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
NAMESPACE_BEGIN(CryptoPP)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
ResizeBuffers()28 void CipherModeBase::ResizeBuffers()
29 {
30 m_register.New(m_cipher->BlockSize());
31 }
32
Iterate(byte * output,const byte * input,CipherDir dir,size_t iterationCount)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
TransformRegister()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
CipherResynchronize(const byte * iv,size_t length)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
SetFeedbackSize(unsigned int feedbackSize)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
ResizeBuffers()88 void CFB_ModePolicy::ResizeBuffers()
89 {
90 CipherModeBase::ResizeBuffers();
91 m_temp.New(BlockSize());
92 }
93
GetRegisterBegin()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
WriteKeystream(byte * keystreamBuffer,size_t iterationCount)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
CipherResynchronize(byte * keystreamBuffer,const byte * iv,size_t length)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
SeekToIteration(lword iterationCount)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
IncrementCounterBy256()135 void CTR_ModePolicy::IncrementCounterBy256()
136 {
137 IncrementCounterByOne(m_counterArray, BlockSize()-1);
138 }
139
OperateKeystream(KeystreamOperation,byte * output,const byte * input,size_t iterationCount)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
CipherResynchronize(byte * keystreamBuffer,const byte * iv,size_t length)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
UncheckedSetKey(const byte * key,unsigned int length,const NameValuePairs & params)173 void BlockOrientedCipherModeBase::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs ¶ms)
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
ResizeBuffers()185 void BlockOrientedCipherModeBase::ResizeBuffers()
186 {
187 CipherModeBase::ResizeBuffers();
188 m_buffer.New(BlockSize());
189 }
190
ProcessData(byte * outString,const byte * inString,size_t length)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
ProcessData(byte * outString,const byte * inString,size_t length)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
ProcessLastBlock(byte * outString,size_t outLength,const byte * inString,size_t inLength)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
ResizeBuffers()243 void CBC_Decryption::ResizeBuffers()
244 {
245 BlockOrientedCipherModeBase::ResizeBuffers();
246 m_temp.New(BlockSize());
247 }
248
ProcessData(byte * outString,const byte * inString,size_t length)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
ProcessLastBlock(byte * outString,size_t outLength,const byte * inString,size_t inLength)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
307