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.
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>.