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