/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * (c) ZeroTier, Inc.
 * https://www.zerotier.com/
 */

#ifndef ZT_SHA512_HPP
#define ZT_SHA512_HPP

#include "Constants.hpp"

#ifdef __APPLE__
#include <CommonCrypto/CommonDigest.h>
#endif

#define ZT_SHA512_DIGEST_SIZE 64
#define ZT_SHA384_DIGEST_SIZE 48
#define ZT_SHA512_BLOCK_SIZE  128
#define ZT_SHA384_BLOCK_SIZE  128

#define ZT_HMACSHA384_LEN 48

namespace ZeroTier {

// SHA384 and SHA512 are actually in the standard libraries on MacOS and iOS
#ifdef __APPLE__
#define ZT_HAVE_NATIVE_SHA512 1
static ZT_INLINE void SHA512(void* digest, const void* data, unsigned int len)
{
	CC_SHA512_CTX ctx;
	CC_SHA512_Init(&ctx);
	CC_SHA512_Update(&ctx, data, len);
	CC_SHA512_Final(reinterpret_cast<unsigned char*>(digest), &ctx);
}
static ZT_INLINE void SHA384(void* digest, const void* data, unsigned int len)
{
	CC_SHA512_CTX ctx;
	CC_SHA384_Init(&ctx);
	CC_SHA384_Update(&ctx, data, len);
	CC_SHA384_Final(reinterpret_cast<unsigned char*>(digest), &ctx);
}
static ZT_INLINE void SHA384(void* digest, const void* data0, unsigned int len0, const void* data1, unsigned int len1)
{
	CC_SHA512_CTX ctx;
	CC_SHA384_Init(&ctx);
	CC_SHA384_Update(&ctx, data0, len0);
	CC_SHA384_Update(&ctx, data1, len1);
	CC_SHA384_Final(reinterpret_cast<unsigned char*>(digest), &ctx);
}
#endif

#ifndef ZT_HAVE_NATIVE_SHA512
void SHA512(void* digest, const void* data, unsigned int len);
void SHA384(void* digest, const void* data, unsigned int len);
void SHA384(void* digest, const void* data0, unsigned int len0, const void* data1, unsigned int len1);
#endif

/**
 * Compute HMAC SHA-384 using a 256-bit key
 *
 * @param key Secret key
 * @param msg Message to HMAC
 * @param msglen Length of message
 * @param mac Buffer to fill with result
 */
void HMACSHA384(const uint8_t key[ZT_SYMMETRIC_KEY_SIZE], const void* msg, unsigned int msglen, uint8_t mac[48]);

/**
 * Compute KBKDF (key-based key derivation function) using HMAC-SHA-384 as a PRF
 *
 * @param key Source master key
 * @param label A label indicating the key's purpose in the ZeroTier system
 * @param context An arbitrary "context" or zero if not applicable
 * @param iter Key iteration for generation of multiple keys for the same label/context
 * @param out Output to receive derived key
 */
void KBKDFHMACSHA384(const uint8_t key[ZT_SYMMETRIC_KEY_SIZE], char label, char context, uint32_t iter, uint8_t out[ZT_SYMMETRIC_KEY_SIZE]);

}	// namespace ZeroTier

#endif