=pod

=head1 NAME

EVP_PKEY_get_field_type, EVP_PKEY_get_ec_point_conv_form - get field type
or point conversion form of a key

=head1 SYNOPSIS

 #include <openssl/evp.h>

 int EVP_PKEY_get_field_type(const EVP_PKEY *pkey);
 int EVP_PKEY_get_ec_point_conv_form(const EVP_PKEY *pkey);

=head1 DESCRIPTION

EVP_PKEY_get_field_type() returns the field type NID of the I<pkey>, if
I<pkey>'s key type supports it. The types currently supported
by the built-in OpenSSL providers are either B<NID_X9_62_prime_field>
for prime curves or B<NID_X9_62_characteristic_two_field> for binary curves;
these values are defined in the F<< <openssl/obj_mac.h> >> header file.

EVP_PKEY_get_ec_point_conv_form() returns the point conversion format
of the I<pkey>, if I<pkey>'s key type supports it.

=head1 NOTES

Among the standard OpenSSL key types, this is only supported for EC and
SM2 keys.  Other providers may support this for additional key types.

=head1 RETURN VALUES

EVP_PKEY_get_field_type() returns the field type NID or 0 on error.

EVP_PKEY_get_ec_point_conv_form() returns the point conversion format number
(see L<EC_GROUP_copy(3)>) or 0 on error.

=head1 SEE ALSO

L<EC_GROUP_copy(3)>

=head1 HISTORY

These functions were added in OpenSSL 3.0.

=head1 COPYRIGHT

Copyright 2021 The OpenSSL Project Authors. All Rights Reserved.

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>.

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