PAMOTPW(8)						      System Manager's Manual							PAMOTPW(8)

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 authenti-
       cation 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)