Security Scol plugin
dmac.h
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1// dmac.h - originally written and placed in the public domain by Wei Dai
2
5
6#ifndef CRYPTOPP_DMAC_H
7#define CRYPTOPP_DMAC_H
8
9#include "cbcmac.h"
10
11NAMESPACE_BEGIN(CryptoPP)
12
13
16template <class T>
17class CRYPTOPP_NO_VTABLE DMAC_Base : public SameKeyLengthAs<T>, public MessageAuthenticationCode
18{
19public:
20 CRYPTOPP_CONSTANT(DIGESTSIZE=T::BLOCKSIZE);
21 static std::string StaticAlgorithmName() {return std::string("DMAC(") + T::StaticAlgorithmName() + ")";}
22
23 virtual~DMAC_Base() {}
24 DMAC_Base() : m_subkeylength(0), m_counter(0) {}
25
26 void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params);
27 void Update(const byte *input, size_t length);
28 void TruncatedFinal(byte *mac, size_t size);
29 unsigned int DigestSize() const {return DIGESTSIZE;}
30
31 std::string AlgorithmProvider() const;
32
33private:
34 byte *GenerateSubKeys(const byte *key, size_t keylength);
35
36 size_t m_subkeylength;
37 SecByteBlock m_subkeys;
38 CBC_MAC<T> m_mac1;
39 typename T::Encryption m_f2;
40 unsigned int m_counter;
41};
42
43template <class T>
45{
46 return m_f2.AlgorithmProvider();
47}
48
54template <class T>
55class DMAC : public MessageAuthenticationCodeFinal<DMAC_Base<T> >
56{
57public:
59 DMAC() {}
60
64 DMAC(const byte *key, size_t length=DMAC_Base<T>::DEFAULT_KEYLENGTH)
65 {this->SetKey(key, length);}
66};
67
68template <class T>
69void DMAC_Base<T>::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
70{
71 m_subkeylength = T::StaticGetValidKeyLength(T::BLOCKSIZE);
72 m_subkeys.resize(2*UnsignedMin((unsigned int)T::BLOCKSIZE, m_subkeylength));
73 m_mac1.SetKey(GenerateSubKeys(key, length), m_subkeylength, params);
74 m_f2.SetKey(m_subkeys+m_subkeys.size()/2, m_subkeylength, params);
75 m_counter = 0;
76 m_subkeys.resize(0);
77}
78
79template <class T>
80void DMAC_Base<T>::Update(const byte *input, size_t length)
81{
82 m_mac1.Update(input, length);
83 m_counter = (unsigned int)((m_counter + length) % T::BLOCKSIZE);
84}
85
86template <class T>
87void DMAC_Base<T>::TruncatedFinal(byte *mac, size_t size)
88{
89 ThrowIfInvalidTruncatedSize(size);
90
91 byte pad[T::BLOCKSIZE];
92 byte padByte = byte(T::BLOCKSIZE-m_counter);
93 memset(pad, padByte, padByte);
94 m_mac1.Update(pad, padByte);
95 m_mac1.TruncatedFinal(mac, size);
96 m_f2.ProcessBlock(mac);
97
98 m_counter = 0; // reset for next message
99}
100
101template <class T>
102byte *DMAC_Base<T>::GenerateSubKeys(const byte *key, size_t keylength)
103{
104 typename T::Encryption cipher(key, keylength);
105 memset(m_subkeys, 0, m_subkeys.size());
106 cipher.ProcessBlock(m_subkeys);
107 m_subkeys[m_subkeys.size()/2 + T::BLOCKSIZE - 1] = 1;
108 cipher.ProcessBlock(m_subkeys+m_subkeys.size()/2);
109 return m_subkeys;
110}
111
112NAMESPACE_END
113
114#endif
Classes for CBC MAC.
virtual std::string AlgorithmProvider() const
Retrieve the provider of this algorithm.
Definition cryptlib.h:636
CBC-MAC.
Definition cbcmac.h:44
DMAC message authentication code base class.
Definition dmac.h:18
void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
Sets the key for this object without performing parameter validation.
Definition dmac.h:69
std::string AlgorithmProvider() const
Retrieve the provider of this algorithm.
Definition dmac.h:44
void Update(const byte *input, size_t length)
Updates a hash with additional input.
Definition dmac.h:80
void TruncatedFinal(byte *mac, size_t size)
Computes the hash of the current message.
Definition dmac.h:87
unsigned int DigestSize() const
Definition dmac.h:29
DMAC message authentication code.
Definition dmac.h:56
DMAC()
Construct a DMAC.
Definition dmac.h:59
DMAC(const byte *key, size_t length=DMAC_Base< T >::DEFAULT_KEYLENGTH)
Construct a DMAC.
Definition dmac.h:64
virtual void TruncatedFinal(byte *digest, size_t digestSize)=0
Computes the hash of the current message.
virtual void Update(const byte *input, size_t length)=0
Updates a hash with additional input.
Provides class member functions to key a message authentication code.
Definition seckey.h:371
Interface for message authentication codes.
Definition cryptlib.h:1299
Interface for retrieving values given their names.
Definition cryptlib.h:322
Provides key lengths based on another class's key length.
Definition seckey.h:218
virtual void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)=0
Sets the key for this object without performing parameter validation.
unsigned char byte
8-bit unsigned datatype
Definition config_int.h:56
const T1 UnsignedMin(const T1 &a, const T2 &b)
Safe comparison of values that could be negative and incorrectly promoted.
Definition misc.h:694