summaryrefslogtreecommitdiff
path: root/modes.h
blob: a4f5bbed976ed18a56a5dd262703efe034b7fc9e (plain)
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
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
#ifndef CRYPTOPP_MODES_H
#define CRYPTOPP_MODES_H

/*! \file
*/

#include "cryptlib.h"
#include "secblock.h"
#include "misc.h"
#include "strciphr.h"
#include "argnames.h"
#include "algparam.h"

NAMESPACE_BEGIN(CryptoPP)

//! Cipher mode documentation. See NIST SP 800-38A for definitions of these modes.

/*! Each class derived from this one defines two types, Encryption and Decryption, 
	both of which implement the SymmetricCipher interface.
	For each mode there are two classes, one of which is a template class,
	and the other one has a name that ends in "_ExternalCipher".
	The "external cipher" mode objects hold a reference to the underlying block cipher,
	instead of holding an instance of it. The reference must be passed in to the constructor.
	For the "cipher holder" classes, the CIPHER template parameter should be a class
	derived from BlockCipherDocumentation, for example DES or AES.
*/
struct CipherModeDocumentation : public SymmetricCipherDocumentation
{
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CipherModeBase : public SymmetricCipher
{
public:
	size_t MinKeyLength() const {return m_cipher->MinKeyLength();}
	size_t MaxKeyLength() const {return m_cipher->MaxKeyLength();}
	size_t DefaultKeyLength() const {return m_cipher->DefaultKeyLength();}
	size_t GetValidKeyLength(size_t n) const {return m_cipher->GetValidKeyLength(n);}
	bool IsValidKeyLength(size_t n) const {return m_cipher->IsValidKeyLength(n);}

	unsigned int OptimalDataAlignment() const {return BlockSize();}

	unsigned int IVSize() const {return BlockSize();}
	void GetNextIV(byte *IV);
	virtual IV_Requirement IVRequirement() const =0;

protected:
	inline unsigned int BlockSize() const {assert(m_register.size() > 0); return (unsigned int)m_register.size();}
	virtual void SetFeedbackSize(unsigned int feedbackSize)
	{
		if (!(feedbackSize == 0 || feedbackSize == BlockSize()))
			throw InvalidArgument("CipherModeBase: feedback size cannot be specified for this cipher mode");
	}
	virtual void ResizeBuffers()
	{
		m_register.New(m_cipher->BlockSize());
	}

	BlockCipher *m_cipher;
	SecByteBlock m_register;
};

template <class POLICY_INTERFACE>
class CRYPTOPP_NO_VTABLE ModePolicyCommonTemplate : public CipherModeBase, public POLICY_INTERFACE
{
	unsigned int GetAlignment() const {return m_cipher->BlockAlignment();}
	void CipherSetKey(const NameValuePairs &params, const byte *key, size_t length);
	void CipherGetNextIV(byte *IV) {CipherModeBase::GetNextIV(IV);}
};

template <class POLICY_INTERFACE>
void ModePolicyCommonTemplate<POLICY_INTERFACE>::CipherSetKey(const NameValuePairs &params, const byte *key, size_t length)
{
	m_cipher->SetKey(key, length, params);
	ResizeBuffers();
	int feedbackSize = params.GetIntValueWithDefault(Name::FeedbackSize(), 0);
	SetFeedbackSize(feedbackSize);
}

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CFB_ModePolicy : public ModePolicyCommonTemplate<CFB_CipherAbstractPolicy>
{
public:
	IV_Requirement IVRequirement() const {return RANDOM_IV;}
	static const char * CRYPTOPP_API StaticAlgorithmName() {return "CFB";}

protected:
	unsigned int GetBytesPerIteration() const {return m_feedbackSize;}
	byte * GetRegisterBegin() {return m_register + BlockSize() - m_feedbackSize;}
	void TransformRegister()
	{
		assert(m_cipher->IsForwardTransformation());	// CFB mode needs the "encrypt" direction of the underlying block cipher, even to decrypt
		m_cipher->ProcessBlock(m_register, m_temp);
		unsigned int updateSize = BlockSize()-m_feedbackSize;
		memmove_s(m_register, m_register.size(), m_register+m_feedbackSize, updateSize);
		memcpy_s(m_register+updateSize, m_register.size()-updateSize, m_temp, m_feedbackSize);
	}
	void CipherResynchronize(const byte *iv)
	{
		memcpy_s(m_register, m_register.size(), iv, BlockSize());
		TransformRegister();
	}
	void SetFeedbackSize(unsigned int feedbackSize)
	{
		if (feedbackSize > BlockSize())
			throw InvalidArgument("CFB_Mode: invalid feedback size");
		m_feedbackSize = feedbackSize ? feedbackSize : BlockSize();
	}
	void ResizeBuffers()
	{
		CipherModeBase::ResizeBuffers();
		m_temp.New(BlockSize());
	}

	SecByteBlock m_temp;
	unsigned int m_feedbackSize;
};

inline void CopyOrZero(void *dest, const void *src, size_t s)
{
	if (src)
		memcpy_s(dest, s, src, s);
	else
		memset(dest, 0, s);
}

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE OFB_ModePolicy : public ModePolicyCommonTemplate<AdditiveCipherAbstractPolicy>
{
public:
	bool IsRandomAccess() const {return false;}
	IV_Requirement IVRequirement() const {return UNIQUE_IV;}
	static const char * CRYPTOPP_API StaticAlgorithmName() {return "OFB";}

private:
	unsigned int GetBytesPerIteration() const {return BlockSize();}
	unsigned int GetIterationsToBuffer() const {return 1;}
	void WriteKeystream(byte *keystreamBuffer, size_t iterationCount)
	{
		assert(iterationCount == 1);
		assert(m_cipher->IsForwardTransformation());	// OFB mode needs the "encrypt" direction of the underlying block cipher, even to decrypt
		m_cipher->ProcessBlock(keystreamBuffer);
		memcpy_s(m_register, m_register.size(), keystreamBuffer, BlockSize());
	}
	void CipherResynchronize(byte *keystreamBuffer, const byte *iv)
	{
		CopyOrZero(keystreamBuffer, iv, BlockSize());
	}
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CTR_ModePolicy : public ModePolicyCommonTemplate<AdditiveCipherAbstractPolicy>
{
public:
	bool IsRandomAccess() const {return true;}
	IV_Requirement IVRequirement() const {return UNIQUE_IV;}
	void CipherGetNextIV(byte *IV);
	static const char * CRYPTOPP_API StaticAlgorithmName() {return "CTR";}

private:
	unsigned int GetBytesPerIteration() const {return BlockSize();}
	unsigned int GetIterationsToBuffer() const {return m_cipher->OptimalNumberOfParallelBlocks();}
	void WriteKeystream(byte *buffer, size_t iterationCount)
		{OperateKeystream(WRITE_KEYSTREAM, buffer, NULL, iterationCount);}
	bool CanOperateKeystream() const {return true;}
	void OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount);
	void CipherResynchronize(byte *keystreamBuffer, const byte *iv);
	void SeekToIteration(lword iterationCount);

	inline void ProcessMultipleBlocks(byte *output, const byte *input, size_t n);

	SecByteBlock m_counterArray;
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE BlockOrientedCipherModeBase : public CipherModeBase
{
public:
	void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params);
	unsigned int MandatoryBlockSize() const {return BlockSize();}
	bool IsRandomAccess() const {return false;}
	bool IsSelfInverting() const {return false;}
	bool IsForwardTransformation() const {return m_cipher->IsForwardTransformation();}
	void Resynchronize(const byte *iv) {memcpy_s(m_register, m_register.size(), iv, BlockSize());}
	void ProcessData(byte *outString, const byte *inString, size_t length);

protected:
	bool RequireAlignedInput() const {return true;}
	virtual void ProcessBlocks(byte *outString, const byte *inString, size_t numberOfBlocks) =0;
	void ResizeBuffers()
	{
		CipherModeBase::ResizeBuffers();
		m_buffer.New(BlockSize());
	}

	SecByteBlock m_buffer;
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE ECB_OneWay : public BlockOrientedCipherModeBase
{
public:
	void SetKey(const byte *key, size_t length, const NameValuePairs &params = g_nullNameValuePairs)
		{m_cipher->SetKey(key, length, params); BlockOrientedCipherModeBase::ResizeBuffers();}
	IV_Requirement IVRequirement() const {return NOT_RESYNCHRONIZABLE;}
	unsigned int OptimalBlockSize() const {return BlockSize() * m_cipher->OptimalNumberOfParallelBlocks();}
	void ProcessBlocks(byte *outString, const byte *inString, size_t numberOfBlocks)
		{m_cipher->ProcessAndXorMultipleBlocks(inString, NULL, outString, numberOfBlocks);}
	static const char * CRYPTOPP_API StaticAlgorithmName() {return "ECB";}
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CBC_ModeBase : public BlockOrientedCipherModeBase
{
public:
	IV_Requirement IVRequirement() const {return UNPREDICTABLE_RANDOM_IV;}
	bool RequireAlignedInput() const {return false;}
	unsigned int MinLastBlockSize() const {return 0;}
	static const char * CRYPTOPP_API StaticAlgorithmName() {return "CBC";}
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CBC_Encryption : public CBC_ModeBase
{
public:
	void ProcessBlocks(byte *outString, const byte *inString, size_t numberOfBlocks);
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CBC_CTS_Encryption : public CBC_Encryption
{
public:
	void SetStolenIV(byte *iv) {m_stolenIV = iv;}
	unsigned int MinLastBlockSize() const {return BlockSize()+1;}
	void ProcessLastBlock(byte *outString, const byte *inString, size_t length);
	static const char * CRYPTOPP_API StaticAlgorithmName() {return "CBC/CTS";}

protected:
	void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
	{
		CBC_Encryption::UncheckedSetKey(key, length, params);
		m_stolenIV = params.GetValueWithDefault(Name::StolenIV(), (byte *)NULL);
	}

	byte *m_stolenIV;
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CBC_Decryption : public CBC_ModeBase
{
public:
	void ProcessBlocks(byte *outString, const byte *inString, size_t numberOfBlocks);
	
protected:
	void ResizeBuffers()
	{
		BlockOrientedCipherModeBase::ResizeBuffers();
		m_temp.New(BlockSize());
	}
	SecByteBlock m_temp;
};

class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE CBC_CTS_Decryption : public CBC_Decryption
{
public:
	unsigned int MinLastBlockSize() const {return BlockSize()+1;}
	void ProcessLastBlock(byte *outString, const byte *inString, size_t length);
};

//! _
template <class CIPHER, class BASE>
class CipherModeFinalTemplate_CipherHolder : protected ObjectHolder<CIPHER>, public AlgorithmImpl<BASE, CipherModeFinalTemplate_CipherHolder<CIPHER, BASE> >
{
public:
	CipherModeFinalTemplate_CipherHolder()
	{
		this->m_cipher = &this->m_object;
		this->ResizeBuffers();
	}
	CipherModeFinalTemplate_CipherHolder(const byte *key, size_t length)
	{
		this->m_cipher = &this->m_object;
		this->SetKey(key, length);
	}
	CipherModeFinalTemplate_CipherHolder(const byte *key, size_t length, const byte *iv)
	{
		this->m_cipher = &this->m_object;
		this->SetKey(key, length, MakeParameters(Name::IV(), iv));
	}
	CipherModeFinalTemplate_CipherHolder(const byte *key, size_t length, const byte *iv, int feedbackSize)
	{
		this->m_cipher = &this->m_object;
		this->SetKey(key, length, MakeParameters(Name::IV(), iv)(Name::FeedbackSize(), feedbackSize));
	}

	static std::string CRYPTOPP_API StaticAlgorithmName()
		{return CIPHER::StaticAlgorithmName() + "/" + BASE::StaticAlgorithmName();}
};

//! _
template <class BASE>
class CipherModeFinalTemplate_ExternalCipher : public BASE
{
public:
	CipherModeFinalTemplate_ExternalCipher() {}
	CipherModeFinalTemplate_ExternalCipher(BlockCipher &cipher)
		{SetCipher(cipher);}
	CipherModeFinalTemplate_ExternalCipher(BlockCipher &cipher, const byte *iv, int feedbackSize = 0)
		{SetCipherWithIV(cipher, iv, feedbackSize);}

	void SetCipher(BlockCipher &cipher);
	void SetCipherWithIV(BlockCipher &cipher, const byte *iv, int feedbackSize = 0);
};

template <class BASE>
void CipherModeFinalTemplate_ExternalCipher<BASE>::SetCipher(BlockCipher &cipher)
{
	this->ThrowIfResynchronizable();
	this->m_cipher = &cipher;
	this->ResizeBuffers();
}

template <class BASE>
void CipherModeFinalTemplate_ExternalCipher<BASE>::SetCipherWithIV(BlockCipher &cipher, const byte *iv, int feedbackSize)
{
	this->ThrowIfInvalidIV(iv);
	this->m_cipher = &cipher;
	this->ResizeBuffers();
	this->SetFeedbackSize(feedbackSize);
	if (this->IsResynchronizable())
		this->Resynchronize(iv);
}

CRYPTOPP_DLL_TEMPLATE_CLASS CFB_CipherTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> >;
CRYPTOPP_DLL_TEMPLATE_CLASS CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> >;
CRYPTOPP_DLL_TEMPLATE_CLASS CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> >;

//! CFB mode
template <class CIPHER>
struct CFB_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > Encryption;
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > Decryption;
};

//! CFB mode, external cipher
struct CFB_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > Encryption;
	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > Decryption;
};

//! CFB mode FIPS variant, requiring full block plaintext according to FIPS 800-38A
template <class CIPHER>
struct CFB_FIPS_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, CFB_RequireFullDataBlocks<CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > > Encryption;
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, CFB_RequireFullDataBlocks<CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > > Decryption;
};

//! CFB mode FIPS variant, requiring full block plaintext according to FIPS 800-38A, external cipher
struct CFB_FIPS_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, CFB_RequireFullDataBlocks<CFB_EncryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > > Encryption;
	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, CFB_RequireFullDataBlocks<CFB_DecryptionTemplate<AbstractPolicyHolder<CFB_CipherAbstractPolicy, CFB_ModePolicy> > > > > Decryption;
};

CRYPTOPP_DLL_TEMPLATE_CLASS AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, OFB_ModePolicy> >;

//! OFB mode
template <class CIPHER>
struct OFB_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, OFB_ModePolicy> > > > Encryption;
	typedef Encryption Decryption;
};

//! OFB mode, external cipher
struct OFB_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, OFB_ModePolicy> > > > Encryption;
	typedef Encryption Decryption;
};

CRYPTOPP_DLL_TEMPLATE_CLASS AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, CTR_ModePolicy> >;

//! CTR mode
template <class CIPHER>
struct CTR_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ConcretePolicyHolder<Empty, AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, CTR_ModePolicy> > > > Encryption;
	typedef Encryption Decryption;
};

//! CTR mode, external cipher
struct CTR_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<ConcretePolicyHolder<Empty, AdditiveCipherTemplate<AbstractPolicyHolder<AdditiveCipherAbstractPolicy, CTR_ModePolicy> > > > Encryption;
	typedef Encryption Decryption;
};

//! ECB mode
template <class CIPHER>
struct ECB_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, ECB_OneWay> Encryption;
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Decryption, ECB_OneWay> Decryption;
};

CRYPTOPP_DLL_TEMPLATE_CLASS CipherModeFinalTemplate_ExternalCipher<ECB_OneWay>;

//! ECB mode, external cipher
struct ECB_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<ECB_OneWay> Encryption;
	typedef Encryption Decryption;
};

//! CBC mode
template <class CIPHER>
struct CBC_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, CBC_Encryption> Encryption;
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Decryption, CBC_Decryption> Decryption;
};

CRYPTOPP_DLL_TEMPLATE_CLASS CipherModeFinalTemplate_ExternalCipher<CBC_Encryption>;
CRYPTOPP_DLL_TEMPLATE_CLASS CipherModeFinalTemplate_ExternalCipher<CBC_Decryption>;

//! CBC mode, external cipher
struct CBC_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<CBC_Encryption> Encryption;
	typedef CipherModeFinalTemplate_ExternalCipher<CBC_Decryption> Decryption;
};

//! CBC mode with ciphertext stealing
template <class CIPHER>
struct CBC_CTS_Mode : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Encryption, CBC_CTS_Encryption> Encryption;
	typedef CipherModeFinalTemplate_CipherHolder<CPP_TYPENAME CIPHER::Decryption, CBC_CTS_Decryption> Decryption;
};

CRYPTOPP_DLL_TEMPLATE_CLASS CipherModeFinalTemplate_ExternalCipher<CBC_CTS_Encryption>;
CRYPTOPP_DLL_TEMPLATE_CLASS CipherModeFinalTemplate_ExternalCipher<CBC_CTS_Decryption>;

//! CBC mode with ciphertext stealing, external cipher
struct CBC_CTS_Mode_ExternalCipher : public CipherModeDocumentation
{
	typedef CipherModeFinalTemplate_ExternalCipher<CBC_CTS_Encryption> Encryption;
	typedef CipherModeFinalTemplate_ExternalCipher<CBC_CTS_Decryption> Decryption;
};

#ifdef CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY
typedef CFB_Mode_ExternalCipher::Encryption CFBEncryption;
typedef CFB_Mode_ExternalCipher::Decryption CFBDecryption;
typedef OFB_Mode_ExternalCipher::Encryption OFB;
typedef CTR_Mode_ExternalCipher::Encryption CounterMode;
#endif

NAMESPACE_END

#endif