halfmd4.c
1.98 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/cryptohash.h>
/* F, G and H are basic MD4 functions: selection, majority, parity */
#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
#define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
/*
* The generic round function. The application is so specific that
* we don't bother protecting all the arguments with parens, as is generally
* good macro practice, in favor of extra legibility.
* Rotation is separate from addition to prevent recomputation
*/
#define ROUND(f, a, b, c, d, x, s) \
(a += f(b, c, d) + x, a = (a << s) | (a >> (32 - s)))
#define K1 0
#define K2 013240474631UL
#define K3 015666365641UL
/*
* Basic cut-down MD4 transform. Returns only 32 bits of result.
*/
__u32 half_md4_transform(__u32 buf[4], __u32 const in[8])
{
__u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
/* Round 1 */
ROUND(F, a, b, c, d, in[0] + K1, 3);
ROUND(F, d, a, b, c, in[1] + K1, 7);
ROUND(F, c, d, a, b, in[2] + K1, 11);
ROUND(F, b, c, d, a, in[3] + K1, 19);
ROUND(F, a, b, c, d, in[4] + K1, 3);
ROUND(F, d, a, b, c, in[5] + K1, 7);
ROUND(F, c, d, a, b, in[6] + K1, 11);
ROUND(F, b, c, d, a, in[7] + K1, 19);
/* Round 2 */
ROUND(G, a, b, c, d, in[1] + K2, 3);
ROUND(G, d, a, b, c, in[3] + K2, 5);
ROUND(G, c, d, a, b, in[5] + K2, 9);
ROUND(G, b, c, d, a, in[7] + K2, 13);
ROUND(G, a, b, c, d, in[0] + K2, 3);
ROUND(G, d, a, b, c, in[2] + K2, 5);
ROUND(G, c, d, a, b, in[4] + K2, 9);
ROUND(G, b, c, d, a, in[6] + K2, 13);
/* Round 3 */
ROUND(H, a, b, c, d, in[3] + K3, 3);
ROUND(H, d, a, b, c, in[7] + K3, 9);
ROUND(H, c, d, a, b, in[2] + K3, 11);
ROUND(H, b, c, d, a, in[6] + K3, 15);
ROUND(H, a, b, c, d, in[1] + K3, 3);
ROUND(H, d, a, b, c, in[5] + K3, 9);
ROUND(H, c, d, a, b, in[0] + K3, 11);
ROUND(H, b, c, d, a, in[4] + K3, 15);
buf[0] += a;
buf[1] += b;
buf[2] += c;
buf[3] += d;
return buf[1]; /* "most hashed" word */
}
EXPORT_SYMBOL(half_md4_transform);