NAME

       pam_otpw - verify one-time passwords

SYNOPSIS

       pam_otpw [ arguments ]

DESCRIPTION

       OTPW  is a one-time password authentication system. It compares entered passwords with hash values stored
       in the user's home directory in the file ~/.otpw.  Once a password was entered correctly, its hash  value
       in ~/.otpw will be overwritten with hyphens, which disables its use in future authentication. A lock file
       ~/.otpw.lock  prevents  that  the  same password challenge is issued on several concurrent authentication
       sessions. This helps to prevent an eavesdropper from  copying  a  one-time  password  as  it  is  entered
       instantly  into a second session, in the hope to get access by sending the final newline character faster
       than the user could.

       Both an authentication management and a session management function  are  offered  by  this  module.  The
       authentication  function  asks for and verifies one-time passwords. The session function prints a message
       after login that reminds the user of the remaining number of one-time passwords.

ARGUMENTS

       debug  Turn on debugging via syslog(3).

       nolock Disable locking. This option tells the  authentication  function  of  pam_otpw.so  to  ignore  any
              existing  ~/.otpw.lock lock file and not to generate any. With this option, pam_otpw.so will never
              ask for several passwords simultaneously.

AUTHOR

       The OTPW package, which includes the otpw-gen progam, has been developed by Markus Kuhn. The most  recent
       version is available from <http://www.cl.cam.ac.uk/~mgk25/otpw.html>.

SEE ALSO

       otpw-gen(1), pam(8)

                                                   2003-09-30                                         PAMOTPW(8)