From: Frederik Sdun <fs_1600@web.de>
To: linux-crypto@vger.kernel.org, herbert@gondor.apana.org.au,
davem@davemloft.net
Subject: [PATCH] crypto/aes.c remove operator ? and variable t in bf_setkey
Date: Mon, 16 Jul 2007 02:52:34 +0200 [thread overview]
Message-ID: <1184547154.23516.12.camel@localhost> (raw)
Hi,
this removes the the ? operator which is false nearly all the time.
--- aes.c.orig 2007-07-15 11:43:21.000000000 +0200
+++ aes.c 2007-07-16 01:56:49.000000000 +0200
@@ -156,9 +156,12 @@
p = (p << 1) ^ (p & 0x80 ? 0x01b : 0);
}
+
+ sbx_tab[0] = 0x63;
+ isb_tab[0x63] = (u8) 0;
- for (i = 0; i < 256; ++i) {
- p = (i ? pow_tab[255 - log_tab[i]] : 0);
+ for (i = 1; i < 256; ++i) {
+ p = pow_tab[255 - log_tab[i]];
q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2));
p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2));
sbx_tab[i] = p;
this removes the variable t which is only a working copy of p, but you
do not need a copy
@@ -135,7 +135,7 @@
static void __init
gen_tabs (void)
{
- u32 i, t;
+ u32 i;
u8 p, q;
/* log and power tables for GF(2**8) finite field with
@@ -168,38 +171,38 @@
for (i = 0; i < 256; ++i) {
p = sbx_tab[i];
- t = p;
- fl_tab[0][i] = t;
- fl_tab[1][i] = rol32(t, 8);
- fl_tab[2][i] = rol32(t, 16);
- fl_tab[3][i] = rol32(t, 24);
+
+ fl_tab[0][i] = p;
+ fl_tab[1][i] = rol32(p, 8);
+ fl_tab[2][i] = rol32(p, 16);
+ fl_tab[3][i] = rol32(p, 24);
- t = ((u32) ff_mult (2, p)) |
+ p = ((u32) ff_mult (2, p)) |
((u32) p << 8) |
((u32) p << 16) | ((u32) ff_mult (3, p) << 24);
- ft_tab[0][i] = t;
- ft_tab[1][i] = rol32(t, 8);
- ft_tab[2][i] = rol32(t, 16);
- ft_tab[3][i] = rol32(t, 24);
+ ft_tab[0][i] = p;
+ ft_tab[1][i] = rol32(p, 8);
+ ft_tab[2][i] = rol32(p, 16);
+ ft_tab[3][i] = rol32(p, 24);
p = isb_tab[i];
- t = p;
- il_tab[0][i] = t;
- il_tab[1][i] = rol32(t, 8);
- il_tab[2][i] = rol32(t, 16);
- il_tab[3][i] = rol32(t, 24);
+
+ il_tab[0][i] = p;
+ il_tab[1][i] = rol32(p, 8);
+ il_tab[2][i] = rol32(p, 16);
+ il_tab[3][i] = rol32(p, 24);
- t = ((u32) ff_mult (14, p)) |
+ p = ((u32) ff_mult (14, p)) |
((u32) ff_mult (9, p) << 8) |
((u32) ff_mult (13, p) << 16) |
((u32) ff_mult (11, p) << 24);
- it_tab[0][i] = t;
- it_tab[1][i] = rol32(t, 8);
- it_tab[2][i] = rol32(t, 16);
- it_tab[3][i] = rol32(t, 24);
+ it_tab[0][i] = p;
+ it_tab[1][i] = rol32(p, 8);
+ it_tab[2][i] = rol32(p, 16);
+ it_tab[3][i] = rol32(p, 24);
}
}
Frederik
next reply other threads:[~2007-07-16 0:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-16 0:52 Frederik Sdun [this message]
2007-07-16 3:28 ` [PATCH] crypto/aes.c remove operator ? and variable t in bf_setkey Herbert Xu
2007-07-16 13:15 ` Frederik Sdun
2007-07-17 12:35 ` Herbert Xu
2007-07-18 21:55 ` Frederik Sdun
2007-07-25 6:51 ` Herbert Xu
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