|  | =pod | 
|  |  | 
|  | =head1 NAME | 
|  |  | 
|  | x509 - X.509 certificate handling | 
|  |  | 
|  | =head1 SYNOPSIS | 
|  |  | 
|  | #include <openssl/x509.h> | 
|  |  | 
|  | =head1 DESCRIPTION | 
|  |  | 
|  | A X.509 certificate is a structured grouping of information about | 
|  | an individual, a device, or anything one can imagine.  A X.509 CRL | 
|  | (certificate revocation list) is a tool to help determine if a | 
|  | certificate is still valid.  The exact definition of those can be | 
|  | found in the X.509 document from ITU-T, or in RFC3280 from PKIX. | 
|  | In OpenSSL, the type X509 is used to express such a certificate, and | 
|  | the type X509_CRL is used to express a CRL. | 
|  |  | 
|  | A related structure is a certificate request, defined in PKCS#10 from | 
|  | RSA Security, Inc, also reflected in RFC2896.  In OpenSSL, the type | 
|  | X509_REQ is used to express such a certificate request. | 
|  |  | 
|  | To handle some complex parts of a certificate, there are the types | 
|  | X509_NAME (to express a certificate name), X509_ATTRIBUTE (to express | 
|  | a certificate attributes), X509_EXTENSION (to express a certificate | 
|  | extension) and a few more. | 
|  |  | 
|  | Finally, there's the supertype X509_INFO, which can contain a CRL, a | 
|  | certificate and a corresponding private key. | 
|  |  | 
|  | B<X509_>I<...>, B<d2i_X509_>I<...> and B<i2d_X509_>I<...> handle X.509 | 
|  | certificates, with some exceptions, shown below. | 
|  |  | 
|  | B<X509_CRL_>I<...>, B<d2i_X509_CRL_>I<...> and B<i2d_X509_CRL_>I<...> | 
|  | handle X.509 CRLs. | 
|  |  | 
|  | B<X509_REQ_>I<...>, B<d2i_X509_REQ_>I<...> and B<i2d_X509_REQ_>I<...> | 
|  | handle PKCS#10 certificate requests. | 
|  |  | 
|  | B<X509_NAME_>I<...> handle certificate names. | 
|  |  | 
|  | B<X509_ATTRIBUTE_>I<...> handle certificate attributes. | 
|  |  | 
|  | B<X509_EXTENSION_>I<...> handle certificate extensions. | 
|  |  | 
|  | =head1 SEE ALSO | 
|  |  | 
|  | L<X509_NAME_ENTRY_get_object(3)|X509_NAME_ENTRY_get_object(3)>, | 
|  | L<X509_NAME_add_entry_by_txt(3)|X509_NAME_add_entry_by_txt(3)>, | 
|  | L<X509_NAME_add_entry_by_NID(3)|X509_NAME_add_entry_by_NID(3)>, | 
|  | L<X509_NAME_print_ex(3)|X509_NAME_print_ex(3)>, | 
|  | L<X509_NAME_new(3)|X509_NAME_new(3)>, | 
|  | L<d2i_X509(3)|d2i_X509(3)>, | 
|  | L<d2i_X509_ALGOR(3)|d2i_X509_ALGOR(3)>, | 
|  | L<d2i_X509_CRL(3)|d2i_X509_CRL(3)>, | 
|  | L<d2i_X509_NAME(3)|d2i_X509_NAME(3)>, | 
|  | L<d2i_X509_REQ(3)|d2i_X509_REQ(3)>, | 
|  | L<d2i_X509_SIG(3)|d2i_X509_SIG(3)>, | 
|  | L<crypto(3)|crypto(3)>, | 
|  | L<x509v3(3)|x509v3(3)> | 
|  |  | 
|  | =cut |