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[proxmark3-svn] / client / loclass / cipherutils.c
1 /*****************************************************************************
2 * WARNING
3 *
4 * THIS CODE IS CREATED FOR EXPERIMENTATION AND EDUCATIONAL USE ONLY.
5 *
6 * USAGE OF THIS CODE IN OTHER WAYS MAY INFRINGE UPON THE INTELLECTUAL
7 * PROPERTY OF OTHER PARTIES, SUCH AS INSIDE SECURE AND HID GLOBAL,
8 * AND MAY EXPOSE YOU TO AN INFRINGEMENT ACTION FROM THOSE PARTIES.
9 *
10 * THIS CODE SHOULD NEVER BE USED TO INFRINGE PATENTS OR INTELLECTUAL PROPERTY RIGHTS.
11 *
12 *****************************************************************************
13 *
14 * This file is part of loclass. It is a reconstructon of the cipher engine
15 * used in iClass, and RFID techology.
16 *
17 * The implementation is based on the work performed by
18 * Flavio D. Garcia, Gerhard de Koning Gans, Roel Verdult and
19 * Milosch Meriac in the paper "Dismantling IClass".
20 *
21 * Copyright (C) 2014 Martin Holst Swende
22 *
23 * This is free software: you can redistribute it and/or modify
24 * it under the terms of the GNU General Public License version 2 as published
25 * by the Free Software Foundation.
26 *
27 * This file is distributed in the hope that it will be useful,
28 * but WITHOUT ANY WARRANTY; without even the implied warranty of
29 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
30 * GNU General Public License for more details.
31 *
32 * You should have received a copy of the GNU General Public License
33 * along with loclass. If not, see <http://www.gnu.org/licenses/>.
34 *
35 *
36 *
37 ****************************************************************************/
38
39 #include <stdint.h>
40 #include <stdio.h>
41 #include <string.h>
42 #include "fileutils.h"
43 #include "cipherutils.h"
44 /**
45 *
46 * @brief Return and remove the first bit (x0) in the stream : <x0 x1 x2 x3 ... xn >
47 * @param stream
48 * @return
49 */
50 bool headBit( BitstreamIn *stream)
51 {
52 int bytepos = stream->position >> 3; // divide by 8
53 int bitpos = (stream->position++) & 7; // mask out 00000111
54 return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1;
55 }
56 /**
57 * @brief Return and remove the last bit (xn) in the stream: <x0 x1 x2 ... xn>
58 * @param stream
59 * @return
60 */
61 bool tailBit( BitstreamIn *stream)
62 {
63 int bitpos = stream->numbits -1 - (stream->position++);
64
65 int bytepos= bitpos >> 3;
66 bitpos &= 7;
67 return (*(stream->buffer + bytepos) >> (7-bitpos)) & 1;
68 }
69 /**
70 * @brief Pushes bit onto the stream
71 * @param stream
72 * @param bit
73 */
74 void pushBit( BitstreamOut* stream, bool bit)
75 {
76 int bytepos = stream->position >> 3; // divide by 8
77 int bitpos = stream->position & 7;
78 *(stream->buffer+bytepos) |= (bit & 1) << (7 - bitpos);
79 stream->position++;
80 stream->numbits++;
81 }
82
83 /**
84 * @brief Pushes the lower six bits onto the stream
85 * as b0 b1 b2 b3 b4 b5 b6
86 * @param stream
87 * @param bits
88 */
89 void push6bits( BitstreamOut* stream, uint8_t bits)
90 {
91 pushBit(stream, bits & 0x20);
92 pushBit(stream, bits & 0x10);
93 pushBit(stream, bits & 0x08);
94 pushBit(stream, bits & 0x04);
95 pushBit(stream, bits & 0x02);
96 pushBit(stream, bits & 0x01);
97 }
98
99 /**
100 * @brief bitsLeft
101 * @param stream
102 * @return number of bits left in stream
103 */
104 int bitsLeft( BitstreamIn *stream)
105 {
106 return stream->numbits - stream->position;
107 }
108 /**
109 * @brief numBits
110 * @param stream
111 * @return Number of bits stored in stream
112 */
113 int numBits(BitstreamOut *stream)
114 {
115 return stream->numbits;
116 }
117
118 void x_num_to_bytes(uint64_t n, size_t len, uint8_t* dest)
119 {
120 while (len--) {
121 dest[len] = (uint8_t) n;
122 n >>= 8;
123 }
124 }
125
126 uint64_t x_bytes_to_num(uint8_t* src, size_t len)
127 {
128 uint64_t num = 0;
129 while (len--)
130 {
131 num = (num << 8) | (*src);
132 src++;
133 }
134 return num;
135 }
136 uint8_t reversebytes(uint8_t b) {
137 b = (b & 0xF0) >> 4 | (b & 0x0F) << 4;
138 b = (b & 0xCC) >> 2 | (b & 0x33) << 2;
139 b = (b & 0xAA) >> 1 | (b & 0x55) << 1;
140 return b;
141 }
142 void reverse_arraybytes(uint8_t* arr, size_t len)
143 {
144 uint8_t i;
145 for( i =0; i< len ; i++)
146 {
147 arr[i] = reversebytes(arr[i]);
148 }
149 }
150 void reverse_arraycopy(uint8_t* arr, uint8_t* dest, size_t len)
151 {
152 uint8_t i;
153 for( i =0; i< len ; i++)
154 {
155 dest[i] = reversebytes(arr[i]);
156 }
157 }
158
159 void printarr(char * name, uint8_t* arr, int len)
160 {
161 int cx;
162 size_t outsize = 40+strlen(name)+len*5;
163 char* output = malloc(outsize);
164 memset(output, 0,outsize);
165
166 int i ;
167 cx = snprintf(output,outsize, "uint8_t %s[] = {", name);
168 for(i =0 ; i< len ; i++)
169 {
170 cx += snprintf(output+cx,outsize-cx,"0x%02x,",*(arr+i));//5 bytes per byte
171 }
172 cx += snprintf(output+cx,outsize-cx,"};");
173 prnlog(output);
174 }
175
176 void printvar(char * name, uint8_t* arr, int len)
177 {
178 int cx;
179 size_t outsize = 40+strlen(name)+len*2;
180 char* output = malloc(outsize);
181 memset(output, 0,outsize);
182
183 int i ;
184 cx = snprintf(output,outsize,"%s = ", name);
185 for(i =0 ; i< len ; i++)
186 {
187 cx += snprintf(output+cx,outsize-cx,"%02x",*(arr+i));//2 bytes per byte
188 }
189
190 prnlog(output);
191 }
192
193 void printarr_human_readable(char * title, uint8_t* arr, int len)
194 {
195 int cx;
196 size_t outsize = 100+strlen(title)+len*4;
197 char* output = malloc(outsize);
198 memset(output, 0,outsize);
199
200
201 int i;
202 cx = snprintf(output,outsize, "\n\t%s\n", title);
203 for(i =0 ; i< len ; i++)
204 {
205 if(i % 16 == 0)
206 cx += snprintf(output+cx,outsize-cx,"\n%02x| ", i );
207 cx += snprintf(output+cx,outsize-cx, "%02x ",*(arr+i));
208 }
209 prnlog(output);
210 free(output);
211 }
212
213 //-----------------------------
214 // Code for testing below
215 //-----------------------------
216
217
218 int testBitStream()
219 {
220 uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF};
221 uint8_t output [] = {0,0,0,0,0,0,0,0};
222 BitstreamIn in = { input, sizeof(input) * 8,0};
223 BitstreamOut out ={ output, 0,0}
224 ;
225 while(bitsLeft(&in) > 0)
226 {
227 pushBit(&out, headBit(&in));
228 //printf("Bits left: %d\n", bitsLeft(&in));
229 //printf("Bits out: %d\n", numBits(&out));
230 }
231 if(memcmp(input, output, sizeof(input)) == 0)
232 {
233 prnlog(" Bitstream test 1 ok");
234 }else
235 {
236 prnlog(" Bitstream test 1 failed");
237 uint8_t i;
238 for(i = 0 ; i < sizeof(input) ; i++)
239 {
240 prnlog(" IN %02x, OUT %02x", input[i], output[i]);
241 }
242 return 1;
243 }
244 return 0;
245 }
246
247 int testReversedBitstream()
248 {
249 uint8_t input [] = {0xDE,0xAD,0xBE,0xEF,0xDE,0xAD,0xBE,0xEF};
250 uint8_t reverse [] = {0,0,0,0,0,0,0,0};
251 uint8_t output [] = {0,0,0,0,0,0,0,0};
252 BitstreamIn in = { input, sizeof(input) * 8,0};
253 BitstreamOut out ={ output, 0,0};
254 BitstreamIn reversed_in ={ reverse, sizeof(input)*8,0};
255 BitstreamOut reversed_out ={ reverse,0 ,0};
256
257 while(bitsLeft(&in) > 0)
258 {
259 pushBit(&reversed_out, tailBit(&in));
260 }
261 while(bitsLeft(&reversed_in) > 0)
262 {
263 pushBit(&out, tailBit(&reversed_in));
264 }
265 if(memcmp(input, output, sizeof(input)) == 0)
266 {
267 prnlog(" Bitstream test 2 ok");
268 }else
269 {
270 prnlog(" Bitstream test 2 failed");
271 uint8_t i;
272 for(i = 0 ; i < sizeof(input) ; i++)
273 {
274 prnlog(" IN %02x, MIDDLE: %02x, OUT %02x", input[i],reverse[i], output[i]);
275 }
276 return 1;
277 }
278 return 0;
279 }
280
281
282 int testCipherUtils(void)
283 {
284 prnlog("[+] Testing some internals...");
285 int retval = 0;
286 retval |= testBitStream();
287 retval |= testReversedBitstream();
288 return retval;
289 }
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