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#ifndef BITCOIN_CRYPTO_HKDF_SHA256_32_H
6#define BITCOIN_CRYPTO_HKDF_SHA256_32_H
7
8#include <cstddef>
9#include <string>
10
11/** A rfc5869 HKDF implementation with HMAC_SHA256 and fixed key output length of 32 bytes (L=32) */
12class CHKDF_HMAC_SHA256_L32
13{
14private:
15    unsigned char m_prk[32];
16    static constexpr size_t OUTPUT_SIZE{32};
17
18public:
19    CHKDF_HMAC_SHA256_L32(const unsigned char* ikm, size_t ikmlen, const std::string& salt);
20    void Expand32(const std::string& info, unsigned char hash[OUTPUT_SIZE]);
21};
22
23#endif // BITCOIN_CRYPTO_HKDF_SHA256_32_H
24