1#include <linux/compiler.h>
2#include <linux/export.h>
3#include <linux/cryptohash.h>
4#include <linux/bitops.h>
5
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)	\
18	(a += f(b, c, d) + x, a = rol32(a, s))
19#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);
68