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#ifndef CRYPTOPP_DMAC_H
00002
#define CRYPTOPP_DMAC_H
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00004
#include "cbcmac.h"
00005
00006 NAMESPACE_BEGIN(CryptoPP)
00007
00008 template <class T>
00009 class DMAC_Base : public
SameKeyLengthAs<T>, public
MessageAuthenticationCode
00010 {
00011
public:
00012
static std::string StaticAlgorithmName() {
return std::string(
"DMAC(") + T::StaticAlgorithmName() +
")";}
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00014
enum {DIGESTSIZE=T::BLOCKSIZE};
00015
00016 DMAC_Base() {}
00017
00018
void CheckedSetKey(
void *, Empty empty,
const byte *key,
unsigned int length,
const NameValuePairs ¶ms);
00019
void Update(
const byte *input,
unsigned int length);
00020
void TruncatedFinal(byte *mac,
unsigned int size);
00021
unsigned int DigestSize()
const {
return DIGESTSIZE;}
00022
00023
private:
00024 byte *GenerateSubKeys(
const byte *key,
unsigned int keylength);
00025
00026
unsigned int m_subkeylength;
00027
SecByteBlock m_subkeys;
00028
CBC_MAC<T> m_mac1;
00029
typename T::Encryption m_f2;
00030
unsigned int m_counter;
00031 };
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00033
00034
00035
00036
00037
template <
class T>
00038 class DMAC :
public MessageAuthenticationCodeTemplate<DMAC_Base<T> >
00039 {
00040
public:
00041
DMAC() {}
00042
DMAC(
const byte *key,
unsigned int length=DMAC_Base<T>::DEFAULT_KEYLENGTH)
00043 {SetKey(key, length);}
00044 };
00045
00046
template <
class T>
00047
void DMAC_Base<T>::CheckedSetKey(
void *, Empty empty,
const byte *key,
unsigned int length,
const NameValuePairs ¶ms)
00048 {
00049 m_subkeylength = T::StaticGetValidKeyLength(T::BLOCKSIZE);
00050 m_subkeys.resize(2*STDMAX((
unsigned int)T::BLOCKSIZE, m_subkeylength));
00051 m_mac1.SetKey(GenerateSubKeys(key, length), m_subkeylength, params);
00052 m_f2.SetKey(m_subkeys+m_subkeys.size()/2, m_subkeylength, params);
00053 m_counter = 0;
00054 m_subkeys.resize(0);
00055 }
00056
00057
template <
class T>
00058
void DMAC_Base<T>::Update(
const byte *input,
unsigned int length)
00059 {
00060 m_mac1.Update(input, length);
00061 m_counter = (m_counter + length) % T::BLOCKSIZE;
00062 }
00063
00064
template <
class T>
00065
void DMAC_Base<T>::TruncatedFinal(byte *mac,
unsigned int size)
00066 {
00067 ThrowIfInvalidTruncatedSize(size);
00068
00069 byte pad[T::BLOCKSIZE];
00070 byte padByte = byte(T::BLOCKSIZE-m_counter);
00071 memset(pad, padByte, padByte);
00072 m_mac1.Update(pad, padByte);
00073 m_mac1.TruncatedFinal(mac, size);
00074 m_f2.ProcessBlock(mac);
00075 }
00076
00077
template <
class T>
00078 byte *DMAC_Base<T>::GenerateSubKeys(
const byte *key,
unsigned int keylength)
00079 {
00080
typename T::Encryption cipher(key, keylength);
00081 memset(m_subkeys, 0, m_subkeys.size());
00082 cipher.ProcessBlock(m_subkeys);
00083 m_subkeys[m_subkeys.size()/2 + T::BLOCKSIZE - 1] = 1;
00084 cipher.ProcessBlock(m_subkeys+m_subkeys.size()/2);
00085
return m_subkeys;
00086 }
00087
00088 NAMESPACE_END
00089
00090
#endif