Need Help Getting SHA1 value of File

I'm trying to write a routine to get the SAH1 hash value of graphics and video files. Can find lots of docs on how to hash a password but none on how to
get the hash of a file. It appears that GetHashFromFile is what I need to use
but I could use some example code. Am using VB.Net 2003
Thanks,
Dave

I have a code in C

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

#define BUFSIZE 1024
#define MD5LEN 16

DWORD main(int argc, char *argv[])
{
DWORD dwStatus = 0;
BOOL bResult = FALSE;
HCRYPTPROV hProv = 0;
HCRYPTHASH hHash = 0;
HANDLE hFile = NULL;
BYTE rgbFile[BUFSIZE];
DWORD cbRead = 0;
BYTE rgbHash[MD5LEN];
DWORD cbHash = 0;
CHAR rgbDigits[] = "0123456789abcdef";

//Logic to check usage goes here.

hFile = CreateFile(argv[1],
GENERIC_READ,
FILE_SHARE_READ,
NULL,
OPEN_EXISTING,
FILE_FLAG_SEQUENTIAL_SCAN,
NULL);

if (INVALID_HANDLE_VALUE == hFile)
{
dwStatus = GetLastError();
printf("Error opening file %s\nError: %d\n", argv[1], dwStatus);
return dwStatus;
}

//Get handle to the crypto provider
if (!CryptAcquireContext(&hProv,
NULL,
NULL,
PROV_RSA_FULL,
CRYPT_VERIFYCONTEXT))
{
dwStatus = GetLastError();
printf("CryptAcquireContext failed: %d\n", dwStatus);
CloseHandle(hFile);
return dwStatus;
}

if (!CryptCreateHash(hProv, CALG_MD5, 0, 0, &hHash))
{
dwStatus = GetLastError();
printf("CryptAcquireContext failed: %d\n", dwStatus);
CloseHandle(hFile);
CryptReleaseContext(hProv, 0);
return dwStatus;
}

while (bResult = ReadFile(hFile, rgbFile, BUFSIZE, &cbRead, NULL))
{
if (0 == cbRead)
{
break;
}

if (!CryptHashData(hHash, rgbFile, cbRead, 0))
{
dwStatus = GetLastError();
printf("CryptHashData failed: %d\n", dwStatus);
CryptReleaseContext(hProv, 0);
CryptDestroyHash(hHash);
CloseHandle(hFile);
return dwStatus;
}
}

if (!bResult)
{
dwStatus = GetLastError();
printf("ReadFile failed: %d\n", dwStatus);
CryptReleaseContext(hProv, 0);
CryptDestroyHash(hHash);
CloseHandle(hFile);
return dwStatus;
}

cbHash = MD5LEN;
if (CryptGetHashParam(hHash, HP_HASHVAL, rgbHash, &cbHash, 0))
{
printf("MD5 hash of file %s is: ", argv[1]);
for (DWORD i = 0; i < cbHash; i++)
{
printf("%c%c", rgbDigits[rgbHash[i] >> 4],
rgbDigits[rgbHash[i] & 0xf]);
}
printf("\n");
}
else
{
dwStatus = GetLastError();
printf("CryptGetHashParam failed: %d\n", dwStatus);
}

CryptDestroyHash(hHash);
CryptReleaseContext(hProv, 0);
CloseHandle(hFile);

return dwStatus;

C code doesn't help me, don't understand it :(
I was hoping that getting the hash value of a file would be more common
nowadays!
Thanks though,
Dave

Here you go. Takes a file and generates a SHA1 hash for it. :D

VB Code:

Dim f As New System.IO.FileStream([b]FILENAME[/b], IO.FileMode.Open)
Dim sha As New System.Security.Cryptography.SHA1CryptoServiceProvider
Dim hash As Array
Dim shaHash as String
Dim sb As New System.Text.StringBuilder
 
sha.ComputeHash(f)
hash = sha.Hash
For Each hashByte As Byte In hash
    sb.Append(String.Format("{0:X1}", hashByte))
Next
shaHash = sb.ToString
f.Close()