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