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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /lib/halfmd4.c
downloadlinux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'lib/halfmd4.c')
-rw-r--r--lib/halfmd4.c66
1 files changed, 66 insertions, 0 deletions
diff --git a/lib/halfmd4.c b/lib/halfmd4.c
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index 00000000000..e11db26f8ae
--- /dev/null
+++ b/lib/halfmd4.c
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+#include <linux/kernel.h>
+#include <linux/module.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);