/*====================================================================*
 *
 *   Copyright (c) 2013 Qualcomm Atheros, Inc.
 *
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or
 *   without modification, are permitted (subject to the limitations
 *   in the disclaimer below) provided that the following conditions
 *   are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   * Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials
 *     provided with the distribution.
 *
 *   * Neither the name of Qualcomm Atheros nor the names of
 *     its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written
 *     permission.
 *
 *   NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE
 *   GRANTED BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE
 *   COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
 *   IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 *   PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
 *   OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 *   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *   LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 *   OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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 *--------------------------------------------------------------------*/

/*====================================================================*
 *
 *   void HPAVKeyNID (uint8_t NID [], const uint8_t NMK [], signed level);
 *
 *   HPAVKey.h
 *
 *   compute the HomePlugAV compliant Network Identification Key (NID)
 *   for a given Network Membership Key (NMK); return the key in buffer
 *   NID []; the key will be HPAVKEY_NID_LEN bytes as defined in
 *   HPAVKey.h;
 *
 *   unlike the NMK, the NID is 54-bits and includes a 2-bit security
 *   level; See the HomePlug AV Specification for more info;
 *
 *   hash the NMK then rehash the digest 4 times per HomePlug AV
 *   Specification; no salt is used;
 *
 *
 *   Contributor(s);
 *	Charles Maier
 *
 *--------------------------------------------------------------------*/

#ifndef HPAVKEYNID_SOURCE
#define HPAVKEYNID_SOURCE

#include <memory.h>

#include "../key/HPAVKey.h"
#include "../key/SHA256.h"

void HPAVKeyNID (uint8_t NID [], const uint8_t NMK [], uint8_t level)

{
	struct sha256 sha256;
	uint8_t digest [SHA256_DIGEST_LENGTH];
	unsigned rehash = 4;
	SHA256Reset (&sha256);
	SHA256Write (&sha256, NMK, HPAVKEY_NMK_LEN);
	SHA256Fetch (&sha256, digest);
	while (rehash--)
	{
		SHA256Reset (&sha256);
		SHA256Write (&sha256, digest, sizeof (digest));
		SHA256Fetch (&sha256, digest);
	}

#if 1

	level <<= 4;
	digest [HPAVKEY_NID_LEN - 1] >>= 4;
	digest [HPAVKEY_NID_LEN - 1] |= level;

#else

	digest [HPAVKEY_NID_LEN - 1] &= ~0xC0;
	digest [HPAVKEY_NID_LEN - 1] |= level << 6;

#endif

	memcpy (NID, digest, HPAVKEY_NID_LEN);
	return;
}


#endif