diff options
author | Bodo Möller <bodo@openssl.org> | 2001-03-20 11:16:12 +0000 |
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committer | Bodo Möller <bodo@openssl.org> | 2001-03-20 11:16:12 +0000 |
commit | 26fbabf3d1c52c1e275faa5ae5c9c72b7b0bc0b4 (patch) | |
tree | 9fd083c9d974a8e580bed38f3fdba2e1b4caa5fd /crypto/ec | |
parent | 37cdcb4d8a875e40f93a35749dff6bbe10cf6733 (diff) |
Increase boundaries in EC_window_bits_for_scalar_size table.
Diffstat (limited to 'crypto/ec')
-rw-r--r-- | crypto/ec/ec_mult.c | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/crypto/ec/ec_mult.c b/crypto/ec/ec_mult.c index d1478740a3..27e9aadd67 100644 --- a/crypto/ec/ec_mult.c +++ b/crypto/ec/ec_mult.c @@ -64,10 +64,10 @@ #define EC_window_bits_for_scalar_size(b) \ - ((b) >= 1500 ? 6 : \ - (b) >= 550 ? 5 : \ - (b) >= 200 ? 4 : \ - (b) >= 55 ? 3 : \ + ((b) >= 2000 ? 6 : \ + (b) >= 800 ? 5 : \ + (b) >= 300 ? 4 : \ + (b) >= 70 ? 3 : \ (b) >= 20 ? 2 : \ 1) /* For window size 'w' (w >= 2), we compute the odd multiples @@ -126,17 +126,20 @@ * w = 1 if 12 >= b * * Note that neither table tries to take into account memory usage - * (code locality etc.). Actual timings with NIST curve P-192 and - * 192-bit scalars show that w = 3 (instead of 4) is preferrable; - * and timings with NIST curve P-521 and 521-bit scalars show that - * w = 4 (instead of 5) is preferrable. So we round up all the + * (allocation overhead, code locality etc.). Actual timings with + * NIST curves P-192, P-224, and P-256 with scalars of 192, 224, + * and 256 bits, respectively, show that w = 3 (instead of 4) is + * preferrable; timings with NIST curve P-384 and 384-bit scalars + * confirm that w = 4 is optimal for this case; and timings with + * NIST curve P-521 and 521-bit scalars show that w = 4 (instead + * of 5) is preferrable. So we generously round up all the * boundaries and use the following table: * - * w >= 6 if b >= 1500 - * w = 5 if 1499 >= b >= 550 - * w = 4 if 549 >= b >= 200 - * w = 3 if 199 >= b >= 55 - * w = 2 if 54 >= b >= 20 + * w >= 6 if b >= 2000 + * w = 5 if 1999 >= b >= 800 + * w = 4 if 799 >= b >= 300 + * w = 3 if 299 >= b >= 70 + * w = 2 if 69 >= b >= 20 * w = 1 if 19 >= b */ @@ -282,7 +285,7 @@ int EC_POINTs_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar, } } -#if 1 /* optional, maybe we should only do this if total_num > 1 */ +#if 1 /* optional; EC_window_bits_for_scalar_size assumes we do this step */ if (!EC_POINTs_make_affine(group, num_val, val, ctx)) goto err; #endif |