//

// HmacSha1.c

//

// Copyright (c) Microsoft Corporation. Licensed under the MIT license.

//

#include "precomp.h"

//

// This implementation of HMAC uses extensive knowledge of the internal workings of the

// SHA1 implementation and uses internal routines. 

// This reduces the overhead per HMAC computation by up to 20%, which is significant

// enough to take on the added complexity.

//

#define ALG SHA1

#define Alg Sha1

#define SET_DATALENGTH( state, len )    {state.dataLengthL = len;}

#include "hmac_pattern.c"

#undef SET_DATALENGTH

#undef Alg

#undef ALG

const SYMCRYPT_MAC SymCryptHmacSha1Algorithm_default = {

    SymCryptHmacSha1ExpandKey,

    SymCryptHmacSha1Init,

    SymCryptHmacSha1Append,

    SymCryptHmacSha1Result,

    sizeof(SYMCRYPT_HMAC_SHA1_EXPANDED_KEY),

    sizeof(SYMCRYPT_HMAC_SHA1_STATE),

    SYMCRYPT_HMAC_SHA1_RESULT_SIZE,

    &SymCryptSha1Algorithm,

    SYMCRYPT_FIELD_OFFSET( SYMCRYPT_HMAC_SHA1_EXPANDED_KEY, outerState ),

};

const PCSYMCRYPT_MAC SymCryptHmacSha1Algorithm = &SymCryptHmacSha1Algorithm_default;

static const BYTE hmacSha1Kat[20] = {

    0x2a, 0x29, 0x85, 0x40, 0x23, 0xba, 0x2e, 0xf1,

    0x49, 0x0f, 0x8c, 0xd8, 0x97, 0xa8, 0xcc, 0x6b, 

    0x55, 0x7b, 0x2a, 0x12,

};

VOID

SYMCRYPT_CALL

SymCryptHmacSha1Selftest(void)

{

    SYMCRYPT_HMAC_SHA1_EXPANDED_KEY xKey;

    BYTE res[SYMCRYPT_HMAC_SHA1_RESULT_SIZE];

    SymCryptHmacSha1ExpandKey( &xKey, SymCryptTestKey32, 16 );

    SymCryptHmacSha1( &xKey, SymCryptTestMsg3, sizeof( SymCryptTestMsg3 ), res );

    SymCryptInjectError( res, sizeof( res ) );

    if( memcmp( res, hmacSha1Kat, sizeof( res ) ) != 0 ) 

    {

        SymCryptFatal( 'hSh1' );

    }

    //

    // Normally we would wipe the expanded key structure here,

    // but as this is a selftest with known data this is not needed.

    //

}