1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
// mdc.h - originally written and placed in the public domain by Wei Dai
/// \file mdc.h
/// \brief Classes for the MDC message digest
#ifndef CRYPTOPP_MDC_H
#define CRYPTOPP_MDC_H
#include "seckey.h"
#include "secblock.h"
#include "misc.h"
// GCC cast warning
#define HashWordPtr(x) ((HashWordType*)(void*)(x))
#define ConstHashWordPtr(x) ((const HashWordType*)(const void*)(x))
NAMESPACE_BEGIN(CryptoPP)
/// \tparam B BlockCipher derived class
/// \brief MDC_Info cipher information
template <class B>
struct MDC_Info : public FixedBlockSize<B::DIGESTSIZE>, public FixedKeyLength<B::BLOCKSIZE>
{
static std::string StaticAlgorithmName() {return std::string("MDC/")+B::StaticAlgorithmName();}
};
/// \brief MDC cipher
/// \tparam H HashTransformation derived class
/// \details MDC() is a construction by Peter Gutmann to turn an iterated hash function into a PRF
/// \sa <a href="http://www.cryptopp.com/wiki/MDC">MDC</a>
template <class H>
class MDC : public MDC_Info<H>
{
/// \brief MDC cipher encryption operation
class CRYPTOPP_NO_VTABLE Enc : public BlockCipherImpl<MDC_Info<H> >
{
typedef typename H::HashWordType HashWordType;
public:
void UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs ¶ms)
{
CRYPTOPP_UNUSED(params);
this->AssertValidKeyLength(length);
ConditionalByteReverse(BIG_ENDIAN_ORDER, Key(), ConstHashWordPtr(userKey), this->KEYLENGTH);
}
void ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
{
ConditionalByteReverse(BIG_ENDIAN_ORDER, Buffer(), ConstHashWordPtr(inBlock), this->BLOCKSIZE);
H::Transform(Buffer(), Key());
if (xorBlock)
{
ConditionalByteReverse(BIG_ENDIAN_ORDER, Buffer(), Buffer(), this->BLOCKSIZE);
xorbuf(outBlock, xorBlock, m_buffer, this->BLOCKSIZE);
}
else
{
ConditionalByteReverse(BIG_ENDIAN_ORDER, HashWordPtr(outBlock), Buffer(), this->BLOCKSIZE);
}
}
bool IsPermutation() const {return false;}
unsigned int OptimalDataAlignment() const {return sizeof(HashWordType);}
private:
HashWordType *Key() {return HashWordPtr(m_key.data());}
const HashWordType *Key() const {return ConstHashWordPtr(m_key.data());}
HashWordType *Buffer() const {return HashWordPtr(m_buffer.data());}
// VC60 workaround: bug triggered if using FixedSizeAllocatorWithCleanup
FixedSizeSecBlock<byte, MDC_Info<H>::KEYLENGTH, AllocatorWithCleanup<byte> > m_key;
mutable FixedSizeSecBlock<byte, MDC_Info<H>::BLOCKSIZE, AllocatorWithCleanup<byte> > m_buffer;
};
public:
// use BlockCipher interface
typedef BlockCipherFinal<ENCRYPTION, Enc> Encryption;
};
NAMESPACE_END
#endif
|
