120 lines
2.6 KiB
C++
120 lines
2.6 KiB
C++
// hmac.h - written and placed in the public domain by Wei Dai
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#ifndef CRYPTOPP_HMAC_H
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#define CRYPTOPP_HMAC_H
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#include "seckey.h"
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#include "secblock.h"
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NAMESPACE_BEGIN(CryptoPP)
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template <class T>
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class HMAC_Base : public VariableKeyLength<16, 0, UINT_MAX>, public MessageAuthenticationCode
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{
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public:
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static std::string StaticAlgorithmName() {return std::string("HMAC(") + T::StaticAlgorithmName() + ")";}
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// put enums here for Metrowerks 4
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enum {DIGESTSIZE=T::DIGESTSIZE, BLOCKSIZE=T::BLOCKSIZE};
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HMAC_Base() : m_innerHashKeyed(false) {}
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void UncheckedSetKey(const byte *userKey, unsigned int keylength);
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void Restart();
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void Update(const byte *input, unsigned int length);
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void TruncatedFinal(byte *mac, unsigned int size);
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unsigned int DigestSize() const {return DIGESTSIZE;}
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private:
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void KeyInnerHash();
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enum {IPAD=0x36, OPAD=0x5c};
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FixedSizeSecBlock<byte, BLOCKSIZE> k_ipad, k_opad;
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FixedSizeSecBlock<byte, DIGESTSIZE> m_innerHash;
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T m_hash;
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bool m_innerHashKeyed;
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};
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//! <a href="http://www.weidai.com/scan-mirror/mac.html#HMAC">HMAC</a>
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/*! HMAC(K, text) = H(K XOR opad, H(K XOR ipad, text)) */
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template <class T>
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class HMAC : public MessageAuthenticationCodeTemplate<HMAC_Base<T> >
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{
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public:
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HMAC() {}
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HMAC(const byte *key, unsigned int length=HMAC_Base<T>::DEFAULT_KEYLENGTH)
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{SetKey(key, length);}
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};
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template <class T>
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void HMAC_Base<T>::UncheckedSetKey(const byte *userKey, unsigned int keylength)
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{
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AssertValidKeyLength(keylength);
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Restart();
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if (keylength <= T::BLOCKSIZE)
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memcpy(k_ipad, userKey, keylength);
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else
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{
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m_hash.CalculateDigest(k_ipad, userKey, keylength);
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keylength = T::DIGESTSIZE;
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}
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assert(keylength <= T::BLOCKSIZE);
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memset(k_ipad+keylength, 0, T::BLOCKSIZE-keylength);
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for (unsigned int i=0; i<T::BLOCKSIZE; i++)
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{
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k_opad[i] = k_ipad[i] ^ OPAD;
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k_ipad[i] ^= IPAD;
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}
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}
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template <class T>
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void HMAC_Base<T>::KeyInnerHash()
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{
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assert(!m_innerHashKeyed);
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m_hash.Update(k_ipad, T::BLOCKSIZE);
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m_innerHashKeyed = true;
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}
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template <class T>
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void HMAC_Base<T>::Restart()
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{
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if (m_innerHashKeyed)
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{
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m_hash.Restart();
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m_innerHashKeyed = false;
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}
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}
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template <class T>
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void HMAC_Base<T>::Update(const byte *input, unsigned int length)
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{
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if (!m_innerHashKeyed)
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KeyInnerHash();
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m_hash.Update(input, length);
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}
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template <class T>
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void HMAC_Base<T>::TruncatedFinal(byte *mac, unsigned int size)
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{
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ThrowIfInvalidTruncatedSize(size);
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if (!m_innerHashKeyed)
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KeyInnerHash();
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m_hash.Final(m_innerHash);
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m_hash.Update(k_opad, T::BLOCKSIZE);
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m_hash.Update(m_innerHash, DIGESTSIZE);
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m_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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