4 * Copyright 2007 Develer S.r.l. (http://www.develer.com/)
5 * This file is part of DevLib - See README.devlib for information.
8 * \brief MD2 Message-Digest algorithm.
11 * \author Daniele Basile <asterix@develer.com>
16 *#* Revision 1.9 2007/02/02 13:10:01 asterix
17 *#* Fix some bugs in md2_pad and md2_update fuction.
19 *#* Revision 1.8 2007/02/01 14:45:56 asterix
20 *#* Rewrite md2_update function and fix some bug.
22 *#* Revision 1.7 2007/01/31 18:04:15 asterix
23 *#* Write md2_end function
25 *#* Revision 1.4 2007/01/31 13:51:57 asterix
26 *#* Write md2_compute function.
28 *#* Revision 1.2 2007/01/30 17:31:44 asterix
29 *#* Add function prototypes.
31 *#* Revision 1.1 2007/01/30 15:53:26 batt
32 *#* Add first md2 skel.
38 #include <string.h> //memset(), memcpy();
39 #include <cfg/compiler.h>
40 #include <cfg/debug.h> //ASSERT()
41 #include <cfg/macros.h> //MIN()
45 * Official array of 256 byte pemutation contructed from digits of pi, defined
48 static uint8_t md2_perm[256] = {
49 41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,
50 19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188,
51 76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,
52 138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251,
53 245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63,
54 148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50,
55 39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165,
56 181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210,
57 150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157,
58 112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27,
59 96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
60 85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197,
61 234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65,
62 129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123,
63 8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233,
64 203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228,
65 166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237,
66 31, 26, 219, 153, 141, 51, 159, 17, 131, 20
70 * Pad function. Put len_pad unsigned char in
73 static void md2_pad(void *_block, size_t len_pad)
77 block = (uint8_t *)_block;
79 ASSERT(len_pad <= CONFIG_MD2_BLOCK_LEN);
82 * Fill input block with len_pad char.
84 memset(block, len_pad, len_pad);
88 static void md2_compute(void *_state, void *_checksum, void *_block)
92 uint8_t compute_array[COMPUTE_ARRAY_LEN];
97 state = (uint8_t *)_state;
98 checksum = (uint8_t *)_checksum;
99 block = (uint8_t *)_block;
102 * Copy state and checksum context in compute array.
104 memcpy(compute_array, state, CONFIG_MD2_BLOCK_LEN);
105 memcpy(compute_array + CONFIG_MD2_BLOCK_LEN, block, CONFIG_MD2_BLOCK_LEN);
108 * Fill compute array with state XOR block
110 for(i = 0; i < CONFIG_MD2_BLOCK_LEN; i++)
111 compute_array[i + (CONFIG_MD2_BLOCK_LEN * 2)] = state[i] ^ block[i];
116 for(i = 0; i < NUM_COMPUTE_ROUNDS; i++)
118 for(int j = 0; j < COMPUTE_ARRAY_LEN; j++)
120 compute_array[j] ^= md2_perm [t];
121 t = compute_array[j];
124 t = (t + i) & 0xff; //modulo 256.
129 t = checksum[CONFIG_MD2_BLOCK_LEN - 1];
131 for(i = 0; i < CONFIG_MD2_BLOCK_LEN; i++)
133 checksum[i] ^= md2_perm [block[i] ^ t];
138 * Update state and clean compute array.
140 memcpy(state, compute_array, CONFIG_MD2_BLOCK_LEN);
141 memset(compute_array, 0, sizeof(compute_array));
145 * Algorithm initialization.
147 * \param empty context.
149 void md2_init(Md2Context *context)
152 memset(context, 0, sizeof(Md2Context));
159 void md2_update(Md2Context *context, void *_block_in, size_t block_len)
165 * Choose a number of block that fill input context buffer.
167 size_t missing_len = MIN(block_len, CONFIG_MD2_BLOCK_LEN - context->counter);
169 block_in = (uint8_t *)_block_in;
174 * Copy in the buffer input block.
176 memcpy(&context->buffer[context->counter], block_in, missing_len);
179 * Update a context counter, input block length and remaning
180 * context buffer block lenght.
182 context->counter += missing_len;
183 block_len -= missing_len;
184 block_in += missing_len;
187 * If buffer is full, compute it.
189 if (context->counter >= CONFIG_MD2_BLOCK_LEN)
191 md2_compute(context->state, context->checksum, context->buffer);
192 context->counter = 0;
199 * Ends MD2 message digest operation, writing the message digest and cleaning context.
201 void md2_end(Md2Context *context, void *msg_digest)
203 uint8_t buf[CONFIG_MD2_BLOCK_LEN];
206 * Pad remaning context buffer.
208 md2_pad(buf, CONFIG_MD2_BLOCK_LEN - context->counter);
211 * Update context and checksum.
213 md2_update(context, buf, CONFIG_MD2_BLOCK_LEN - context->counter);
215 memcpy(buf, context->checksum, CONFIG_MD2_BLOCK_LEN);
217 md2_update(context, buf, CONFIG_MD2_BLOCK_LEN);
220 * Copy first CONFIG_MD2_BLOCK_LEN byte of context's state
221 * in msg_digest. The msg_digest is the message digest of
224 memcpy(msg_digest, context->state, CONFIG_MD2_BLOCK_LEN);
229 memset(context, 0, sizeof(context));