Digipass Plug-In for IAS Product Guide - Vasco

Digipass Plug-In for IAS Product Guide Digipass
2.2.4 Digipass Record Settings
These settings are kept in the record for a Digipass Application, and affect which OTP is
expected by the IAS Plug-In.
2.2.4.1 Time/Event-based Settings
Time Based
Specifies whether the algorithm for the Digipass application is time-based (see Time/Eventbased
Digipass Applications for more information).
Time Step Used
The time step used by the Digipass Application (see Time/Event-based Digipass
Applications for more information).
Last Time Shift
Time Shift records any misalignments between the time recorded on the Digipass and the time
recorded on the server, each time a User logs in. This ensures that if either clock drifts from
the correct time, an allowance can be made by the IAS Plug-In and the User will still be able to
log in. If the time drift goes beyond the allowable time window between User logins, the
Digipass record will have to be reset (this allows for recalculation of the time drift).
Example
Time window may be 5 steps in either direction.
This means that 11 OTPs would be considered valid – the exact OTP for that time,
and the OTPs for the 5 time steps either side of the exact time. If the OTP given is
for a different time step, the time shift for that Digipass will be recorded. The next
time the User logs in, the expected OTP will be calculated based on that time shift.
Last Event Value
The current number of uses of the Digipass Application, according to the Digipass. This can
get out of sync with the number of uses recorded by the IAS Plug-In when:
login failures occur for other reasons than incorrect OTP
the Digipass has been used without a login (eg. children have been playing with it)
The Digipass is being used to log in to two separate systems
The purpose of this setting is much the same as the Last Time Shift setting – it allows the IAS
Plug-In to track any shifts between the event count recorded by itself and the Digipass.
2.2.4.2 Response Length
This setting determines the length of the OTP (excluding check digit) expected by the server
from the Digipass Application.
© 2005 VASCO Data Security Inc. 27