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(3), ec(3), 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)
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711.0.2k                            2017-01-26           EC_GFp_simple_method(3)
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