1EC_GFP_SIMPLE_METHOD(3)             OpenSSL            EC_GFP_SIMPLE_METHOD(3)
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NAME

6       EC_GFp_simple_method, EC_GFp_mont_method, EC_GFp_nist_method,
7       EC_GFp_nistp224_method, EC_GFp_nistp256_method, EC_GFp_nistp521_method,
8       EC_GF2m_simple_method, EC_METHOD_get_field_type - Functions for
9       obtaining EC_METHOD objects
10

SYNOPSIS

12        #include <openssl/ec.h>
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14        const EC_METHOD *EC_GFp_simple_method(void);
15        const EC_METHOD *EC_GFp_mont_method(void);
16        const EC_METHOD *EC_GFp_nist_method(void);
17        const EC_METHOD *EC_GFp_nistp224_method(void);
18        const EC_METHOD *EC_GFp_nistp256_method(void);
19        const EC_METHOD *EC_GFp_nistp521_method(void);
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21        const EC_METHOD *EC_GF2m_simple_method(void);
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23        int EC_METHOD_get_field_type(const EC_METHOD *meth);
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DESCRIPTION

26       The Elliptic Curve library provides a number of different
27       implementations through a single common interface.  When constructing a
28       curve using EC_GROUP_new (see EC_GROUP_new(3)) an implementation method
29       must be provided. The functions described here all return a const
30       pointer to an EC_METHOD structure that can be passed to EC_GROUP_NEW.
31       It is important that the correct implementation type for the form of
32       curve selected is used.
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34       For F2^m curves there is only one implementation choice, i.e.
35       EC_GF2_simple_method.
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37       For Fp curves the lowest common denominator implementation is the
38       EC_GFp_simple_method implementation. All other implementations are
39       based on this one. EC_GFp_mont_method builds on EC_GFp_simple_method
40       but adds the use of montgomery multiplication (see
41       BN_mod_mul_montgomery(3)). EC_GFp_nist_method offers an implementation
42       optimised for use with NIST recommended curves (NIST curves are
43       available through EC_GROUP_new_by_curve_name as described in
44       EC_GROUP_new(3)).
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46       The functions EC_GFp_nistp224_method, EC_GFp_nistp256_method and
47       EC_GFp_nistp521_method offer 64 bit optimised implementations for the
48       NIST P224, P256 and P521 curves respectively. Note, however, that these
49       implementations are not available on all platforms.
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51       EC_METHOD_get_field_type identifies what type of field the EC_METHOD
52       structure supports, which will be either F2^m or Fp. If the field type
53       is Fp then the value NID_X9_62_prime_field is returned. If the field
54       type is F2^m then the value NID_X9_62_characteristic_two_field is
55       returned. These values are defined in the obj_mac.h header file.
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RETURN VALUES

58       All EC_GFp* functions and EC_GF2m_simple_method always return a const
59       pointer to an EC_METHOD structure.
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61       EC_METHOD_get_field_type returns an integer that identifies the type of
62       field the EC_METHOD structure supports.
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SEE ALSO

65       crypto(7), EC_GROUP_new(3), EC_GROUP_copy(3), EC_POINT_new(3),
66       EC_POINT_add(3), EC_KEY_new(3), d2i_ECPKParameters(3),
67       BN_mod_mul_montgomery(3)
68

70       Copyright 2013-2017 The OpenSSL Project Authors. All Rights Reserved.
71
72       Licensed under the OpenSSL license (the "License").  You may not use
73       this file except in compliance with the License.  You can obtain a copy
74       in the file LICENSE in the source distribution or at
75       <https://www.openssl.org/source/license.html>.
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791.1.1c                            2019-05-28           EC_GFP_SIMPLE_METHOD(3)
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