diff options
| -rw-r--r-- | networking/tls_sp_c32.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/networking/tls_sp_c32.c b/networking/tls_sp_c32.c index c71f716..97b2d3d 100644 --- a/networking/tls_sp_c32.c +++ b/networking/tls_sp_c32.c @@ -554,11 +554,18 @@ static void sp_256_mont_sqr_10(sp_digit* r, const sp_digit* a, const sp_digit* m * r Inverse result. * a Number to invert. */ +#if 0 /* Mod-2 for the P256 curve. */ static const uint32_t p256_mod_2[8] = { 0xfffffffd,0xffffffff,0xffffffff,0x00000000, 0x00000000,0x00000000,0x00000001,0xffffffff, }; +//Bit pattern: +//2 2 2 2 2 2 2 1...1 +//5 5 4 3 2 1 0 9...0 9...1 +//543210987654321098765432109876543210987654321098765432109876543210...09876543210...09876543210 +//111111111111111111111111111111110000000000000000000000000000000100...00000111111...11111111101 +#endif static void sp_256_mont_inv_10(sp_digit* r, sp_digit* a) { sp_digit t[2*10]; //can be just [10]? @@ -567,7 +574,8 @@ static void sp_256_mont_inv_10(sp_digit* r, sp_digit* a) memcpy(t, a, sizeof(sp_digit) * 10); for (i = 254; i >= 0; i--) { sp_256_mont_sqr_10(t, t, p256_mod, p256_mp_mod); - if (p256_mod_2[i / 32] & ((sp_digit)1 << (i % 32))) + /*if (p256_mod_2[i / 32] & ((sp_digit)1 << (i % 32)))*/ + if (i >= 224 || i == 192 || (i <= 95 && i != 1)) sp_256_mont_mul_10(t, t, a, p256_mod, p256_mp_mod); } memcpy(r, t, sizeof(sp_digit) * 10); |