*
*/
+
+
#include <openssl/err.h>
#include "ec_lcl.h"
const EC_METHOD *meth;
EC_GROUP *ret;
- meth = EC_GFp_nist_method();
+#if defined(OPENSSL_BN_ASM_MONT)
+ /*
+ * This might appear controversial, but the fact is that generic
+ * prime method was observed to deliver better performance even
+ * for NIST primes on a range of platforms, e.g.: 60%-15%
+ * improvement on IA-64, ~25% on ARM, 30%-90% on P4, 20%-25%
+ * in 32-bit build and 35%--12% in 64-bit build on Core2...
+ * Coefficients are relative to optimized bn_nist.c for most
+ * intensive ECDSA verify and ECDH operations for 192- and 521-
+ * bit keys respectively. Choice of these boundary values is
+ * arguable, because the dependency of improvement coefficient
+ * from key length is not a "monotone" curve. For example while
+ * 571-bit result is 23% on ARM, 384-bit one is -1%. But it's
+ * generally faster, sometimes "respectfully" faster, sometimes
+ * "tolerably" slower... What effectively happens is that loop
+ * with bn_mul_add_words is put against bn_mul_mont, and the
+ * latter "wins" on short vectors. Correct solution should be
+ * implementing dedicated NxN multiplication subroutines for
+ * small N. But till it materializes, let's stick to generic
+ * prime method...
+ * <appro>
+ */
+ meth = EC_GFp_mont_method();
+#else
+ if (BN_nist_mod_func(p))
+ meth = EC_GFp_nist_method();
+ else
+ meth = EC_GFp_mont_method();
+#endif
ret = EC_GROUP_new(meth);
if (ret == NULL)
if (!EC_GROUP_set_curve_GFp(ret, p, a, b, ctx))
{
- unsigned long err;
-
- err = ERR_peek_last_error();
-
- if (!(ERR_GET_LIB(err) == ERR_LIB_EC &&
- ((ERR_GET_REASON(err) == EC_R_NOT_A_NIST_PRIME) ||
- (ERR_GET_REASON(err) == EC_R_NOT_A_SUPPORTED_NIST_PRIME))))
- {
- /* real error */
-
- EC_GROUP_clear_free(ret);
- return NULL;
- }
-
-
- /* not an actual error, we just cannot use EC_GFp_nist_method */
-
- ERR_clear_error();
-
EC_GROUP_clear_free(ret);
- meth = EC_GFp_mont_method();
-
- ret = EC_GROUP_new(meth);
- if (ret == NULL)
- return NULL;
-
- if (!EC_GROUP_set_curve_GFp(ret, p, a, b, ctx))
- {
- EC_GROUP_clear_free(ret);
- return NULL;
- }
+ return NULL;
}
return ret;