NAME

     krb5_mk_req, krb5_mk_req_exact, krb5_mk_req_extended, krb5_rd_req, krb5_rd_req_with_keyblock, krb5_mk_rep,
     krb5_mk_rep_exact, krb5_mk_rep_extended, krb5_rd_rep, krb5_build_ap_req, krb5_verify_ap_req — create and
     read application authentication request

LIBRARY

     Kerberos 5 Library (libkrb5, -lkrb5)

SYNOPSIS

     #include <krb5.h>

     krb5_error_code
     krb5_mk_req(krb5_context context, krb5_auth_context *auth_context, const krb5_flags ap_req_options,
         const char *service, const char *hostname, krb5_data *in_data, krb5_ccache ccache, krb5_data *outbuf);

     krb5_error_code
     krb5_mk_req_extended(krb5_context context, krb5_auth_context *auth_context,
         const krb5_flags ap_req_options, krb5_data *in_data, krb5_creds *in_creds, krb5_data *outbuf);

     krb5_error_code
     krb5_rd_req(krb5_context context, krb5_auth_context *auth_context, const krb5_data *inbuf,
         krb5_const_principal server, krb5_keytab keytab, krb5_flags *ap_req_options, krb5_ticket **ticket);

     krb5_error_code
     krb5_build_ap_req(krb5_context context, krb5_enctype enctype, krb5_creds *cred, krb5_flags ap_options,
         krb5_data authenticator, krb5_data *retdata);

     krb5_error_code
     krb5_verify_ap_req(krb5_context context, krb5_auth_context *auth_context, krb5_ap_req *ap_req,
         krb5_const_principal server, krb5_keyblock *keyblock, krb5_flags flags, krb5_flags *ap_req_options,
         krb5_ticket **ticket);

DESCRIPTION

     The functions documented in this manual page document the functions that facilitates the exchange between a
     Kerberos client and server.  They are the core functions used in the authentication exchange between the
     client and the server.

     The krb5_mk_req and krb5_mk_req_extended creates the Kerberos message KRB_AP_REQ that is sent from the
     client to the server as the first packet in a client/server exchange.  The result that should be sent to
     server is stored in outbuf.

     auth_context should be allocated with krb5_auth_con_init() or NULL passed in, in that case, it will be
     allocated and freed internally.

     The input data in_data will have a checksum calculated over it and checksum will be transported in the
     message to the server.

     ap_req_options can be set to one or more of the following flags:

     AP_OPTS_USE_SESSION_KEY
             Use the session key when creating the request, used for user to user authentication.

     AP_OPTS_MUTUAL_REQUIRED
             Mark the request as mutual authenticate required so that the receiver returns a mutual
             authentication packet.

     The krb5_rd_req read the AP_REQ in inbuf and verify and extract the content.  If server is specified, that
     server will be fetched from the keytab and used unconditionally.  If server is NULL, the keytab will be
     search for a matching principal.

     The keytab argument specifies what keytab to search for receiving principals.  The arguments ap_req_options
     and ticket returns the content.

     When the AS-REQ is a user to user request, neither of keytab or principal are used, instead krb5_rd_req()
     expects the session key to be set in auth_context.

     The krb5_verify_ap_req and krb5_build_ap_req both constructs and verify the AP_REQ message, should not be
     used by external code.

SEE ALSO

     krb5(3), krb5.conf(5)