Sentinel Hardware Keys Developer's Guide - Customer Connection ...

Chapter 7 – Implementing Secure Licensing
Contents Glossary Index Troubleshooting
independent of the system clock—providing the best solution against time
tampering attacks.
Non-RTC tokens with Sentinel V-Clock also allow reliable and secure distribution
of time-limited applications. These do not require an on-board
battery to detect time tampering and allow you to tolerate the number of
time tampering attempts specified in the cheat counter.
Cheat Counter Behavior
170 Sentinel Hardware Keys Developer’s Guide
Cheat counter is a count-down value that allows tolerating the time tampering
attacks ranging between 1 second to 30 days (excluding the daylight
savings) till it reaches zero. Its behavior is described as follows:
Cheat Counter Behavior
Scenario Outcome Corrective Measures
When the system clock is
tampered for a duration
between 1 second to 30
days (excluding the
daylight savings)
When the system clock is
tampered more than once
(between 1 second to 30
days) during
one power-up session of
the Sentinel Key a
The system clock is
tampered for more than 30
days
Cheat counter
decrements by one.
The AES/ECC algorithms
are disabled—regardless
of the cheat counter
value.
This prevents against
multiple time tampering
attempts during one
power-up session.
The AES/ECC algorithms
are disabled—regardless
of the cheat counter
value.
The application will run successfully till
cheat counter has reached zero. After
which, the AES/ECC algorithms are
disabled and the associated API
functions return error. You can decide
the behavior of the application under
such circumstances.
If the Sentinel Key is re-plugged,
normal functionality can be
resumed.
If the system clock is corrected, normal
functionality can be resumed.
If the system clock is corrected, normal
functionality can be resumed.
a. Refers to the duration between the plug-in and plug-out of the Sentinel Key.