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authorDenys Vlasenko2021-11-28 11:10:00 +0100
committerDenys Vlasenko2021-11-28 11:15:34 +0100
commitcfb615781df5c7439fe0060a85e6b6a56d10dc7f (patch)
treeebe1994c221f733ac1d42b02b3f4e71ad37946ad
parentbfefa6ab6cf30507009cca7182c7302900fb5534 (diff)
downloadbusybox-cfb615781df5c7439fe0060a85e6b6a56d10dc7f.zip
busybox-cfb615781df5c7439fe0060a85e6b6a56d10dc7f.tar.gz
tls: P256: simplify sp_256_mont_inv_8 (no need for a temporary)
function old new delta sp_256_ecc_mulmod_8 543 517 -26 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--networking/tls_sp_c32.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/networking/tls_sp_c32.c b/networking/tls_sp_c32.c
index 37e1cfa..9bd5c68 100644
--- a/networking/tls_sp_c32.c
+++ b/networking/tls_sp_c32.c
@@ -938,7 +938,7 @@ static void sp_256_mont_sqr_8(sp_digit* r, const sp_digit* a
/* Invert the number, in Montgomery form, modulo the modulus (prime) of the
* P256 curve. (r = 1 / a mod m)
*
- * r Inverse result.
+ * r Inverse result. Must not coincide with a.
* a Number to invert.
*/
#if 0
@@ -952,17 +952,15 @@ static void sp_256_mont_sqr_8(sp_digit* r, const sp_digit* a
#endif
static void sp_256_mont_inv_8(sp_digit* r, sp_digit* a)
{
- sp_digit t[8];
int i;
- memcpy(t, a, sizeof(sp_digit) * 8);
+ memcpy(r, a, sizeof(sp_digit) * 8);
for (i = 254; i >= 0; i--) {
- sp_256_mont_sqr_8(t, t /*, p256_mod, p256_mp_mod*/);
+ sp_256_mont_sqr_8(r, r /*, p256_mod, p256_mp_mod*/);
/*if (p256_mod_2[i / 32] & ((sp_digit)1 << (i % 32)))*/
if (i >= 224 || i == 192 || (i <= 95 && i != 1))
- sp_256_mont_mul_8(t, t, a /*, p256_mod, p256_mp_mod*/);
+ sp_256_mont_mul_8(r, r, a /*, p256_mod, p256_mp_mod*/);
}
- memcpy(r, t, sizeof(sp_digit) * 8);
}
/* Multiply a number by Montogmery normalizer mod modulus (prime).