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 1.5 2007/01/31 16:42:43 asterix
17 *#* Write md2_update function.
19 *#* Revision 1.4 2007/01/31 13:51:57 asterix
20 *#* Write md2_compute function.
22 *#* Revision 1.2 2007/01/30 17:31:44 asterix
23 *#* Add function prototypes.
25 *#* Revision 1.1 2007/01/30 15:53:26 batt
26 *#* Add first md2 skel.
32 #include <string.h> //memset();
33 #include <cfg/compiler.h>
36 * Official array of 256 byte pemutation contructed from digits of pi, defined
39 static uint8_t md2_perm[256] =
41 41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,
42 19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188,
43 76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,
44 138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251,
45 245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63,
46 148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50,
47 39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165,
48 181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210,
49 150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157,
50 112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27,
51 96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
52 85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197,
53 234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65,
54 129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123,
55 8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233,
56 203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228,
57 166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237,
58 31, 26, 219, 153, 141, 51, 159, 17, 131, 20
61 * Pad function. Fill input array with unsigned char until
62 * lenght of block is equal to CONFIG_MD2_BLOCK_LEN.
65 static void md2_pad(void *block, size_t len_pad)
67 if (len_pad <= CONFIG_MD2_BLOCK_LEN)
69 for(int i=(CONFIG_MD2_BLOCK_LEN-len_pad);i<len_pad; i++)
71 block[i]=(uint8_t)len_pad;
76 static void md2_compute(void *state, void *checksum, void *block)
79 uint8_t compute_array[CONFIG_MD2_BLOCK_LEN * 3];
82 * Copy state and checksum context in compute array.
84 memcpy(compute_array, state, CONFIG_MD2_BLOCK_LEN);
85 memcpy(compute_array + CONFIG_MD2_BLOCK_LEN, state, CONFIG_MD2_BLOCK_LEN);
88 * Fill compute array with state XOR block
90 for(int i=0; i< CONFIG_MD2_BLOCK_LEN; i++)
91 compute_array[i + (CONFIG_MD2_BLOCK_LEN * 2)] = state[i] ^ block[i];
96 for(i=0; i<NUM_COMPUTE_ROUNDS; i++)
98 for(int j=0; j<COMPUTE_ARRAY_LEN; j++)
100 compute_array[j] ^= md2_perm [t];
101 t = compute_array[j];
104 t = (t + i) & 0xff; //modulo 256.
109 t = checksum[CONFIG_MD2_BLOCK_LEN - 1];
111 for(i=0; i< CONFIG_MD2_BLOCK_LEN; i++)
113 checksum[i] ^= md2_perm [block[i] ^ t];
118 * Update state and clean compute array.
120 memcpy(state, compute_array, CONFIG_MD2_BLOCK_LEN);
121 memset(compute_array, 0, sizeof(compute_array));
125 * Algorithm initialization.
127 * \param empty context.
129 void md2_init(Md2Context *context)
131 context->counter = 0;
132 memset(context->state, 0, sizeof(context->state));
133 memset(context->checksum, 0, sizeof(context->checksum));
142 void md2_update(Md2Context *context, void *block_in, size_t block_len)
144 uint8_t store_block_len; //Lenght of block store in context buffer
145 uint8_t empty_block_len; //Lenght of block empty in context buffer
147 store_block_len = context->counter;
148 empty_block_len = CONFIG_MD2_BLOCK_LEN - store_block_len;
151 * Fill context buffer with input block and compute it.
153 if(block_len > empty_block_len)
155 memcpy(context->buffer[store_block_len], block_in, empty_block_len);
156 md2_compute(context->state, context->checksum, context->buffer);
157 block_len -= empty_block_len;
162 memcpy(context->buffer[store_block_len], block_in, block_len);
163 context->counter += block_len;
168 * Split input in block long CONFIG_MD2_BLOCK_LEN and compute it.
170 for(int i = empty_block_len + 1; i + CONFIG_MD2_BLOCK_LEN < block_len; i += CONFIG_MD2_BLOCK_LEN)
172 memcpy(context->buffer, block_in[i], CONFIG_MD2_BLOCK_LEN);
173 md2_compute(context->state, context->checksum, context->buffer);
177 * Copy remaining block in context buffer and update context counter.
179 memcpy(context->buffer, block_in[i], block_len - i);
180 context->counter = block_len - i;
186 void md2_end(Md2Context *context, void *msg_digest)