=pod

=head1 NAME

X509_get_pubkey, X509_get0_pubkey, X509_set_pubkey, X509_get_X509_PUBKEY,
X509_REQ_get_pubkey, X509_REQ_set_pubkey, X509_REQ_get_X509_PUBKEY - get or
set certificate or certificate request public key.

=head1 SYNOPSIS

 #include <openssl/x509.h>

 EVP_PKEY *X509_get_pubkey(X509 *x);
 EVP_PKEY *X509_get0_pubkey(X509 *x);
 int X509_set_pubkey(X509 *x, EVP_PKEY *pkey);
 X509_PUBKEY *X509_get_X509_PUBKEY(X509 *x);

 EVP_PKEY *X509_REQ_get_pubkey(X509_REQ *req);
 int X509_REQ_set_pubkey(X509_REQ *x, EVP_PKEY *pkey);
 X509_PUBKEY *X509_REQ_get_X509_PUBKEY(X509_REQ *x);

=head1 DESCRIPTION

X509_get_pubkey() attempts to decode the public key for certificate B<x>. If
successful it returns the public key as an B<EVP_PKEY> pointer with its
reference count incremented: this means the returned key must be freed up
after use. X509_get0_pubkey() is similar except it does B<not> increment
the reference count of the returned B<EVP_PKEY> so it must not be freed up
after use.

X509_get_X509_PUBKEY() returns an internal pointer to the B<X509_PUBKEY>
structure which encodes the certificate of B<x>. The returned value
must not be freed up after use.

X509_set_pubkey() attempts to set the public key for certificate B<x> to
B<pkey>. The key B<pkey> should be freed up after use.

X509_REQ_get_pubkey(), X509_REQ_set_pubkey() and X509_REQ_get_X509_PUBKEY()
are similar but operate on certificate request B<req>.

=head1 NOTES

The first time a public key is decoded the B<EVP_PKEY> structure is
cached in the certificate or certificate request itself. Subsequent calls
return the cached structure with its reference count incremented to
improve performance.

=head1 RETURN VALUES

X509_get_pubkey(), X509_get0_pubkey(), X509_get_X509_PUBKEY(),
X509_REQ_get_pubkey() and X509_REQ_get_X509_PUBKEY() return a public key or
B<NULL> if an error occurred.

X509_set_pubkey() and X509_REQ_set_pubkey() rerturn 1 for success and 0
for failure.

=head1 SEE ALSO

L<d2i_X509(3)>,
L<ERR_get_error(3)>,
L<X509_CRL_get0_by_serial(3)>,
L<X509_get0_signature(3)>,
L<X509_get_ext_d2i(3)>,
L<X509_get_extension_flags(3)>,
L<X509_get_subject_name(3)>,
L<X509_get_version(3)>,
L<X509_NAME_add_entry_by_txt(3)>,
L<X509_NAME_ENTRY_get_object(3)>,
L<X509_NAME_get_index_by_NID(3)>,
L<X509_NAME_print_ex(3)>,
L<X509_new(3)>,
L<X509_sign(3)>,
L<X509V3_get_d2i(3)>,
L<X509_verify_cert(3)>

=head1 HISTORY

=cut