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#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,
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	S33=	11,
27 
	S34=	15,
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};
29 
 
30 
typedef struct MD4Table MD4Table;
31 
struct MD4Table
32 
{
33 
	uchar	x;	/* index into data block */
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	uchar	rot;	/* amount to rotate left by */
35 
};
36 
 
37 
static MD4Table tab[] =
38 
{
39 
	/* round 1 */
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/*[0]*/	{ 0,	S11},
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	{ 1,	S12},
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	{ 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},
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	{ 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*, u32int*, ulong);
95 
static void decode(u32int*, uchar*, ulong);
96 
 
97 
static void
98 
md4block(uchar *p, ulong len, MD4state *s)
99 
{
100 
	int i;
101 
	u32int a, b, c, d, tmp;
102 
	MD4Table *t;
103 
	uchar *end;
104 
	u32int 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 
	u32int 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 (u32int) into output (uchar). Assumes len is
242 
 *	a multiple of 4.
243 
 */
244 
static void
245 
encode(uchar *output, u32int *input, ulong len)
246 
{
247 
	u32int 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 (u32int). Assumes len is
261 
 *	a multiple of 4.
262 
 */
263 
static void
264 
decode(u32int *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 
}