/* crypto/ec/ec_cvt.c */
+/*
+ * Originally written by Bodo Moeller for the OpenSSL project.
+ */
/* ====================================================================
* Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
*
* Hudson (tjh@cryptsoft.com).
*
*/
+/* ====================================================================
+ * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
+ *
+ * Portions of the attached software ("Contribution") are developed by
+ * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
+ *
+ * The Contribution is licensed pursuant to the OpenSSL open source
+ * license provided above.
+ *
+ * The elliptic curve binary polynomial software is originally written by
+ * Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems Laboratories.
+ *
+ */
+#include <openssl/err.h>
#include "ec_lcl.h"
{
const EC_METHOD *meth;
EC_GROUP *ret;
-
- /* Finally, this will use EC_GFp_nist_method if 'p' is a special
- * prime with optimized modular arithmetics (for NIST curves)
+
+#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
+ meth = EC_GFp_nist_method();
+#endif
ret = EC_GROUP_new(meth);
if (ret == NULL)
return 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 ret;
+ }
+
+#ifndef OPENSSL_NO_EC2M
+EC_GROUP *EC_GROUP_new_curve_GF2m(const BIGNUM *p, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
+ {
+ const EC_METHOD *meth;
+ EC_GROUP *ret;
+
+ meth = EC_GF2m_simple_method();
+
+ ret = EC_GROUP_new(meth);
+ if (ret == NULL)
+ return NULL;
+
+ if (!EC_GROUP_set_curve_GF2m(ret, p, a, b, ctx))
{
EC_GROUP_clear_free(ret);
return NULL;
return ret;
}
+#endif