Version:  2.6.24 2.6.25 2.6.26 2.6.27 2.6.28

Architecture:  x86 m68k m68knommu mips powerpc sh blackfin

Linux/lib/halfmd4.c

  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);
 67

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