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21 * library without restriction. Specifically, if other files instantiate
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26 * invalidate any other reasons why the executable file might be covered by
27 * the GNU General Public License.
29 * Copyright 2007 Develer S.r.l. (http://www.develer.com/)
33 * \brief MD2 Message-Digest algorithm.
35 * The MD2 algorithm work with a constant array of 256 permutationt
36 * defined in RFC1319. If you don't want to use a standard array of
37 * permutatione you can use a md2_perm() function that generate an
38 * array of 256 "casual" permutation. To swich from a standard array
39 * to md2_perm function you must chanche CONFIG_MD2_STD_PERM defined in
41 * If you need to store array in program memory you must define
42 * a macro _PROGMEM (for more info see cpu/pgm.h).
45 * \author Daniele Basile <asterix@develer.com>
50 #include <string.h> //memset(), memcpy();
51 #include <cfg/compiler.h>
52 #include <cfg/debug.h> //ASSERT()
53 #include <cfg/macros.h> //MIN(), countof(), ROTR();
57 #if CONFIG_MD2_STD_PERM
59 * Official array of 256 byte pemutation contructed from digits of pi, defined
62 static const uint8_t PROGMEM md2_perm[256] =
64 41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,
65 19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188,
66 76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,
67 138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251,
68 245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63,
69 148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50,
70 39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165,
71 181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210,
72 150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157,
73 112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27,
74 96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
75 85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197,
76 234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65,
77 129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123,
78 8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233,
79 203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228,
80 166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237,
81 31, 26, 219, 153, 141, 51, 159, 17, 131, 20
84 #define MD2_PERM(x) pgm_read8(&md2_perm[x])
87 * Md2_perm() function generate an array of 256 "casual" permutation.
91 * Costant define for computing an array of 256 "casual" permutation.
100 static uint8_t md2_perm(uint8_t i)
111 #define MD2_PERM(x) md2_perm(x)
117 * Pad function. Put len_pad unsigned char in
120 static void md2_pad(void *_block, size_t len_pad)
124 block = (uint8_t *)_block;
126 ASSERT(len_pad <= CONFIG_MD2_BLOCK_LEN);
129 * Fill input block with len_pad char.
131 memset(block, len_pad, len_pad);
135 static void md2_compute(void *_state, void *_checksum, void *_block)
139 uint8_t compute_array[COMPUTE_ARRAY_LEN];
144 state = (uint8_t *)_state;
145 checksum = (uint8_t *)_checksum;
146 block = (uint8_t *)_block;
149 * Copy state and checksum context in compute array.
151 memcpy(compute_array, state, CONFIG_MD2_BLOCK_LEN);
152 memcpy(compute_array + CONFIG_MD2_BLOCK_LEN, block, CONFIG_MD2_BLOCK_LEN);
155 * Fill compute array with state XOR block
157 for(i = 0; i < CONFIG_MD2_BLOCK_LEN; i++)
158 compute_array[i + (CONFIG_MD2_BLOCK_LEN * 2)] = state[i] ^ block[i];
163 for(i = 0; i < NUM_COMPUTE_ROUNDS; i++)
165 for(int j = 0; j < COMPUTE_ARRAY_LEN; j++)
167 compute_array[j] ^= MD2_PERM(t);
168 t = compute_array[j];
171 t = (t + i) & 0xff; //modulo 256.
176 t = checksum[CONFIG_MD2_BLOCK_LEN - 1];
178 for(i = 0; i < CONFIG_MD2_BLOCK_LEN; i++)
180 checksum[i] ^= MD2_PERM(block[i] ^ t);
185 * Update state and clean compute array.
187 memcpy(state, compute_array, CONFIG_MD2_BLOCK_LEN);
188 memset(compute_array, 0, sizeof(compute_array));
192 * Algorithm initialization.
194 * \param context empty context.
196 void md2_init(Md2Context *context)
199 memset(context, 0, sizeof(Md2Context));
206 void md2_update(Md2Context *context, const void *_block_in, size_t block_len)
209 const uint8_t *block_in;
213 block_in = (const uint8_t *)_block_in;
218 * Choose a number of block that fill input context buffer.
220 cpy_len = MIN(block_len, CONFIG_MD2_BLOCK_LEN - context->counter);
224 * Copy in the buffer input block.
226 memcpy(&context->buffer[context->counter], block_in, cpy_len);
229 * Update a context counter, input block length and remaning
230 * context buffer block lenght.
232 context->counter += cpy_len;
233 block_len -= cpy_len;
237 * If buffer is full, compute it.
239 if (context->counter >= CONFIG_MD2_BLOCK_LEN)
241 md2_compute(context->state, context->checksum, context->buffer);
242 context->counter = 0;
249 * Ends an MD2 message digest operation.
250 * This fuction take an context and return a pointer
253 * \param context in input.
254 * \return a pointer to context state (message digest).
256 uint8_t *md2_end(Md2Context *context)
259 uint8_t buf[CONFIG_MD2_BLOCK_LEN];
262 * Fill remaning empty context buffer.
264 md2_pad(buf, CONFIG_MD2_BLOCK_LEN - context->counter);
267 * Update context buffer and compute it.
269 md2_update(context, buf, CONFIG_MD2_BLOCK_LEN - context->counter);
272 * Add context checksum to message input.
274 md2_update(context, context->checksum, CONFIG_MD2_BLOCK_LEN);
277 return context->state; //return a pointer to message digest.
281 * This function test MD2 algorithm with a standard string specified
284 * \note This test work with official array of 256 byte pemutation
285 * contructed from digits of pi, defined in the RFC 1319.
297 "abcdefghijklmnopqrstuvwxyz",
298 "12345678901234567890123456789012345678901234567890123456789012345678901234567890"
302 const char *result[] = {
303 "\x83\x50\xe5\xa3\xe2\x4c\x15\x3d\xf2\x27\x5c\x9f\x80\x69\x27\x73",
304 "\xab\x4f\x49\x6b\xfb\x2a\x53\x0b\x21\x9f\xf3\x30\x31\xfe\x06\xb0",
305 "\x4e\x8d\xdf\xf3\x65\x02\x92\xab\x5a\x41\x08\xc3\xaa\x47\x94\x0b",
306 "\xd5\x97\x6f\x79\xd8\x3d\x3a\x0d\xc9\x80\x6c\x3c\x66\xf3\xef\xd8",
310 for (size_t i = 0; i < countof(test); i++)
313 md2_update(&context, test[i], strlen(test[i]));
315 if(memcmp(result[i], md2_end(&context), MD2_DIGEST_LEN))
325 int main(int argc, char * argv[])
329 printf("MD2 algorithm work well!\n");
331 printf("MD2 algorithm doesn't work well.\n");