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Diffstat (limited to 'openssl-1.1.0h/doc/crypto/EC_GFp_simple_method.pod')
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diff --git a/openssl-1.1.0h/doc/crypto/EC_GFp_simple_method.pod b/openssl-1.1.0h/doc/crypto/EC_GFp_simple_method.pod new file mode 100644 index 0000000..f283d8e --- /dev/null +++ b/openssl-1.1.0h/doc/crypto/EC_GFp_simple_method.pod @@ -0,0 +1,69 @@ +=pod + +=head1 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 + +=head1 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); + +=head1 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 L<EC_GROUP_new(3)>) an +implementation method must be provided. The functions described here all return a const pointer to an +B<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 L<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 L<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 B<NID_X9_62_prime_field> is returned. If the field type is +F2^m then the value B<NID_X9_62_characteristic_two_field> is returned. These values are defined in the +obj_mac.h header file. + +=head1 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. + +=head1 SEE ALSO + +L<crypto(7)>, L<EC_GROUP_new(3)>, L<EC_GROUP_copy(3)>, +L<EC_POINT_new(3)>, L<EC_POINT_add(3)>, L<EC_KEY_new(3)>, +L<d2i_ECPKParameters(3)>, +L<BN_mod_mul_montgomery(3)> + +=head1 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 +L<https://www.openssl.org/source/license.html>. + +=cut |