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Subject[PATCH] cryptoapi: "rolled" SHA1
A "rolled" version of SHA1 similar to that in /dev/random. About 1/4th
the size of the unrolled versions and 2/3 the speed (after factoring
out cryptoapi overhead). This also simplifies some of the magic hash
function macros.

diff -urN -X dontdiff orig/crypto/sha1.c work/crypto/sha1.c
--- orig/crypto/sha1.c 2003-07-13 22:32:29.000000000 -0500
+++ work/crypto/sha1.c 2003-08-12 18:51:49.000000000 -0500
@@ -32,6 +32,18 @@
return (((value) << (bits)) | ((value) >> (32 - (bits))));
}

+/* The SHA Mysterious Constants */
+
+#define K1 0x5A827999L /* Rounds 0-19: sqrt(2) * 2^30 */
+#define K2 0x6ED9EBA1L /* Rounds 20-39: sqrt(3) * 2^30 */
+#define K3 0x8F1BBCDCL /* Rounds 40-59: sqrt(5) * 2^30 */
+#define K4 0xCA62C1D6L /* Rounds 60-79: sqrt(10) * 2^30 */
+
+#define f1(x,y,z) ( z ^ (x & (y^z)) ) /* Rounds 0-19: x ? y : z */
+#define f2(x,y,z) (x ^ y ^ z) /* Rounds 20-39: XOR */
+#define f3(x,y,z) ( (x & y) + (z & (x ^ y)) ) /* Rounds 40-59: majority */
+#define f4(x,y,z) (x ^ y ^ z) /* Rounds 60-79: XOR */
+
/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */
# define blk0(i) block32[i]
@@ -40,14 +52,11 @@
^block32[(i+2)&15]^block32[i&15],1))

/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
-#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5); \
- w=rol(w,30);
-#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5); \
- w=rol(w,30);
-#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
-#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5); \
- w=rol(w,30);
-#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);
+#define R0(v,w,x,y,z,i) z+=f1(w,x,y)+blk0(i)+K1+rol(v,5); w=rol(w,30);
+#define R1(v,w,x,y,z,i) z+=f1(w,x,y) +blk(i)+K1+rol(v,5); w=rol(w,30);
+#define R2(v,w,x,y,z,i) z+=f2(w,x,y) +blk(i)+K2+rol(v,5); w=rol(w,30);
+#define R3(v,w,x,y,z,i) z+=f3(w,x,y) +blk(i)+K3+rol(v,5); w=rol(w,30);
+#define R4(v,w,x,y,z,i) z+=f4(w,x,y) +blk(i)+K4+rol(v,5); w=rol(w,30);

struct sha1_ctx {
u64 count;
@@ -55,6 +64,61 @@
u8 buffer[64];
};

+#if 1
+/* Hash a single 512-bit block. This is the core of the algorithm. */
+static void sha1_transform(u32 *state, const u8 *in)
+{
+ u32 a, b, c, d, e, i, t;
+ u32 buf[80];
+
+ /* convert/copy data to workspace */
+ for (a = 0; a < 16; a++)
+ buf[a] = be32_to_cpu (((const u32 *)in)[a]);
+
+ /* preliminary expansion of 16 to 80 words */
+
+ for (i = 0; i < 64; i++) {
+ a = buf[i] ^ buf[i+2] ^ buf[i+8] ^ buf[i+13];
+ buf[i+16] = rol(a, 1);
+ }
+
+ /* Set up first buffer and local data buffer */
+ a = state[0];
+ b = state[1];
+ c = state[2];
+ d = state[3];
+ e = state[4];
+
+ /* Heavy mangling, in 4 sub-rounds of 20 iterations each. */
+
+ for (i = 0; i < 80; i++) {
+ if (i < 40) {
+ if (i < 20)
+ t = f1(b, c, d) + K1;
+ else
+ t = f2(b, c, d) + K2;
+ } else {
+ if (i < 60)
+ t = f3(b, c, d) + K3;
+ else
+ t = f4(b, c, d) + K4;
+ }
+ t += rol(a, 5) + e + buf[i];
+ e = d; d = c; c = rol(b, 30); b = a; a = t;
+ }
+
+ /* Add the working vars back into context.state[] */
+ state[0] += a;
+ state[1] += b;
+ state[2] += c;
+ state[3] += d;
+ state[4] += e;
+
+ /* Wipe variables */
+ a = b = c = d = e = 0;
+ memset (buf, 0x00, sizeof buf);
+}
+#else
/* Hash a single 512-bit block. This is the core of the algorithm. */
static void sha1_transform(u32 *state, const u8 *in)
{
@@ -103,6 +167,7 @@
a = b = c = d = e = 0;
memset (block32, 0x00, sizeof block32);
}
+#endif

static void sha1_init(void *ctx)
{
--
Matt Mackall : http://www.selenic.com : of or relating to the moon
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