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Rasmus Villemoes32483402015-02-12 15:02:40 -08001#include <linux/compiler.h>
Paul Gortmaker8bc3bcc2011-11-16 21:29:17 -05002#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07003#include <linux/cryptohash.h>
Alexander Kuleshov1c78bc12015-11-06 16:31:11 -08004#include <linux/bitops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07005
6/* F, G and H are basic MD4 functions: selection, majority, parity */
7#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
8#define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
9#define H(x, y, z) ((x) ^ (y) ^ (z))
10
11/*
12 * The generic round function. The application is so specific that
13 * we don't bother protecting all the arguments with parens, as is generally
14 * good macro practice, in favor of extra legibility.
15 * Rotation is separate from addition to prevent recomputation
16 */
17#define ROUND(f, a, b, c, d, x, s) \
Alexander Kuleshov1c78bc12015-11-06 16:31:11 -080018 (a += f(b, c, d) + x, a = rol32(a, s))
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#define K1 0
20#define K2 013240474631UL
21#define K3 015666365641UL
22
23/*
24 * Basic cut-down MD4 transform. Returns only 32 bits of result.
25 */
26__u32 half_md4_transform(__u32 buf[4], __u32 const in[8])
27{
28 __u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
29
30 /* Round 1 */
31 ROUND(F, a, b, c, d, in[0] + K1, 3);
32 ROUND(F, d, a, b, c, in[1] + K1, 7);
33 ROUND(F, c, d, a, b, in[2] + K1, 11);
34 ROUND(F, b, c, d, a, in[3] + K1, 19);
35 ROUND(F, a, b, c, d, in[4] + K1, 3);
36 ROUND(F, d, a, b, c, in[5] + K1, 7);
37 ROUND(F, c, d, a, b, in[6] + K1, 11);
38 ROUND(F, b, c, d, a, in[7] + K1, 19);
39
40 /* Round 2 */
41 ROUND(G, a, b, c, d, in[1] + K2, 3);
42 ROUND(G, d, a, b, c, in[3] + K2, 5);
43 ROUND(G, c, d, a, b, in[5] + K2, 9);
44 ROUND(G, b, c, d, a, in[7] + K2, 13);
45 ROUND(G, a, b, c, d, in[0] + K2, 3);
46 ROUND(G, d, a, b, c, in[2] + K2, 5);
47 ROUND(G, c, d, a, b, in[4] + K2, 9);
48 ROUND(G, b, c, d, a, in[6] + K2, 13);
49
50 /* Round 3 */
51 ROUND(H, a, b, c, d, in[3] + K3, 3);
52 ROUND(H, d, a, b, c, in[7] + K3, 9);
53 ROUND(H, c, d, a, b, in[2] + K3, 11);
54 ROUND(H, b, c, d, a, in[6] + K3, 15);
55 ROUND(H, a, b, c, d, in[1] + K3, 3);
56 ROUND(H, d, a, b, c, in[5] + K3, 9);
57 ROUND(H, c, d, a, b, in[0] + K3, 11);
58 ROUND(H, b, c, d, a, in[4] + K3, 15);
59
60 buf[0] += a;
61 buf[1] += b;
62 buf[2] += c;
63 buf[3] += d;
64
65 return buf[1]; /* "most hashed" word */
66}
67EXPORT_SYMBOL(half_md4_transform);