// hmac.cpp - originally 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)

  {

    // hmac.cpp:26:9: runtime error: null pointer passed as argument 2

    if (AccessIpad() && userKey && keylength)

      std::memcpy(AccessIpad(), userKey, keylength);

  }

  else

  {

    AccessHash().CalculateDigest(AccessIpad(), userKey, keylength);

    keylength = hash.DigestSize();

  }

  CRYPTOPP_ASSERT(keylength <= blockSize);

  std::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()

{

  CRYPTOPP_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