1// Copyright (c) 2018-present The Bitcoin Core developers
2// Distributed under the MIT software license, see the accompanying
3// file COPYING or http://www.opensource.org/licenses/mit-license.php.
4
5#include <crypto/hkdf_sha256_32.h>
6
7#include <crypto/hmac_sha256.h>
8
9#include <cassert>
10
11CHKDF_HMAC_SHA256_L32::CHKDF_HMAC_SHA256_L32(const unsigned char* ikm, size_t ikmlen, const std::string& salt)
12{
13    CHMAC_SHA256((const unsigned char*)salt.data(), salt.size()).Write(ikm, ikmlen).Finalize(m_prk);
14}
15
16void CHKDF_HMAC_SHA256_L32::Expand32(const std::string& info, unsigned char hash[OUTPUT_SIZE])
17{
18    // expand a 32byte key (single round)
19    assert(info.size() <= 128);
20    static const unsigned char one[1] = {1};
21    CHMAC_SHA256(m_prk, 32).Write((const unsigned char*)info.data(), info.size()).Write(one, 1).Finalize(hash);
22}
23