• NAME
• SYNOPSIS
• DESCRIPTION
• RETURN VALUES
• SEE ALSO
• HISTORY
• COPYRIGHT

NAME

EC_GROUP_get0_order, EC_GROUP_order_bits, EC_GROUP_get0_cofactor, EC_GROUP_copy, EC_GROUP_dup, EC_GROUP_method_of, EC_GROUP_set_generator, EC_GROUP_get0_generator, EC_GROUP_get_order, EC_GROUP_get_cofactor, EC_GROUP_set_curve_name, EC_GROUP_get_curve_name, EC_GROUP_set_asn1_flag, EC_GROUP_get_asn1_flag, EC_GROUP_set_point_conversion_form, EC_GROUP_get_point_conversion_form, EC_GROUP_get0_seed, EC_GROUP_get_seed_len, EC_GROUP_set_seed, EC_GROUP_get_degree, EC_GROUP_check, EC_GROUP_check_named_curve, EC_GROUP_check_discriminant, EC_GROUP_cmp, EC_GROUP_get_basis_type, EC_GROUP_get_trinomial_basis, EC_GROUP_get_pentanomial_basis, EC_GROUP_get0_field - Functions for manipulating EC_GROUP objects

SYNOPSIS

 #include <openssl/ec.h>

 int EC_GROUP_copy(EC_GROUP *dst, const EC_GROUP *src);
 EC_GROUP *EC_GROUP_dup(const EC_GROUP *src);

 const EC_METHOD *EC_GROUP_method_of(const EC_GROUP *group);

 int EC_GROUP_set_generator(EC_GROUP *group, const EC_POINT *generator,
                            const BIGNUM *order, const BIGNUM *cofactor);
 const EC_POINT *EC_GROUP_get0_generator(const EC_GROUP *group);

 int EC_GROUP_get_order(const EC_GROUP *group, BIGNUM *order, BN_CTX *ctx);
 const BIGNUM *EC_GROUP_get0_order(const EC_GROUP *group);
 int EC_GROUP_order_bits(const EC_GROUP *group);
 int EC_GROUP_get_cofactor(const EC_GROUP *group, BIGNUM *cofactor, BN_CTX *ctx);
 const BIGNUM *EC_GROUP_get0_cofactor(const EC_GROUP *group);
 const BIGNUM *EC_GROUP_get0_field(const EC_GROUP *group);

 void EC_GROUP_set_curve_name(EC_GROUP *group, int nid);
 int EC_GROUP_get_curve_name(const EC_GROUP *group);

 void EC_GROUP_set_asn1_flag(EC_GROUP *group, int flag);
 int EC_GROUP_get_asn1_flag(const EC_GROUP *group);

 void EC_GROUP_set_point_conversion_form(EC_GROUP *group, point_conversion_form_t form);
 point_conversion_form_t EC_GROUP_get_point_conversion_form(const EC_GROUP *group);

 unsigned char *EC_GROUP_get0_seed(const EC_GROUP *x);
 size_t EC_GROUP_get_seed_len(const EC_GROUP *);
 size_t EC_GROUP_set_seed(EC_GROUP *, const unsigned char *, size_t len);

 int EC_GROUP_get_degree(const EC_GROUP *group);

 int EC_GROUP_check(const EC_GROUP *group, BN_CTX *ctx);
 int EC_GROUP_check_named_curve(const EC_GROUP *group, int nist_only,
                                BN_CTX *ctx);

 int EC_GROUP_check_discriminant(const EC_GROUP *group, BN_CTX *ctx);

 int EC_GROUP_cmp(const EC_GROUP *a, const EC_GROUP *b, BN_CTX *ctx);

 int EC_GROUP_get_basis_type(const EC_GROUP *);
 int EC_GROUP_get_trinomial_basis(const EC_GROUP *, unsigned int *k);
 int EC_GROUP_get_pentanomial_basis(const EC_GROUP *, unsigned int *k1,
                                    unsigned int *k2, unsigned int *k3);

DESCRIPTION

EC_GROUP_copy() copies the curve src into dst. Both src and dst must use the same EC_METHOD.

EC_GROUP_dup() creates a new EC_GROUP object and copies the content from src to the newly created EC_GROUP object.

EC_GROUP_method_of() obtains the EC_METHOD of group.

EC_GROUP_set_generator() sets curve parameters that must be agreed by all participants using the curve. These parameters include the generator, the order and the cofactor. The generator is a well defined point on the curve chosen for cryptographic operations. Integers used for point multiplications will be between 0 and n-1 where n is the order. The order multiplied by the cofactor gives the number of points on the curve.

EC_GROUP_get0_generator() returns the generator for the identified group.

EC_GROUP_get_order() retrieves the order of group and copies its value into order. It fails in case group is not fully initialized (i.e., its order is not set or set to zero).

EC_GROUP_get_cofactor() retrieves the cofactor of group and copies its value into cofactor. It fails in case group is not fully initialized or if the cofactor is not set (or set to zero).

The functions EC_GROUP_set_curve_name() and EC_GROUP_get_curve_name(), set and get the NID for the curve respectively (see RETURN VALUES

The following functions return 1 on success or 0 on error: EC_GROUP_copy(), EC_GROUP_set_generator(), EC_GROUP_check(), EC_GROUP_check_discriminant(), EC_GROUP_get_trinomial_basis() and EC_GROUP_get_pentanomial_basis().

EC_GROUP_new(3), EC_POINT_add(3), EC_GFp_simple_method(3), HISTORY

The EC_GROUP_check_named_curve() function was added in OpenSSL 3.0.

Licensed under the Apache License 2.0 (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.