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