1=pod 2 3=head1 NAME 4 5EC_GFp_simple_method, EC_GFp_mont_method, EC_GFp_nist_method, EC_GFp_nistp224_method, EC_GFp_nistp256_method, EC_GFp_nistp521_method, EC_GF2m_simple_method, EC_METHOD_get_field_type - Functions for obtaining EC_METHOD objects 6 7=head1 SYNOPSIS 8 9 #include <openssl/ec.h> 10 11The following functions have been deprecated since OpenSSL 3.0, and can be 12hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value, 13see L<openssl_user_macros(7)>: 14 15 const EC_METHOD *EC_GFp_simple_method(void); 16 const EC_METHOD *EC_GFp_mont_method(void); 17 const EC_METHOD *EC_GFp_nist_method(void); 18 const EC_METHOD *EC_GFp_nistp224_method(void); 19 const EC_METHOD *EC_GFp_nistp256_method(void); 20 const EC_METHOD *EC_GFp_nistp521_method(void); 21 22 const EC_METHOD *EC_GF2m_simple_method(void); 23 24 int EC_METHOD_get_field_type(const EC_METHOD *meth); 25 26=head1 DESCRIPTION 27 28 29All const EC_METHOD *EC_GF* functions were deprecated in OpenSSL 3.0, since 30EC_METHOD is no longer a public concept. 31 32The Elliptic Curve library provides a number of different implementations through a single common interface. 33When constructing a curve using EC_GROUP_new (see L<EC_GROUP_new(3)>) an 34implementation method must be provided. The functions described here all return a const pointer to an 35B<EC_METHOD> structure that can be passed to EC_GROUP_NEW. It is important that the correct implementation 36type for the form of curve selected is used. 37 38For F2^m curves there is only one implementation choice, i.e. EC_GF2_simple_method. 39 40For Fp curves the lowest common denominator implementation is the EC_GFp_simple_method implementation. All 41other implementations are based on this one. EC_GFp_mont_method builds on EC_GFp_simple_method but adds the 42use of montgomery multiplication (see L<BN_mod_mul_montgomery(3)>). EC_GFp_nist_method 43offers an implementation optimised for use with NIST recommended curves (NIST curves are available through 44EC_GROUP_new_by_curve_name as described in L<EC_GROUP_new(3)>). 45 46The functions EC_GFp_nistp224_method, EC_GFp_nistp256_method and EC_GFp_nistp521_method offer 64 bit 47optimised implementations for the NIST P224, P256 and P521 curves respectively. Note, however, that these 48implementations are not available on all platforms. 49 50EC_METHOD_get_field_type() was deprecated in OpenSSL 3.0. 51Applications should use EC_GROUP_get_field_type() as a replacement (see L<EC_GROUP_copy(3)>). 52 53=head1 RETURN VALUES 54 55All EC_GFp* functions and EC_GF2m_simple_method always return a const pointer to an EC_METHOD structure. 56 57EC_METHOD_get_field_type returns an integer that identifies the type of field the EC_METHOD structure supports. 58 59=head1 SEE ALSO 60 61L<crypto(7)>, L<EC_GROUP_new(3)>, L<EC_GROUP_copy(3)>, 62L<EC_POINT_new(3)>, L<EC_POINT_add(3)>, L<EC_KEY_new(3)>, 63L<d2i_ECPKParameters(3)>, 64L<BN_mod_mul_montgomery(3)> 65 66=head1 HISTORY 67 68EC_GFp_simple_method(), EC_GFp_mont_method(void), 69EC_GFp_nist_method(), EC_GFp_nistp224_method(), 70EC_GFp_nistp256_method(), EC_GFp_nistp521_method(), 71EC_GF2m_simple_method(), and EC_METHOD_get_field_type() 72were deprecated in OpenSSL 3.0. 73 74=head1 COPYRIGHT 75 76Copyright 2013-2020 The OpenSSL Project Authors. All Rights Reserved. 77 78Licensed under the Apache License 2.0 (the "License"). You may not use 79this file except in compliance with the License. You can obtain a copy 80in the file LICENSE in the source distribution or at 81L<https://www.openssl.org/source/license.html>. 82 83=cut 84
