ( c, d, a, b, in[ 2], S13, 0x242070DBL); 
 FF ( b, c, d, a, in[ 3], S14, 0xC1BDCEEEL); 
 FF ( a, b, c, d, in[ 4], S11, 0xF57C0FAFL); 
 FF ( d, a, b, c, in[ 5], S12, 0x4787C62AL); 
 FF ( c, d, a, b, in[ 6], S13, 0xA8304613L); 
 FF ( b, c, d, a, in[ 7], S14, 0xFD469501L); 
 FF ( a, b, c, d, in[ 8], S11, 0x698098D8L); 
 FF ( d, a, b, c, in[ 9], S12, 0x8B44F7AFL); 
 FF ( c, d, a, b, in[10], S13, 0xFFFF5BB1L); 
 FF ( b, c, d, a, in[11], S14, 0x895CD7BEL); 
 FF ( a, b, c, d, in[12], S11, 0x6B901122L); 
 FF ( d, a, b, c, in[13], S12, 0xFD987193L); 
 FF ( c, d, a, b, in[14], S13, 0xA679438EL); 
 FF ( b, c, d, a, in[15], S14, 0x49B40821L); 
 
#define S21 5
#define S22 9
#define S23 14
#define S24 20
 GG ( a, b, c, d, in[ 1], S21, 0xF61E2562L); 
 GG ( d, a, b, c, in[ 6], S22, 0xC040B340L); 
 GG ( c, d, a, b, in[11], S23, 0x265E5A51L); 
 GG ( b, c, d, a, in[ 0], S24, 0xE9B6C7AAL); 
 GG ( a, b, c, d, in[ 5], S21, 0xD62F105DL); 
 GG ( d, a, b, c, in[10], S22, 0x02441453L); 
 GG ( c, d, a, b, in[15], S23, 0xD8A1E681L); 
 GG ( b, c, d, a, in[ 4], S24, 0xE7D3FBC8L); 
 GG ( a, b, c, d, in[ 9], S21, 0x21E1CDE6L); 
 GG ( d, a, b, c, in[14], S22, 0xC33707D6L); 
 GG ( c, d, a, b, in[ 3], S23, 0xF4D50D87L); 
 GG ( b, c, d, a, in[ 8], S24, 0x455A14EDL); 
 GG ( a, b, c, d, in[13], S21, 0xA9E3E905L); 
 GG ( d, a, b, c, in[ 2], S22, 0xFCEFA3F8L); 
 GG ( c, d, a, b, in[ 7], S23, 0x676F02D9L); 
 GG ( b, c, d, a, in[12], S24, 0x8D2A4C8AL); 
 
#define S31 4
#define S32 11
#define S33 16
#define S34 23
 HH ( a, b, c, d, in[ 5], S31, 0xFFFA3942L); 
 HH ( d, a, b, c, in[ 8], S32, 0x8771F681L); 
 HH ( c, d, a, b, in[11], S33, 0x6D9D6122L); 
 HH ( b, c, d, a, in[14], S34, 0xFDE5380CL); 
 HH ( a, b, c, d, in[ 1], S31, 0xA4BEEA44L);
 HH ( d, a, b, c, in[ 4], S32, 0x4BDECFA9L); 
 HH ( c, d, a, b, in[ 7], S33, 0xF6BB4B60L); 
 HH ( b, c, d, a, in[10], S34, 0xBEBFBC70L); 
 HH ( a, b, c, d, in[13], S31, 0x289B7EC6L); 
 HH ( d, a, b, c, in[ 0], S32, 0xEAA127FAL); 
 HH ( c, d, a, b, in[ 3], S33, 0xD4EF3085L); 
 HH ( b, c, d, a, in[ 6], S34, 0x04881D05L);
 HH ( a, b, c, d, in[ 9], S31, 0xD9D4D039L); 
 HH ( d, a, b, c, in[12], S32, 0xE6DB99E5L); 
 HH ( c, d, a, b, in[15], S33, 0x1FA27CF8L); 
 HH ( b, c, d, a, in[ 2], S34, 0xC4AC5665L); 
 
#define S41 6
#define S42 10
#define S43 15
#define S44 21
 II ( a, b, c, d, in[ 0], S41, 0xF4292244L); 
 II ( d, a, b, c, in[ 7], S42, 0x432AFF97L); 
 II ( c, d, a, b, in[14], S43, 0xAB9423A7L); 
 II ( b, c, d, a, in[ 5], S44, 0xFC93A039L); 
 II ( a, b, c, d, in[12], S41, 0x655B59C3L); 
 II ( d, a, b, c, in[ 3], S42, 0x8F0CCC92L); 
 II ( c, d, a, b, in[10], S43, 0xFFEFF47DL); 
 II ( b, c, d, a, in[ 1], S44, 0x85845DD1L); 
 II ( a, b, c, d, in[ 8], S41, 0x6FA87E4FL); 
 II ( d, a, b, c, in[15], S42, 0xFE2CE6E0L); 
 II ( c, d, a, b, in[ 6], S43, 0xA3014314L); 
 II ( b, c, d, a, in[13], S44, 0x4E0811A1L); 
 II ( a, b, c, d, in[ 4], S41, 0xF7537E82L); 
 II ( d, a, b, c, in[11], S42, 0xBD3AF235L); 
 II ( c, d, a, b, in[ 2], S43, 0x2AD7D2BBL); 
 II ( b, c, d, a, in[ 9], S44, 0xEB86D391L); 
 
 buf[0] += a;
 buf[1] += b;
 buf[2] += c;
 buf[3] += d;
}
 
void GetMD5(char* pBuf, UINT nLength,char* cReturnStr){
MD5Init();
MD5Update((unsigned char*)pBuf, nLength);
MD5Final(cReturnStr);
}
 
int main () {
  
  //Находим md5 строки
  char src []= "01234";
  char rez [50];
  GetMD5(src, 5, rez);
  printf (rez);
  
  //////////////////////////////////////////////////////////
  
  //Находим md5 файла
  char file_name []= "main.cpp";
  
  HANDLE  hFile = CreateFile(file_name, GENERIC_READ | GENERIC_WRITE,
    0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
 
 
  HANDLE  hMapping = CreateFileMapping(
        hFile,     // дескриптор открытого файла
        NULL,      // атрибуты защиты по умолчанию
        PAGE_READWRITE,  // режим доступа
        0, 0,      // размер объекта отображения равен размеру файла
        NULL);     // имя не используем
 
  // создаем вид файла
  char* ptr = (char*)MapViewOfFile(
      hMapping,    // дескриптор объекта отображения
      FILE_MAP_WRITE,    // режим доступа к виду
      0, 0,        // отображаем файл с начала
      0);          // отображаем весь файл
 
  
  long int Razmer_Faila= (long int)GetFileSize(hFile, 0);
 
  printf ("\n%d\n", Razmer_Faila);
  GetMD5(ptr, Razmer_Faila, rez);
  printf (rez);
 
  UnmapViewOfFile(ptr); 
  CloseHandle(hMapping);
  CloseHandle(hFile);  
  
  getchar ();
}