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_discriminant, EC_GROUP_cmp,
+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_get_pentanomial_basis, EC_GROUP_get0_field
- Functions for manipulating EC_GROUP objects
=head1 SYNOPSIS
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);
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);
int EC_GROUP_check_discriminant(const EC_GROUP *group, BN_CTX *ctx);
named curve NID set. If asn1_flags is B<OPENSSL_EC_EXPLICIT_CURVE> the
parameters are explicitly encoded. The functions EC_GROUP_get_asn1_flag and
EC_GROUP_set_asn1_flag get and set the status of the asn1_flag for the curve.
-Note: B<OPENSSL_EC_EXPLICIT_CURVE> was first added to OpenSSL 1.1.0, for
+Note: B<OPENSSL_EC_EXPLICIT_CURVE> was added in OpenSSL 1.1.0, for
previous versions of OpenSSL the value 0 must be used instead. Before OpenSSL
1.1.0 the default form was to use explicit parameters (meaning that
applications would have to explicitly set the named curve form) in OpenSSL
If the seed is present for a curve then the b parameter was generated in a verifiable fashion using that seed. The OpenSSL EC library
does not use this seed value but does enable you to inspect it using EC_GROUP_get0_seed. This returns a pointer to a memory block
containing the seed that was used. The length of the memory block can be obtained using EC_GROUP_get_seed_len. A number of the
-builtin curves within the library provide seed values that can be obtained. It is also possible to set a custom seed using
+built-in curves within the library provide seed values that can be obtained. It is also possible to set a custom seed using
EC_GROUP_set_seed and passing a pointer to a memory block, along with the length of the seed. Again, the EC library will not use
this seed value, although it will be preserved in any ASN1 based communications.
verifying that the discriminant is non zero; that a generator has been defined; that the generator is on the curve and has
the correct order.
+The function EC_GROUP_check_named_curve determines if the group's domain parameters match one of the built-in curves supported by the library.
+The curve name is returned as a B<NID> if it matches. If the group's domain parameters have been modified then no match will be found.
+If the curve name of the given group is B<NID_undef> (e.g. it has been created by using explicit parameters with no curve name),
+then this method can be used to lookup the name of the curve that matches the group domain parameters. The built-in curves contain
+aliases, so that multiple NID's can map to the same domain parameters. For such curves it is unspecified which of the aliases will be
+returned if the curve name of the given group is NID_undef.
+If B<nist_only> is 1 it will only look for NIST approved curves, otherwise it searches all built-in curves.
+
EC_GROUP_cmp compares B<a> and B<b> to determine whether they represent the same curve or not.
The functions EC_GROUP_get_basis_type, EC_GROUP_get_trinomial_basis and EC_GROUP_get_pentanomial_basis should only be called for curves
and EC_GROUP_get_degree return the order, cofactor, curve name (NID), ASN1 flag, point_conversion_form and degree for the
specified curve respectively. If there is no curve name associated with a curve then EC_GROUP_get_curve_name will return 0.
+EC_GROUP_check_named_curve() returns the nid of the matching named curve, otherwise it returns 0 for no match, or -1 on error.
+
EC_GROUP_get0_order() returns an internal pointer to the group order.
-EC_GROUP_get_order_bits() returns the number of bits in the group order.
+EC_GROUP_order_bits() returns the number of bits in the group order.
EC_GROUP_get0_cofactor() returns an internal pointer to the group cofactor.
+EC_GROUP_get0_field() returns an internal pointer to the group field. For curves over GF(p), this is the modulus; for curves
+over GF(2^m), this is the irreducible polynomial defining the field.
EC_GROUP_get0_seed returns a pointer to the seed that was used to generate the parameter b, or NULL if the seed is not
specified. EC_GROUP_get_seed_len returns the length of the seed or 0 if the seed is not specified.
L<EC_POINT_new(3)>, L<EC_POINT_add(3)>, L<EC_KEY_new(3)>,
L<EC_GFp_simple_method(3)>, L<d2i_ECPKParameters(3)>
+=head1 HISTORY
+
+The EC_GROUP_check_named_curve() function was added in OpenSSL 3.0.
+
=head1 COPYRIGHT
-Copyright 2013-2017 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2013-2019 The OpenSSL Project Authors. All Rights Reserved.
-Licensed under the OpenSSL license (the "License"). You may not use
+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
L<https://www.openssl.org/source/license.html>.
projects / openssl.git / blobdiff