Crypto++ 7.0 Free C++ class library of cryptographic schemes

modes.cpp
1 // modes.cpp - originally written and placed in the public domain by Wei Dai
2
3 #include "pch.h"
4
5 #ifndef CRYPTOPP_IMPORTS
6
7 #include "modes.h"
8 #include "misc.h"
9
10 #if defined(CRYPTOPP_DEBUG)
11 #include "des.h"
12 #endif
13
14 NAMESPACE_BEGIN(CryptoPP)
15
16 #if defined(CRYPTOPP_DEBUG) && !defined(CRYPTOPP_DOXYGEN_PROCESSING)
17 void Modes_TestInstantiations()
18 {
19 CFB_Mode<DES>::Encryption m0;
20 CFB_Mode<DES>::Decryption m1;
21 OFB_Mode<DES>::Encryption m2;
22 CTR_Mode<DES>::Encryption m3;
23 ECB_Mode<DES>::Encryption m4;
24 CBC_Mode<DES>::Encryption m5;
25 }
26 #endif
27
28 void CipherModeBase::ResizeBuffers()
29 {
30 m_register.New(m_cipher->BlockSize());
31 }
32
33 void CFB_ModePolicy::Iterate(byte *output, const byte *input, CipherDir dir, size_t iterationCount)
34 {
35 CRYPTOPP_ASSERT(input); CRYPTOPP_ASSERT(output);
36 CRYPTOPP_ASSERT(m_cipher->IsForwardTransformation());
37 CRYPTOPP_ASSERT(m_register.size() == BlockSize());
38 CRYPTOPP_ASSERT(m_temp.size() == BlockSize());
39 CRYPTOPP_ASSERT(iterationCount > 0);
40
41 const unsigned int s = BlockSize();
42 if (dir == ENCRYPTION)
43 {
44 m_cipher->ProcessAndXorBlock(m_register, input, output);
45 if (iterationCount > 1)
46 m_cipher->AdvancedProcessBlocks(output, PtrAdd(input,s), PtrAdd(output,s), (iterationCount-1)*s, 0);
47 memcpy(m_register, PtrAdd(output,(iterationCount-1)*s), s);
48 }
49 else
50 {
51 // make copy first in case of in-place decryption
52 memcpy(m_temp, PtrAdd(input,(iterationCount-1)*s), s);
53 if (iterationCount > 1)
54 m_cipher->AdvancedProcessBlocks(input, PtrAdd(input,s), PtrAdd(output,s), (iterationCount-1)*s, BlockTransformation::BT_ReverseDirection);
55 m_cipher->ProcessAndXorBlock(m_register, input, output);
56 memcpy(m_register, m_temp, s);
57 }
58 }
59
60 void CFB_ModePolicy::TransformRegister()
61 {
62 CRYPTOPP_ASSERT(m_cipher->IsForwardTransformation());
63 CRYPTOPP_ASSERT(m_register.size() == BlockSize());
64 CRYPTOPP_ASSERT(m_temp.size() == BlockSize());
65
66 const ptrdiff_t updateSize = BlockSize()-m_feedbackSize;
67 m_cipher->ProcessBlock(m_register, m_temp);
68 memmove_s(m_register, m_register.size(), PtrAdd(m_register.begin(),m_feedbackSize), updateSize);
69 memcpy_s(PtrAdd(m_register.begin(),updateSize), m_register.size()-updateSize, m_temp, m_feedbackSize);
70 }
71
72 void CFB_ModePolicy::CipherResynchronize(const byte *iv, size_t length)
73 {
74 CRYPTOPP_ASSERT(length == BlockSize());
75 CRYPTOPP_ASSERT(m_register.size() == BlockSize());
76
77 CopyOrZero(m_register, m_register.size(), iv, length);
78 TransformRegister();
79 }
80
81 void CFB_ModePolicy::SetFeedbackSize(unsigned int feedbackSize)
82 {
83 if (feedbackSize > BlockSize())
84 throw InvalidArgument("CFB_Mode: invalid feedback size");
85 m_feedbackSize = feedbackSize ? feedbackSize : BlockSize();
86 }
87
88 void CFB_ModePolicy::ResizeBuffers()
89 {
90 CipherModeBase::ResizeBuffers();
91 m_temp.New(BlockSize());
92 }
93
94 byte* CFB_ModePolicy::GetRegisterBegin()
95 {
96 CRYPTOPP_ASSERT(!m_register.empty());
97 CRYPTOPP_ASSERT(BlockSize() >= m_feedbackSize);
98 return PtrAdd(m_register.begin(), BlockSize() - m_feedbackSize);
99 }
100
101 void OFB_ModePolicy::WriteKeystream(byte *keystreamBuffer, size_t iterationCount)
102 {
103 CRYPTOPP_ASSERT(m_cipher->IsForwardTransformation());
104 CRYPTOPP_ASSERT(m_register.size() == BlockSize());
105 CRYPTOPP_ASSERT(iterationCount > 0);
106
107 const unsigned int s = BlockSize();
108 m_cipher->ProcessBlock(m_register, keystreamBuffer);
109 if (iterationCount > 1)
110 m_cipher->AdvancedProcessBlocks(keystreamBuffer, NULLPTR, PtrAdd(keystreamBuffer, s), s*(iterationCount-1), 0);
111 memcpy(m_register, PtrAdd(keystreamBuffer, (iterationCount-1)*s), s);
112 }
113
114 void OFB_ModePolicy::CipherResynchronize(byte *keystreamBuffer, const byte *iv, size_t length)
115 {
116 CRYPTOPP_UNUSED(keystreamBuffer), CRYPTOPP_UNUSED(length);
117 CRYPTOPP_ASSERT(m_register.size() == BlockSize());
118 CRYPTOPP_ASSERT(length == BlockSize());
119
120 CopyOrZero(m_register, m_register.size(), iv, length);
121 }
122
123 void CTR_ModePolicy::SeekToIteration(lword iterationCount)
124 {
125 int carry=0;
126 for (int i=BlockSize()-1; i>=0; i--)
127 {
128 unsigned int sum = m_register[i] + (byte)iterationCount + carry;
129 m_counterArray[i] = byte(sum & 0xff);
130 carry = sum >> 8;
131 iterationCount >>= 8;
132 }
133 }
134
135 void CTR_ModePolicy::IncrementCounterBy256()
136 {
137 IncrementCounterByOne(m_counterArray, BlockSize()-1);
138 }
139
140 void CTR_ModePolicy::OperateKeystream(KeystreamOperation /*operation*/, byte *output, const byte *input, size_t iterationCount)
141 {
142 CRYPTOPP_ASSERT(m_cipher->IsForwardTransformation());
143 CRYPTOPP_ASSERT(m_counterArray.size() == BlockSize());
144
145 const unsigned int s = BlockSize();
146 const unsigned int inputIncrement = input ? s : 0;
147
148 while (iterationCount)
149 {
150 const byte lsb = m_counterArray[s-1];
151 const size_t blocks = UnsignedMin(iterationCount, 256U-lsb);
152
153 m_cipher->AdvancedProcessBlocks(m_counterArray, input, output, blocks*s, BlockTransformation::BT_InBlockIsCounter|BlockTransformation::BT_AllowParallel);
154 if ((m_counterArray[s-1] = byte(lsb + blocks)) == 0)
155 IncrementCounterBy256();
156
157 output = PtrAdd(output, blocks*s);
158 input = PtrAdd(input, blocks*inputIncrement);
159 iterationCount -= blocks;
160 }
161 }
162
163 void CTR_ModePolicy::CipherResynchronize(byte *keystreamBuffer, const byte *iv, size_t length)
164 {
165 CRYPTOPP_UNUSED(keystreamBuffer), CRYPTOPP_UNUSED(length);
166 CRYPTOPP_ASSERT(m_register.size() == BlockSize());
167 CRYPTOPP_ASSERT(length == BlockSize());
168
169 CopyOrZero(m_register, m_register.size(), iv, length);
170 m_counterArray.Assign(m_register.begin(), m_register.size());
171 }
172
173 void BlockOrientedCipherModeBase::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
174 {
175 m_cipher->SetKey(key, length, params);
176 ResizeBuffers();
177 if (IsResynchronizable())
178 {
179 size_t ivLength;
180 const byte *iv = GetIVAndThrowIfInvalid(params, ivLength);
181 Resynchronize(iv, (int)ivLength);
182 }
183 }
184
185 void BlockOrientedCipherModeBase::ResizeBuffers()
186 {
187 CipherModeBase::ResizeBuffers();
188 m_buffer.New(BlockSize());
189 }
190
191 void ECB_OneWay::ProcessData(byte *outString, const byte *inString, size_t length)
192 {
193 CRYPTOPP_ASSERT(length%BlockSize()==0);
194 m_cipher->AdvancedProcessBlocks(inString, NULLPTR, outString, length, BlockTransformation::BT_AllowParallel);
195 }
196
197 void CBC_Encryption::ProcessData(byte *outString, const byte *inString, size_t length)
198 {
199 CRYPTOPP_ASSERT(length%BlockSize()==0);
200 CRYPTOPP_ASSERT(m_register.size() == BlockSize());
201 if (!length) return;
202
203 const unsigned int blockSize = BlockSize();
204 m_cipher->AdvancedProcessBlocks(inString, m_register, outString, blockSize, BlockTransformation::BT_XorInput);
205 if (length > blockSize)
206 m_cipher->AdvancedProcessBlocks(PtrAdd(inString,blockSize), outString, PtrAdd(outString,blockSize), length-blockSize, BlockTransformation::BT_XorInput);
207 memcpy(m_register, PtrAdd(outString, length - blockSize), blockSize);
208 }
209
210 size_t CBC_CTS_Encryption::ProcessLastBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength)
211 {
212 CRYPTOPP_UNUSED(outLength);
213 const size_t used = inLength;
214 const unsigned int blockSize = BlockSize();
215
216 if (inLength <= BlockSize())
217 {
218 if (!m_stolenIV)
219 throw InvalidArgument("CBC_Encryption: message is too short for ciphertext stealing");
220
221 // steal from IV
222 memcpy(outString, m_register, inLength);
223 outString = m_stolenIV;
224 }
225 else
226 {
227 // steal from next to last block
228 xorbuf(m_register, inString, blockSize);
229 m_cipher->ProcessBlock(m_register);
230 inString = PtrAdd(inString, blockSize);
231 inLength -= blockSize;
232 memcpy(PtrAdd(outString, blockSize), m_register, inLength);
233 }
234
235 // output last full ciphertext block
236 xorbuf(m_register, inString, inLength);
237 m_cipher->ProcessBlock(m_register);
238 memcpy(outString, m_register, blockSize);
239
240 return used;
241 }
242
243 void CBC_Decryption::ResizeBuffers()
244 {
245 BlockOrientedCipherModeBase::ResizeBuffers();
246 m_temp.New(BlockSize());
247 }
248
249 void CBC_Decryption::ProcessData(byte *outString, const byte *inString, size_t length)
250 {
251 CRYPTOPP_ASSERT(length%BlockSize()==0);
252 if (!length) {return;}
253
254 // save copy now in case of in-place decryption
255 const unsigned int blockSize = BlockSize();
256 memcpy(m_temp, PtrAdd(inString,length-blockSize), blockSize);
257 if (length > blockSize)
258 m_cipher->AdvancedProcessBlocks(PtrAdd(inString,blockSize), inString, PtrAdd(outString,blockSize), length-blockSize, BlockTransformation::BT_ReverseDirection|BlockTransformation::BT_AllowParallel);
259 m_cipher->ProcessAndXorBlock(inString, m_register, outString);
260 m_register.swap(m_temp);
261 }
262
263 size_t CBC_CTS_Decryption::ProcessLastBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength)
264 {
265 CRYPTOPP_UNUSED(outLength);
266 const byte *pn1, *pn2;
267 const size_t used = inLength;
268 const bool stealIV = inLength <= BlockSize();
269 const unsigned int blockSize = BlockSize();
270
271 if (stealIV)
272 {
273 pn1 = inString;
274 pn2 = m_register;
275 }
276 else
277 {
278 pn1 = PtrAdd(inString, blockSize);
279 pn2 = inString;
280 inLength -= blockSize;
281 }
282
283 // decrypt last partial plaintext block
284 memcpy(m_temp, pn2, blockSize);
285 m_cipher->ProcessBlock(m_temp);
286 xorbuf(m_temp, pn1, inLength);
287
288 if (stealIV)
289 {
290 memcpy(outString, m_temp, inLength);
291 }
292 else
293 {
294 memcpy(PtrAdd(outString, blockSize), m_temp, inLength);
295 // decrypt next to last plaintext block
296 memcpy(m_temp, pn1, inLength);
297 m_cipher->ProcessBlock(m_temp);
298 xorbuf(outString, m_temp, m_register, blockSize);
299 }
300
301 return used;
302 }
303
304 NAMESPACE_END
305
306 #endif
BlockTransformation::BT_AllowParallel
Allow parallel transformations.
Definition: cryptlib.h:897
InvalidArgument
An invalid argument was detected.
Definition: cryptlib.h:202
CBC_Decryption::ProcessData
void ProcessData(byte *outString, const byte *inString, size_t length)
Encrypt or decrypt an array of bytes.
Definition: modes.cpp:249
memmove_s
void memmove_s(void *dest, size_t sizeInBytes, const void *src, size_t count)
Bounds checking replacement for memmove()
Definition: misc.h:484
BlockOrientedCipherModeBase::Resynchronize
void Resynchronize(const byte *iv, int length=-1)
Resynchronize with an IV.
Definition: modes.h:259
misc.h
Utility functions for the Crypto++ library.
IncrementCounterByOne
void IncrementCounterByOne(byte *inout, unsigned int size)
Performs an addition with carry on a block of bytes.
Definition: misc.h:1167
modes.h
Classes for block cipher modes of operation.
CipherDir
CipherDir
Specifies a direction for a cipher to operate.
Definition: cryptlib.h:123
memcpy_s
void memcpy_s(void *dest, size_t sizeInBytes, const void *src, size_t count)
Bounds checking replacement for memcpy()
Definition: misc.h:439
SecBlock::New
void New(size_type newSize)
Change size without preserving contents.
Definition: secblock.h:959
CopyOrZero
void CopyOrZero(void *dest, size_t dsize, const void *src, size_t ssize)
Initialize a block of memory.
Definition: modes.h:196
CBC_CTS_Encryption::ProcessLastBlock
size_t ProcessLastBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength)
Encrypt or decrypt the last block of data.
Definition: modes.cpp:210
ENCRYPTION
the cipher is performing encryption
Definition: cryptlib.h:125
BlockTransformation::BlockSize
virtual unsigned int BlockSize() const =0
Provides the block size of the cipher.
CipherModeFinalTemplate_CipherHolder
Block cipher mode of operation aggregate.
Definition: modes.h:344
CBC_CTS_Decryption::ProcessLastBlock
size_t ProcessLastBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength)
Encrypt or decrypt the last block of data.
Definition: modes.cpp:263
SecBlock::Assign
void Assign(const T *ptr, size_type len)
Set contents and size from an array.
Definition: secblock.h:835
pch.h
Precompiled header file.
UnsignedMin
const T1 UnsignedMin(const T1 &a, const T2 &b)
Safe comparison of values that could be neagtive and incorrectly promoted.
Definition: misc.h:602
CRYPTOPP_ASSERT
#define CRYPTOPP_ASSERT(exp)
Debugging and diagnostic assertion.
Definition: trap.h:60
Name::BlockSize
const char * BlockSize()
int, in bytes
Definition: argnames.h:27
des.h
Classes for DES, 2-key Triple-DES, 3-key Triple-DES and DESX.
PtrAdd
PTR PtrAdd(PTR pointer, OFF offset)
Create a pointer with an offset.
Definition: misc.h:371
xorbuf
void xorbuf(byte *buf, const byte *mask, size_t count)
Performs an XOR of a buffer with a mask.
Definition: misc.cpp:32
BlockTransformation::BT_XorInput
Xor inputs before transformation.
Definition: cryptlib.h:893
BlockOrientedCipherModeBase::UncheckedSetKey
void UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &params)
Sets the key for this object without performing parameter validation.
Definition: modes.cpp:173
KeystreamOperation
KeystreamOperation
Keystream operation flags.
Definition: strciphr.h:88
BlockTransformation::BT_ReverseDirection
perform the transformation in reverse
Definition: cryptlib.h:895
CryptoPP
Crypto++ library namespace.
SimpleKeyingInterface::IsResynchronizable
bool IsResynchronizable() const
Determines if the object can be resynchronized.
Definition: cryptlib.h:712
CBC_Encryption::ProcessData
void ProcessData(byte *outString, const byte *inString, size_t length)
Encrypt or decrypt an array of bytes.
Definition: modes.cpp:197
ECB_OneWay::ProcessData
void ProcessData(byte *outString, const byte *inString, size_t length)
Encrypt or decrypt an array of bytes.
Definition: modes.cpp:191
SecBlock::size
size_type size() const
Provides the count of elements in the SecBlock.
Definition: secblock.h:791
BlockTransformation::BT_InBlockIsCounter
inBlock is a counter
Definition: cryptlib.h:889
NameValuePairs
Interface for retrieving values given their names.
Definition: cryptlib.h:293