early-access version 1255

externals/libressl/crypto/ec/ec_cvt.c

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+/* $OpenBSD: ec_cvt.c,v 1.6 2014/07/10 22:45:57 jsing Exp $ */
+/*
+ * Originally written by Bodo Moeller for the OpenSSL project.
+ */
+/* ====================================================================
+ * Copyright (c) 1998-2002 The OpenSSL Project.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ *    software must display the following acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com).  This product includes software written by Tim
+ * 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/opensslconf.h>
+
+#include <openssl/err.h>
+#include "ec_lcl.h"
+
+EC_GROUP *
+EC_GROUP_new_curve_GFp(const BIGNUM *p, const BIGNUM *a, const BIGNUM *b,
+    BN_CTX *ctx)
+{
+	const EC_METHOD *meth;
+	EC_GROUP *ret;
+
+#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