From 551d489416339dae8f9d896013cd060a21406e2b Mon Sep 17 00:00:00 2001 From: Jonas Schnelli Date: Fri, 24 Aug 2018 11:10:43 +0200 Subject: Add HKDF HMAC_SHA256 L=32 implementations --- src/crypto/hkdf_sha256_32.cpp | 21 +++++++++++++++++++++ src/crypto/hkdf_sha256_32.h | 25 +++++++++++++++++++++++++ 2 files changed, 46 insertions(+) create mode 100644 src/crypto/hkdf_sha256_32.cpp create mode 100644 src/crypto/hkdf_sha256_32.h (limited to 'src/crypto') diff --git a/src/crypto/hkdf_sha256_32.cpp b/src/crypto/hkdf_sha256_32.cpp new file mode 100644 index 0000000000..9cea5995ec --- /dev/null +++ b/src/crypto/hkdf_sha256_32.cpp @@ -0,0 +1,21 @@ +// Copyright (c) 2018 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 + +#include +#include + +CHKDF_HMAC_SHA256_L32::CHKDF_HMAC_SHA256_L32(const unsigned char* ikm, size_t ikmlen, const std::string& salt) +{ + CHMAC_SHA256((const unsigned char*)salt.c_str(), salt.size()).Write(ikm, ikmlen).Finalize(m_prk); +} + +void CHKDF_HMAC_SHA256_L32::Expand32(const std::string& info, unsigned char hash[OUTPUT_SIZE]) +{ + // expand a 32byte key (single round) + assert(info.size() <= 128); + static const unsigned char one[1] = {1}; + CHMAC_SHA256(m_prk, 32).Write((const unsigned char*)info.data(), info.size()).Write(one, 1).Finalize(hash); +} diff --git a/src/crypto/hkdf_sha256_32.h b/src/crypto/hkdf_sha256_32.h new file mode 100644 index 0000000000..fa1e42aec1 --- /dev/null +++ b/src/crypto/hkdf_sha256_32.h @@ -0,0 +1,25 @@ +// Copyright (c) 2018 The Bitcoin Core developers +// Distributed under the MIT software license, see the accompanying +// file COPYING or http://www.opensource.org/licenses/mit-license.php. + +#ifndef BITCOIN_CRYPTO_HKDF_SHA256_32_H +#define BITCOIN_CRYPTO_HKDF_SHA256_32_H + +#include + +#include +#include + +/** A rfc5869 HKDF implementation with HMAC_SHA256 and fixed key output length of 32 bytes (L=32) */ +class CHKDF_HMAC_SHA256_L32 +{ +private: + unsigned char m_prk[32]; + static const size_t OUTPUT_SIZE = 32; + +public: + CHKDF_HMAC_SHA256_L32(const unsigned char* ikm, size_t ikmlen, const std::string& salt); + void Expand32(const std::string& info, unsigned char hash[OUTPUT_SIZE]); +}; + +#endif // BITCOIN_CRYPTO_HKDF_SHA256_32_H -- cgit v1.2.3