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EC_GFp_simple_method(3)             OpenSSL            EC_GFp_simple_method(3)



NAME
       EC_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

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/ec.h>

        const EC_METHOD *EC_GFp_simple_method(void);
        const EC_METHOD *EC_GFp_mont_method(void);
        const EC_METHOD *EC_GFp_nist_method(void);
        const EC_METHOD *EC_GFp_nistp224_method(void);
        const EC_METHOD *EC_GFp_nistp256_method(void);
        const EC_METHOD *EC_GFp_nistp521_method(void);

        const EC_METHOD *EC_GF2m_simple_method(void);

        int EC_METHOD_get_field_type(const EC_METHOD *meth);

DESCRIPTION
       The Elliptic Curve library provides a number of different
       implementations through a single common interface.  When constructing a
       curve using EC_GROUP_new (see EC_GROUP_new(3)) an implementation method
       must be provided. The functions described here all return a const
       pointer to an EC_METHOD structure that can be passed to EC_GROUP_NEW.
       It is important that the correct implementation type for the form of
       curve selected is used.

       For F2^m curves there is only one implementation choice, i.e.
       EC_GF2_simple_method.

       For Fp curves the lowest common denominator implementation is the
       EC_GFp_simple_method implementation. All other implementations are
       based on this one. EC_GFp_mont_method builds on EC_GFp_simple_method
       but adds the use of montgomery multiplication (see
       BN_mod_mul_montgomery(3)). EC_GFp_nist_method offers an implementation
       optimised for use with NIST recommended curves (NIST curves are
       available through EC_GROUP_new_by_curve_name as described in
       EC_GROUP_new(3)).

       The functions EC_GFp_nistp224_method, EC_GFp_nistp256_method and
       EC_GFp_nistp521_method offer 64 bit optimised implementations for the
       NIST P224, P256 and P521 curves respectively. Note, however, that these
       implementations are not available on all platforms.

       EC_METHOD_get_field_type identifies what type of field the EC_METHOD
       structure supports, which will be either F2^m or Fp. If the field type
       is Fp then the value NID_X9_62_prime_field is returned. If the field
       type is F2^m then the value NID_X9_62_characteristic_two_field is
       returned. These values are defined in the obj_mac.h header file.

RETURN VALUES
       All EC_GFp* functions and EC_GF2m_simple_method always return a const
       pointer to an EC_METHOD structure.

       EC_METHOD_get_field_type returns an integer that identifies the type of
       field the EC_METHOD structure supports.

SEE ALSO
       crypto(7), EC_GROUP_new(3), EC_GROUP_copy(3), EC_POINT_new(3),
       EC_POINT_add(3), EC_KEY_new(3), d2i_ECPKParameters(3),
       BN_mod_mul_montgomery(3)

COPYRIGHT
       Copyright 2013-2017 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.



1.1.1                             2018-09-17           EC_GFp_simple_method(3)