MD5 파일 변조 검사 관련 소스 (리눅스/Windows)

 

리눅스용 소스
Linux 2.4.x 운영체제에서 openssl 에서 제공하는 MD5 함수를 이용해서 코딩되었습니다.
컴파일 방법 : $gcc -o getmd5 getmd5.c -lssl -lcrypto

#include <openssl/md5.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>

int main(int argc, char **argv)
{
    MD5_CTX lctx;
    unsigned char digest[16];
    char md5msg[40];
    int i;
    int fd;
    struct stat status;
    char *file_name = argv[1];
    char *data;

    MD5_Init(&lctx);

    fd = open(file_name, O_RDONLY);
    if (fd < 0)
    {
        perror("error : ");
        exit(0);
    }
    fstat(fd, &status);

    data = (char *)malloc(status.st_size);
    read (fd, data, status.st_size);

    MD5_Update(&lctx, data, status.st_size);
    MD5_Final(digest, &lctx);

    for (i = 0; i < sizeof(digest); ++i)
    {
        sprintf(md5msg+(i*2), "%02x", digest[i]);
    }
    printf ("%s\n", md5msg);
    free(data);
}



아래는 윈도용 소스 입니다.

사용법:

Cmd5Capi md5Capi;

CString passwdStr;
totalStr = md5Capi.Digest(passwdStr);

 

code:--------------------------------------------------------------------------------// md5Capi.h: interface for the Cmd5Capi class.
//
//////////////////////////////////////////////////////////////////////

#if  !defined(AFX_MD5CAPI_H__438D2BEF_6F1B_4C5C_830F_0E
7B6D1FD7E2__INCLUDED_)
#define  AFX_MD5CAPI_H__438D2BEF_6F1B_4C5C_830F_0E7B6D1FD7E
2__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include <wincrypt.h> // Cryptographic API Prototypes and Definitions

class Cmd5Capi 
{
public:
 CString &Digest(CString & csBuffer);
 CString &GetDigest(void);

 Cmd5Capi(CString & csBuffer);
 Cmd5Capi();
 virtual ~Cmd5Capi();
 CString csDigest;
};

 

#endif //  !defined(AFX_MD5CAPI_H__438D2BEF_6F1B_4C5C_830F_0E
7B6D1FD7E2__INCLUDED_)
--------------------------------------------------------------------------------

 

code:--------------------------------------------------------------------------------
//////////////////////////////////////////////////////////////////////
// md5Capi.cpp: implementation of the Cmd5Capi class.
// Calcule MD5 Digest using the WIN Crypto API.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "md5Capi.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

Cmd5Capi::Cmd5Capi()
{
 csDigest.Empty();
}

Cmd5Capi::Cmd5Capi(CString & csBuffer)
{
 Digest(csBuffer);
}

 

Cmd5Capi::~Cmd5Capi()
{

}

CString &Cmd5Capi::GetDigest(void)
{
 return csDigest;

}

CString &Cmd5Capi::Digest(CString & csBuffer)
{
    HCRYPTPROV hCryptProv;
    HCRYPTHASH hHash;
    BYTE bHash[0x7f];
    DWORD dwHashLen= 16; // The MD5 algorithm always returns 16 bytes.
    DWORD cbContent= csBuffer.GetLength();
    BYTE* pbContent= (BYTE*)csBuffer.GetBuffer(cbContent);

    if(CryptAcquireContext(&hCryptProv,
  NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_MACHINE_KEYSET))
 {

  if(CryptCreateHash(hCryptProv,
   CALG_MD5, // algorithm identifier definitions see: wincrypt.h
   0, 0, &hHash))
  {
   if(CryptHashData(hHash, pbContent, cbContent, 0))
   {

    if(CryptGetHashParam(hHash, HP_HASHVAL, bHash, &dwHashLen, 0))
    {
     // Make a string version of the numeric digest value
     csDigest.Empty();
     CString tmp;
       for (int i = 0; i<16; i++)
       {
      tmp.Format("%02x", bHash[i]);
      csDigest+=tmp;
       }

    }
    else csDigest=_T("Error getting hash param");

   }
   else csDigest=_T("Error hashing data");
  }
  else csDigest=_T("Error creating hash");

    }
    else csDigest=_T("Error acquiring context");

    CryptDestroyHash(hHash);
    CryptReleaseContext(hCryptProv, 0);
 csBuffer.ReleaseBuffer();
    return csDigest;

}