LOGIN_SKEY(8)           OpenBSD System Manager's Manual          LOGIN_SKEY(8)

NAME
     login_skey - provide S/Key authentication type

SYNOPSIS
     login_skey [-s service] [-v fd=number] user [class]

DESCRIPTION
     The login_skey utility is called by login(1), su(1), ftpd(8), and others
     to authenticate the user with S/Key authentication.

     The service argument specifies which protocol to use with the invoking
     program.  The allowed protocols are login, challenge, and response.  The
     default protocol is login.

     The fd argument is used to specify the number of an open, locked file de-
     scriptor that references the user's S/Key entry.  This is used to prevent
     simultaneous S/Key authorization attempts from using the same challenge.

     The user argument is the login name of the user to be authenticated.

     The optional class argument is accepted for consistency with the other
     login scripts but is not used.

     login_skey will look up user in the S/Key database and, depending on the
     desired protocol, will do one of three things:

     login      Present user with an S/Key challenge, accept a response and
                report back to the invoking program whether or not the authen-
                tication was successful.

     challenge  Return the current S/Key challenge for user.

     response   Report back to the invoking program whether or not the speci-
                fied response matches the current S/Key challenge for user.

     If user does not have an entry in the S/Key database, a fake challenge
     will be generated by the S/Key library.

FILES
     /etc/skey  directory containing user entries for S/Key

SEE ALSO
     login(1), skey(1), skeyinfo(1), skeyinit(1), login.conf(5), ftpd(8)

OpenBSD 4.7                      May 31, 2007                                1
