Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/lib/halfmd4.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 2028 byte(s)
Tag kernel26-2.6.12-alx-r9
1 | #include <linux/kernel.h> |
2 | #include <linux/module.h> |
3 | #include <linux/cryptohash.h> |
4 | |
5 | /* F, G and H are basic MD4 functions: selection, majority, parity */ |
6 | #define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z)))) |
7 | #define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z))) |
8 | #define H(x, y, z) ((x) ^ (y) ^ (z)) |
9 | |
10 | /* |
11 | * The generic round function. The application is so specific that |
12 | * we don't bother protecting all the arguments with parens, as is generally |
13 | * good macro practice, in favor of extra legibility. |
14 | * Rotation is separate from addition to prevent recomputation |
15 | */ |
16 | #define ROUND(f, a, b, c, d, x, s) \ |
17 | (a += f(b, c, d) + x, a = (a << s) | (a >> (32 - s))) |
18 | #define K1 0 |
19 | #define K2 013240474631UL |
20 | #define K3 015666365641UL |
21 | |
22 | /* |
23 | * Basic cut-down MD4 transform. Returns only 32 bits of result. |
24 | */ |
25 | __u32 half_md4_transform(__u32 buf[4], __u32 const in[8]) |
26 | { |
27 | __u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3]; |
28 | |
29 | /* Round 1 */ |
30 | ROUND(F, a, b, c, d, in[0] + K1, 3); |
31 | ROUND(F, d, a, b, c, in[1] + K1, 7); |
32 | ROUND(F, c, d, a, b, in[2] + K1, 11); |
33 | ROUND(F, b, c, d, a, in[3] + K1, 19); |
34 | ROUND(F, a, b, c, d, in[4] + K1, 3); |
35 | ROUND(F, d, a, b, c, in[5] + K1, 7); |
36 | ROUND(F, c, d, a, b, in[6] + K1, 11); |
37 | ROUND(F, b, c, d, a, in[7] + K1, 19); |
38 | |
39 | /* Round 2 */ |
40 | ROUND(G, a, b, c, d, in[1] + K2, 3); |
41 | ROUND(G, d, a, b, c, in[3] + K2, 5); |
42 | ROUND(G, c, d, a, b, in[5] + K2, 9); |
43 | ROUND(G, b, c, d, a, in[7] + K2, 13); |
44 | ROUND(G, a, b, c, d, in[0] + K2, 3); |
45 | ROUND(G, d, a, b, c, in[2] + K2, 5); |
46 | ROUND(G, c, d, a, b, in[4] + K2, 9); |
47 | ROUND(G, b, c, d, a, in[6] + K2, 13); |
48 | |
49 | /* Round 3 */ |
50 | ROUND(H, a, b, c, d, in[3] + K3, 3); |
51 | ROUND(H, d, a, b, c, in[7] + K3, 9); |
52 | ROUND(H, c, d, a, b, in[2] + K3, 11); |
53 | ROUND(H, b, c, d, a, in[6] + K3, 15); |
54 | ROUND(H, a, b, c, d, in[1] + K3, 3); |
55 | ROUND(H, d, a, b, c, in[5] + K3, 9); |
56 | ROUND(H, c, d, a, b, in[0] + K3, 11); |
57 | ROUND(H, b, c, d, a, in[4] + K3, 15); |
58 | |
59 | buf[0] += a; |
60 | buf[1] += b; |
61 | buf[2] += c; |
62 | buf[3] += d; |
63 | |
64 | return buf[1]; /* "most hashed" word */ |
65 | } |
66 | EXPORT_SYMBOL(half_md4_transform); |