Thread: md5 hash a file

Hi All,

Is there a win32 library that I can use to generate an md5 of a file?

I only get .NET results when searching msdn.

Thanks for any help,

rotis23

Try searching for md5.c

Here
http://www.l2tpd.org/cxref/md5.c.src.html

I've always used the md5 code at http://sourceforge.net/project/showf...group_id=42360

It is just two files (a .c and a .h), and very simple to use.

Thanks guys - found win32 specifc info here:

http://msdn.microsoft.com/library/de...le_content.asp

I wanted to post my code when I saw the thread title. I seem to have been beaten to the punch. Oh well, I'll post it anyway.

Code:

#include <windows.h>
#include <wincrypt.h>
#pragma comment(lib, "advapi32.lib")

/*
 * Creates a hexadecimal hash string from input data.
 * ALG_ID can be one of CALG_MD2, CALG_MD4, CALG_MD5 or CALG_SHA1.
 * SHA1 algorithm is strongest, while MD2 and MD4 should be avoided.
 * MD algorithms require a 33 character output buffer. SHA1 requires 41 characters.
 * Returns TRUE on success, FALSE on failure.
 */
BOOL HashData(LPTSTR szOut, DWORD cchOut, LPCBYTE lpIn, DWORD cbIn, ALG_ID hash_algorithm)
{
	HCRYPTPROV hProv      = 0;
	HCRYPTHASH hHash      = 0;
	BYTE       raw[64];
	DWORD      raw_len    = sizeof(raw);
	BOOL       bResult    = FALSE;
	UINT       i;

	if(CryptAcquireContext(&hProv, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT) &&
	   CryptCreateHash(hProv, hash_algorithm, 0, 0, &hHash) &&
	   CryptHashData(hHash, lpIn, cbIn, 0) &&
	   CryptGetHashParam(hHash, HP_HASHVAL, raw, &raw_len, 0) &&
	   (raw_len * 2) + 1 <= cchOut)
	{
		for (i = 0;i < raw_len;i++)
		{
			wsprintf(&szOut[i * 2], TEXT("%02.2x"), raw[i]);
		}

		bResult = TRUE;
	}

	if (hHash) CryptDestroyHash(hHash);
	if (hProv) CryptReleaseContext(hProv, 0);

	return bResult;
}


#if 1
#include <stdio.h>

int main(void)
{
	TCHAR szHash[64];
	char * test = "Hello, this is a test";

	printf("Input: %s\n", test);

	if (HashData(szHash, 33, test, strlen(test), CALG_MD5))
		printf("MD5: %s\n", szHash);

	if (HashData(szHash, 33, test, strlen(test), CALG_MD2))
		printf("MD2: %s\n", szHash);

	if (HashData(szHash, 33, test, strlen(test), CALG_MD4))
		printf("MD4: %s\n", szHash);

	if (HashData(szHash, 41, test, strlen(test), CALG_SHA1))
		printf("SHA1: %s\n", szHash);

	getchar();
	return 0;
}
#endif


/// ===================================================================
/// Hashing in chunks.

HCRYPTHASH HashInit(HCRYPTPROV hCryptProvider, ALG_ID hash_algorithm)
{
	HCRYPTHASH hHash = 0;
	CryptCreateHash(hCryptProvider, hash_algorithm, 0, 0, &hHash);
	return hHash;
}

BOOL HashUpdate(HCRYPTHASH hHash, LPCBYTE lpData, DWORD cbData)
{
	return CryptHashData(hHash, lpData, cbData, 0);
}

BOOL HashFinal(HCRYPTHASH hHash, LPTSTR szOut, DWORD cchOut)
{
	BYTE       raw[64];
	DWORD      raw_len    = sizeof(raw);
	BOOL       bResult    = FALSE;
	UINT       i;

	if (CryptGetHashParam(hHash, HP_HASHVAL, raw, &raw_len, 0) &&
	    (raw_len * 2) + 1 <= cchOut)
	{
		for (i = 0;i < raw_len;i++)
		{
			wsprintf(&szOut[i * 2], TEXT("%02.2x"), raw[i]);
		}

		bResult = TRUE;
	}

	if (hHash) CryptDestroyHash(hHash);

	return bResult;
}


#if 0
#include <stdio.h>

int main(void)
{
	HCRYPTPROV hProv      = 0;
	HCRYPTHASH hHash      = 0;
	TCHAR szHash[64];

	CryptAcquireContext(&hProv, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT);

	hHash = HashInit(hProv, CALG_MD5);
	HashUpdate(hHash, "abcd", strlen("abcd"));
	HashUpdate(hHash, "efgh", strlen("efgh"));
	HashFinal(hHash, szHash, 33);
	printf("MD5: %s\n", szHash);

	hHash = HashInit(hProv, CALG_SHA1);
	HashUpdate(hHash, "abcd", strlen("abcd"));
	HashUpdate(hHash, "efgh", strlen("efgh"));
	HashFinal(hHash, szHash, 41);
	printf("SHA1: %s\n", szHash);

	CryptReleaseContext(hProv, 0);
	getchar();
	return 0;
}
#endif

I have to comment on this, from the Microsoft sample code:

Code:

    CHAR rgbDigits[] = "0123456789abcdef";

    printf("%c%c", rgbDigits[rgbHash[i] >> 4],
            rgbDigits[rgbHash[i] & 0xf]);

That is one creative way of outputting hexadecimal!