// hmac.cpp - written and placed in the public domain by Wei Dai #include "pch.h" #ifndef CRYPTOPP_IMPORTS #include "hmac.h" NAMESPACE_BEGIN(CryptoPP) void HMAC_Base::UncheckedSetKey(const byte *userKey, unsigned int keylength, const NameValuePairs &) { AssertValidKeyLength(keylength); Restart(); HashTransformation &hash = AccessHash(); unsigned int blockSize = hash.BlockSize(); if (!blockSize) throw InvalidArgument("HMAC: can only be used with a block-based hash function"); m_buf.resize(2*AccessHash().BlockSize() + AccessHash().DigestSize()); if (keylength <= blockSize) memcpy(AccessIpad(), userKey, keylength); else { AccessHash().CalculateDigest(AccessIpad(), userKey, keylength); keylength = hash.DigestSize(); } assert(keylength <= blockSize); memset(AccessIpad()+keylength, 0, blockSize-keylength); for (unsigned int i=0; i<blockSize; i++) { AccessOpad()[i] = AccessIpad()[i] ^ 0x5c; AccessIpad()[i] ^= 0x36; } } void HMAC_Base::KeyInnerHash() { assert(!m_innerHashKeyed); HashTransformation &hash = AccessHash(); hash.Update(AccessIpad(), hash.BlockSize()); m_innerHashKeyed = true; } void HMAC_Base::Restart() { if (m_innerHashKeyed) { AccessHash().Restart(); m_innerHashKeyed = false; } } void HMAC_Base::Update(const byte *input, size_t length) { if (!m_innerHashKeyed) KeyInnerHash(); AccessHash().Update(input, length); } void HMAC_Base::TruncatedFinal(byte *mac, size_t size) { ThrowIfInvalidTruncatedSize(size); HashTransformation &hash = AccessHash(); if (!m_innerHashKeyed) KeyInnerHash(); hash.Final(AccessInnerHash()); hash.Update(AccessOpad(), hash.BlockSize()); hash.Update(AccessInnerHash(), hash.DigestSize()); hash.TruncatedFinal(mac, size); m_innerHashKeyed = false; } NAMESPACE_END #endif