User Manual

37
About the Security Level
The security level is an important part of the identification system. A higher security level
reduces the risk of an unauthorised person logging into an account. An administrator can
set the security level for biometric users. The security level is set globally; i.e. the set secu-
rity level affects all biometric users in the domain.
The False Acceptance Rate, FAR, is a parameter used to indicate the probability that an
unauthorised user is given access to an account. The False Rejection Rate, FRR, indicates
the probability that an authorised user is denied access to an account.
A secure system, i.e. a system with a high security level, means a low false acceptance rate.
• Higher security levels = an excellent match between the fingerprint on the sensor
and the fingerprint template in the database is required. The FAR is very low;
the FRR is comparatively high.
• Lower security levels = a less perfect match between the fingerprint on the
sensor and the equivalent fingerprint template in the database is required.
The FAR is comparatively high; the FRR is low.
Higher security levels (level 6 or 7) result in:
• A very secure system. It will be virtually impossible for an unauthorised person to
log into a user account.
• A system which sometimes rejects an authorised user trying to log into an
account. A small scratch, a distorted fingerprint or poor finger positioning on the
fingerprint reader may produce a fingerprint that the system does not accept as
a satisfactory match to the fingerprint template stored in the database.
Lower security levels (level 1or 2) result in:
• A less secure system. At lower security levels, the risk of an unauthorised user
logging into an account increases.
• A system which very rarely rejects an authorised user who wants to log into
an account.
Security level 4 is recommended to guarantee a reliable system that grants easy access
to authorised users while barring unauthorised users.
When should the higher and lower levels be selected? A lower security level is selected
when there is little risk of an unauthorised user attempting to log on, and a very fast verifi-
cation process is desirable. A higher security level is selected when security is the main
concern. In this case, the verification process may take a little longer.
NOTE: An experienced biometric user is less likely to be falsely rejected than a novice
biometric user. The FRR decreases as a user gets more used to biometric logon and learns
a proper finger placement.
Chapter 5 The BioManager for Domains