1 /*
2 * Copyright 2001-2021 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
4 *
5 * Licensed under the Apache License 2.0 (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 /*
12 * ECDSA low level APIs are deprecated for public use, but still ok for
13 * internal use.
14 */
15 #include "internal/deprecated.h"
16
17 #include <openssl/err.h>
18 #include "crypto/bn.h"
19 #include "ec_local.h"
20
EC_GROUP_new_curve_GFp(const BIGNUM * p,const BIGNUM * a,const BIGNUM * b,BN_CTX * ctx)21 EC_GROUP *EC_GROUP_new_curve_GFp(const BIGNUM *p, const BIGNUM *a,
22 const BIGNUM *b, BN_CTX *ctx)
23 {
24 const EC_METHOD *meth;
25 EC_GROUP *ret;
26
27 #if defined(OPENSSL_BN_ASM_MONT)
28 /*
29 * This might appear controversial, but the fact is that generic
30 * prime method was observed to deliver better performance even
31 * for NIST primes on a range of platforms, e.g.: 60%-15%
32 * improvement on IA-64, ~25% on ARM, 30%-90% on P4, 20%-25%
33 * in 32-bit build and 35%--12% in 64-bit build on Core2...
34 * Coefficients are relative to optimized bn_nist.c for most
35 * intensive ECDSA verify and ECDH operations for 192- and 521-
36 * bit keys respectively. Choice of these boundary values is
37 * arguable, because the dependency of improvement coefficient
38 * from key length is not a "monotone" curve. For example while
39 * 571-bit result is 23% on ARM, 384-bit one is -1%. But it's
40 * generally faster, sometimes "respectfully" faster, sometimes
41 * "tolerably" slower... What effectively happens is that loop
42 * with bn_mul_add_words is put against bn_mul_mont, and the
43 * latter "wins" on short vectors. Correct solution should be
44 * implementing dedicated NxN multiplication subroutines for
45 * small N. But till it materializes, let's stick to generic
46 * prime method...
47 * <appro>
48 */
49 meth = EC_GFp_mont_method();
50 #else
51 if (BN_nist_mod_func(p))
52 meth = EC_GFp_nist_method();
53 else
54 meth = EC_GFp_mont_method();
55 #endif
56
57 ret = ossl_ec_group_new_ex(ossl_bn_get_libctx(ctx), NULL, meth);
58 if (ret == NULL)
59 return NULL;
60
61 if (!EC_GROUP_set_curve(ret, p, a, b, ctx)) {
62 EC_GROUP_free(ret);
63 return NULL;
64 }
65
66 return ret;
67 }
68
69 #ifndef OPENSSL_NO_EC2M
EC_GROUP_new_curve_GF2m(const BIGNUM * p,const BIGNUM * a,const BIGNUM * b,BN_CTX * ctx)70 EC_GROUP *EC_GROUP_new_curve_GF2m(const BIGNUM *p, const BIGNUM *a,
71 const BIGNUM *b, BN_CTX *ctx)
72 {
73 const EC_METHOD *meth;
74 EC_GROUP *ret;
75
76 meth = EC_GF2m_simple_method();
77
78 ret = ossl_ec_group_new_ex(ossl_bn_get_libctx(ctx), NULL, meth);
79 if (ret == NULL)
80 return NULL;
81
82 if (!EC_GROUP_set_curve(ret, p, a, b, ctx)) {
83 EC_GROUP_free(ret);
84 return NULL;
85 }
86
87 return ret;
88 }
89 #endif
90
