// Copyright (c) 2014-present The Bitcoin Core developers

// Distributed under the MIT software license, see the accompanying

// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <crypto/hmac_sha256.h>

#include <crypto/sha256.h>

#include <support/cleanse.h>

#include <cstring>

CHMAC_SHA256::CHMAC_SHA256(const unsigned char* key, size_t keylen)

{

    unsigned char rkey[64];

    if (keylen <= 64) {

        memcpy(rkey, key, keylen);

        memset(rkey + keylen, 0, 64 - keylen);

    } else {

        CSHA256().Write(key, keylen).Finalize(rkey);

        memset(rkey + 32, 0, 32);

    }

    for (int n = 0; n < 64; n++)

        rkey[n] ^= 0x5c;

    outer.Write(rkey, 64);

    for (int n = 0; n < 64; n++)

        rkey[n] ^= 0x5c ^ 0x36;

    inner.Write(rkey, 64);

    memory_cleanse(rkey, sizeof(rkey));

}

void CHMAC_SHA256::Finalize(unsigned char hash[OUTPUT_SIZE])

{

    unsigned char temp[32];

    inner.Finalize(temp);

    outer.Write(temp, 32).Finalize(hash);

    memory_cleanse(temp, sizeof(temp));

}