hmac.cpp

// 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