EC_GFp_simple_method.3ossl - Man Page

Functions for obtaining EC_METHOD objects

Synopsis

 #include <openssl/ec.h>

Deprecated since OpenSSL 3.0:

 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

All const EC_METHOD *EC_GF* functions were deprecated in OpenSSL 3.0, since EC_METHOD is no longer a public concept.

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() was deprecated in OpenSSL 3.0. Applications should use EC_GROUP_get_field_type() as a replacement (see EC_GROUP_copy(3)).

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)

History

EC_GFp_simple_method(), EC_GFp_mont_method(void), EC_GFp_nist_method(), EC_GFp_nistp224_method(), EC_GFp_nistp256_method(), EC_GFp_nistp521_method(), EC_GF2m_simple_method(), and EC_METHOD_get_field_type() were deprecated in OpenSSL 3.0.

Referenced By

EC_GROUP_copy.3ossl(3), EC_GROUP_new.3ossl(3), EC_KEY_get_enc_flags.3ossl(3), EC_KEY_new.3ossl(3), ECPKParameters_print.3ossl(3), EC_POINT_add.3ossl(3), EC_POINT_new.3ossl(3).

The man pages EC_GF2m_simple_method.3ossl(3), EC_GFp_mont_method.3ossl(3), EC_GFp_nist_method.3ossl(3), EC_GFp_nistp224_method.3ossl(3), EC_GFp_nistp256_method.3ossl(3), EC_GFp_nistp521_method.3ossl(3) and EC_METHOD_get_field_type.3ossl(3) are aliases of EC_GFp_simple_method.3ossl(3).

2021-09-09 3.0.0 OpenSSL