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authorAlexander Harkness <bearbin@gmail.com>2013-11-24 15:21:13 +0100
committerAlexander Harkness <bearbin@gmail.com>2013-11-24 15:21:13 +0100
commit3438e5d3ddf8444f0e31009ffbe8237ef3752c22 (patch)
tree7c2f76d5e9281c130e60fb932c4dda89a49863b6 /lib/cryptopp/dmac.h
parentMoved source to src (diff)
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Diffstat (limited to 'lib/cryptopp/dmac.h')
-rw-r--r--lib/cryptopp/dmac.h93
1 files changed, 93 insertions, 0 deletions
diff --git a/lib/cryptopp/dmac.h b/lib/cryptopp/dmac.h
new file mode 100644
index 000000000..80b54ac2f
--- /dev/null
+++ b/lib/cryptopp/dmac.h
@@ -0,0 +1,93 @@
+#ifndef CRYPTOPP_DMAC_H
+#define CRYPTOPP_DMAC_H
+
+#include "cbcmac.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+//! _
+template <class T>
+class CRYPTOPP_NO_VTABLE DMAC_Base : public SameKeyLengthAs<T>, public MessageAuthenticationCode
+{
+public:
+ static std::string StaticAlgorithmName() {return std::string("DMAC(") + T::StaticAlgorithmName() + ")";}
+
+ CRYPTOPP_CONSTANT(DIGESTSIZE=T::BLOCKSIZE)
+
+ DMAC_Base() {}
+
+ void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params);
+ void Update(const byte *input, size_t length);
+ void TruncatedFinal(byte *mac, size_t size);
+ unsigned int DigestSize() const {return DIGESTSIZE;}
+
+private:
+ byte *GenerateSubKeys(const byte *key, size_t keylength);
+
+ size_t m_subkeylength;
+ SecByteBlock m_subkeys;
+ CBC_MAC<T> m_mac1;
+ typename T::Encryption m_f2;
+ unsigned int m_counter;
+};
+
+//! DMAC
+/*! Based on "CBC MAC for Real-Time Data Sources" by Erez Petrank
+ and Charles Rackoff. T should be a class derived from BlockCipherDocumentation.
+*/
+template <class T>
+class DMAC : public MessageAuthenticationCodeFinal<DMAC_Base<T> >
+{
+public:
+ DMAC() {}
+ DMAC(const byte *key, size_t length=DMAC_Base<T>::DEFAULT_KEYLENGTH)
+ {this->SetKey(key, length);}
+};
+
+template <class T>
+void DMAC_Base<T>::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
+{
+ m_subkeylength = T::StaticGetValidKeyLength(T::BLOCKSIZE);
+ m_subkeys.resize(2*UnsignedMin((unsigned int)T::BLOCKSIZE, m_subkeylength));
+ m_mac1.SetKey(GenerateSubKeys(key, length), m_subkeylength, params);
+ m_f2.SetKey(m_subkeys+m_subkeys.size()/2, m_subkeylength, params);
+ m_counter = 0;
+ m_subkeys.resize(0);
+}
+
+template <class T>
+void DMAC_Base<T>::Update(const byte *input, size_t length)
+{
+ m_mac1.Update(input, length);
+ m_counter = (unsigned int)((m_counter + length) % T::BLOCKSIZE);
+}
+
+template <class T>
+void DMAC_Base<T>::TruncatedFinal(byte *mac, size_t size)
+{
+ ThrowIfInvalidTruncatedSize(size);
+
+ byte pad[T::BLOCKSIZE];
+ byte padByte = byte(T::BLOCKSIZE-m_counter);
+ memset(pad, padByte, padByte);
+ m_mac1.Update(pad, padByte);
+ m_mac1.TruncatedFinal(mac, size);
+ m_f2.ProcessBlock(mac);
+
+ m_counter = 0; // reset for next message
+}
+
+template <class T>
+byte *DMAC_Base<T>::GenerateSubKeys(const byte *key, size_t keylength)
+{
+ typename T::Encryption cipher(key, keylength);
+ memset(m_subkeys, 0, m_subkeys.size());
+ cipher.ProcessBlock(m_subkeys);
+ m_subkeys[m_subkeys.size()/2 + T::BLOCKSIZE - 1] = 1;
+ cipher.ProcessBlock(m_subkeys+m_subkeys.size()/2);
+ return m_subkeys;
+}
+
+NAMESPACE_END
+
+#endif