md4.c - vx32 - Local 9vx git repository for patches.
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---
md4.c (4260B)
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1 #include "os.h"
2 #include "libsec.h"
3
4 /*
5 * This MD4 is implemented from the description in Stinson's Cryptography,
6 * theory and practice. -- presotto
7 */
8
9 /*
10 * Rotate ammounts used in the algorithm
11 */
12 enum
13 {
14 S11= 3,
15 S12= 7,
16 S13= 11,
17 S14= 19,
18
19 S21= 3,
20 S22= 5,
21 S23= 9,
22 S24= 13,
23
24 S31= 3,
25 S32= 9,
26 S33= 11,
27 S34= 15,
28 };
29
30 typedef struct MD4Table MD4Table;
31 struct MD4Table
32 {
33 uchar x; /* index into data block */
34 uchar rot; /* amount to rotate left by */
35 };
36
37 static MD4Table tab[] =
38 {
39 /* round 1 */
40 /*[0]*/ { 0, S11},
41 { 1, S12},
42 { 2, S13},
43 { 3, S14},
44 { 4, S11},
45 { 5, S12},
46 { 6, S13},
47 { 7, S14},
48 { 8, S11},
49 { 9, S12},
50 { 10, S13},
51 { 11, S14},
52 { 12, S11},
53 { 13, S12},
54 { 14, S13},
55 { 15, S14},
56
57 /* round 2 */
58 /*[16]*/{ 0, S21},
59 { 4, S22},
60 { 8, S23},
61 { 12, S24},
62 { 1, S21},
63 { 5, S22},
64 { 9, S23},
65 { 13, S24},
66 { 2, S21},
67 { 6, S22},
68 { 10, S23},
69 { 14, S24},
70 { 3, S21},
71 { 7, S22},
72 { 11, S23},
73 { 15, S24},
74
75 /* round 3 */
76 /*[32]*/{ 0, S31},
77 { 8, S32},
78 { 4, S33},
79 { 12, S34},
80 { 2, S31},
81 { 10, S32},
82 { 6, S33},
83 { 14, S34},
84 { 1, S31},
85 { 9, S32},
86 { 5, S33},
87 { 13, S34},
88 { 3, S31},
89 { 11, S32},
90 { 7, S33},
91 { 15, S34},
92 };
93
94 static void encode(uchar*, uint32*, ulong);
95 static void decode(uint32*, uchar*, ulong);
96
97 static void
98 md4block(uchar *p, ulong len, MD4state *s)
99 {
100 int i;
101 uint32 a, b, c, d, tmp;
102 MD4Table *t;
103 uchar *end;
104 uint32 x[16];
105
106 for(end = p+len; p < end; p += 64){
107 a = s->state[0];
108 b = s->state[1];
109 c = s->state[2];
110 d = s->state[3];
111
112 decode(x, p, 64);
113
114 for(i = 0; i < 48; i++){
115 t = tab + i;
116 switch(i>>4){
117 case 0:
118 a += (b & c) | (~b & d);
119 break;
120 case 1:
121 a += ((b & c) | (b & d) | (c & d)) + 0x5A827999;
122 break;
123 case 2:
124 a += (b ^ c ^ d) + 0x6ED9EBA1;
125 break;
126 }
127 a += x[t->x];
128 a = (a << t->rot) | (a >> (32 - t->rot));
129
130 /* rotate variables */
131 tmp = d;
132 d = c;
133 c = b;
134 b = a;
135 a = tmp;
136 }
137
138 s->state[0] += a;
139 s->state[1] += b;
140 s->state[2] += c;
141 s->state[3] += d;
142
143 s->len += 64;
144 }
145 }
146
147 MD4state*
148 md4(uchar *p, ulong len, uchar *digest, MD4state *s)
149 {
150 uint32 x[16];
151 uchar buf[128];
152 int i;
153 uchar *e;
154
155 if(s == nil){
156 s = malloc(sizeof(*s));
157 if(s == nil)
158 return nil;
159 memset(s, 0, sizeof(*s));
160 s->malloced = 1;
161 }
162
163 if(s->seeded == 0){
164 /* seed the state, these constants would look nicer big-endian */
165 s->state[0] = 0x67452301;
166 s->state[1] = 0xefcdab89;
167 s->state[2] = 0x98badcfe;
168 s->state[3] = 0x10325476;
169 s->seeded = 1;
170 }
171
172 /* fill out the partial 64 byte block from previous calls */
173 if(s->blen){
174 i = 64 - s->blen;
175 if(len < i)
176 i = len;
177 memmove(s->buf + s->blen, p, i);
178 len -= i;
179 s->blen += i;
180 p += i;
181 if(s->blen == 64){
182 md4block(s->buf, s->blen, s);
183 s->blen = 0;
184 }
185 }
186
187 /* do 64 byte blocks */
188 i = len & ~0x3f;
189 if(i){
190 md4block(p, i, s);
191 len -= i;
192 p += i;
193 }
194
195 /* save the left overs if not last call */
196 if(digest == 0){
197 if(len){
198 memmove(s->buf, p, len);
199 s->blen += len;
200 }
201 return s;
202 }
203
204 /*
205 * this is the last time through, pad what's left with 0x80,
206 * 0's, and the input count to create a multiple of 64 bytes
207 */
208 if(s->blen){
209 p = s->buf;
210 len = s->blen;
211 } else {
212 memmove(buf, p, len);
213 p = buf;
214 }
215 s->len += len;
216 e = p + len;
217 if(len < 56)
218 i = 56 - len;
219 else
220 i = 120 - len;
221 memset(e, 0, i);
222 *e = 0x80;
223 len += i;
224
225 /* append the count */
226 x[0] = s->len<<3;
227 x[1] = s->len>>29;
228 encode(p+len, x, 8);
229
230 /* digest the last part */
231 md4block(p, len+8, s);
232
233 /* return result and free state */
234 encode(digest, s->state, MD4dlen);
235 if(s->malloced == 1)
236 free(s);
237 return nil;
238 }
239
240 /*
241 * encodes input (uint32) into output (uchar). Assumes len is
242 * a multiple of 4.
243 */
244 static void
245 encode(uchar *output, uint32 *input, ulong len)
246 {
247 uint32 x;
248 uchar *e;
249
250 for(e = output + len; output < e;) {
251 x = *input++;
252 *output++ = x;
253 *output++ = x >> 8;
254 *output++ = x >> 16;
255 *output++ = x >> 24;
256 }
257 }
258
259 /*
260 * decodes input (uchar) into output (uint32). Assumes len is
261 * a multiple of 4.
262 */
263 static void
264 decode(uint32 *output, uchar *input, ulong len)
265 {
266 uchar *e;
267
268 for(e = input+len; input < e; input += 4)
269 *output++ = input[0] | (input[1] << 8) |
270 (input[2] << 16) | (input[3] << 24);
271 }