QuickHash Library

API

SL_HMAC_Final

int SL_HASHCALL SL_HMAC_Final( void* pContext, void* pDest );

Return value

Nonzero if the function succeeds, otherwise 0. In particular, this function returns 0 when the context was improperly initialized.

Parameters

 pContext

    [in/out] Pointer to the context.

 pDest

    [out] Pointer to the memory buffer that will receive the HMAC.

Remarks

Call this function to retrieve the HMAC from the context pointed by pContext. The HMAC is retrieved in the memory buffer pointed by pDest. The size of the memory buffer pointed by pDest must be at least DIGESTSIZE bytes. DIGESTSIZE is a predefined constant that specifies the size of the HMAC for a specific hash algorithm. For example, you have to allocate at least SLC_RIPEMD160_DIGESTSIZE bytes for the memory buffer pointed by pDest if you need to calculate the HMAC using RIPEMD160 hash algorithm.

All supported hash algorithms with their corresponding DIGESTSIZEs are listed in Table1.

After the SL_HMAC_Final function is performed, the context is initialized for new calculations, as it would be called SL_HMAC_Init again.

Table1. Supported hash algorithms and their DIGESTSIZEs.

Example

#include <stdio.h>
#include <string.h>
#include <QuickHash.h>

#define BUFF_SIZE  1024

int main()
{
    FILE* file;
    
    unsigned char buff[ BUFF_SIZE ];
    char key[] = "File Password";

    unsigned char context[ SLC_HMAC_CONTEXTSIZE( SLC_RIPEMD160_CONTEXTSIZE, SLC_RIPEMD160_BLOCKSIZE ) ];
    unsigned char hmac[ SLC_RIPEMD160_DIGESTSIZE ]; 

    file = fopen( "c:\\test.txt", "rb" );

    if( file == NULL )
        return 1;

    /*****Initialize the context before calling Update, Final, or FinalHex****/

    SL_HMAC_Init( context, SLC_RIPEMD160_ALGID, key, strlen( key ) );

    /*****Calculate the HMAC by calling Update for each block of the file*****/

    while( !feof( file ) )
    {
        unsigned int nCount = fread( buff, sizeof( char ), BUFF_SIZE, file );
        SL_HMAC_Update( context, buff, nCount );
    }

    /*****Do final changes and get the RIPEMD160 HMAC*************************/

    SL_HMAC_Final( context, hmac );

    /*****Use the HMAC********************************************************/
    /*...*/

    fclose( file );

    return 0;
}

HMAC API Overview   |   HMAC Functions   |   Useful Links   |   HashCalc

See Also    SL_HMAC_FinalHex, SL_HMAC_Update, SL_HMAC_UpdateStr, SL_HMAC_Init, SL_HMAC_InitKeyStr