Initial revision

git-svn-id: svn://svn.code.sf.net/p/cryptopp/code/trunk/c5@2 57ff6487-cd31-0410-9ec3-f628ee90f5f0

1 files changed, 119 insertions, 0 deletions

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