1 /*
2 * Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
4 *
5 * Licensed under the OpenSSL license (the "License"). You may not use
6 * this file except in compliance with the License. You can obtain a copy
7 * in the file LICENSE in the source distribution or at
8 * https://www.openssl.org/source/license.html
9 */
10
11 #include <openssl/err.h>
12 #include "ec_local.h"
13
EC_GROUP_new_curve_GFp(const BIGNUM * p,const BIGNUM * a,const BIGNUM * b,BN_CTX * ctx)14 EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p, const BIGNUM *a,
15 const BIGNUM *b, BN_CTX *ctx)
16 {
17 const EC_METHOD *meth;
18 EC_GROUP *ret;
19
20 #if defined(OPENSSL_BN_ASM_MONT)
21 /*
22 * This might appear controversial, but the fact is that generic
23 * prime method was observed to deliver better performance even
24 * for NIST primes on a range of platforms, e.g.: 60%-15%
25 * improvement on IA-64, ~25% on ARM, 30%-90% on P4, 20%-25%
26 * in 32-bit build and 35%--12% in 64-bit build on Core2...
27 * Coefficients are relative to optimized bn_nist.c for most
28 * intensive ECDSA verify and ECDH operations for 192- and 521-
29 * bit keys respectively. Choice of these boundary values is
30 * arguable, because the dependency of improvement coefficient
31 * from key length is not a "monotone" curve. For example while
32 * 571-bit result is 23% on ARM, 384-bit one is -1%. But it's
33 * generally faster, sometimes "respectfully" faster, sometimes
34 * "tolerably" slower... What effectively happens is that loop
35 * with bn_mul_add_words is put against bn_mul_mont, and the
36 * latter "wins" on short vectors. Correct solution should be
37 * implementing dedicated NxN multiplication subroutines for
38 * small N. But till it materializes, let's stick to generic
39 * prime method...
40 * <appro>
41 */
42 meth = EC_GFp_mont_method();
43 #else
44 if (BN_nist_mod_func(p))
45 meth = EC_GFp_nist_method();
46 else
47 meth = EC_GFp_mont_method();
48 #endif
49
50 ret = EC_GROUP_new(meth);
51 if (ret == NULL)
52 return NULL;
53
54 if (!EC_GROUP_set_curve(ret, p, a, b, ctx)) {
55 EC_GROUP_clear_free(ret);
56 return NULL;
57 }
58
59 return ret;
60 }
61
62 #ifndef OPENSSL_NO_EC2M
EC_GROUP_new_curve_GF2m(const BIGNUM * p,const BIGNUM * a,const BIGNUM * b,BN_CTX * ctx)63 EC_GROUP *EC_GROUP_new_curve_GF2m(const BIGNUM *p, const BIGNUM *a,
64 const BIGNUM *b, BN_CTX *ctx)
65 {
66 const EC_METHOD *meth;
67 EC_GROUP *ret;
68
69 meth = EC_GF2m_simple_method();
70
71 ret = EC_GROUP_new(meth);
72 if (ret == NULL)
73 return NULL;
74
75 if (!EC_GROUP_set_curve(ret, p, a, b, ctx)) {
76 EC_GROUP_clear_free(ret);
77 return NULL;
78 }
79
80 return ret;
81 }
82 #endif
83