Usability and Security

computer and network assets. The relatively small size and low cost allow them to be easilyincorporated into devices and are fairly reliable;• Retina: scanning involves examining the unique patterns on the back of a person’s eye. The retina isthe part of the eye that translates light into the electrical impulses sent to the brain. Because of thecomplexity of current scanners, most retina biometric devices require a relatively large footprint.Most are still used to protect fixed physical assets. Using a retina scanner is also less convenientbecause the user must position himself a certain distance away from the scanner and then rest his orher head on a support or look into a hood. This is necessary in order to effectively read the back ofthe eye;• Iris: Iris scanning is similar to retina, but the scanner is looking at the unique patterns on a person’sIris. This is the “colored” part of the eye and is visible. A key benefit for Iris over Retina is that Irisscanners do not need to be nearly as close to the eye and do not need the eye to be as preciselypositioned;• Face: recognition involves scanning the unique features of a person’s face. Because some aspectschange over time, this is a less reliable form factor. Face recognition is less attractive for up-closeverification than for long distance identification. Once a person is close enough to a physical assetin order to get a high quality biometric scan, other form factors are viable and are currently muchmore reliable.Wilson also outlines the usability (effort) and the security value for the different types of biometric formfactors 40 :Figure 3: Usability (effort) and security values3.3.4.1 Recapitulation & analysisUsability aspects:• Effectiveness: the users’ goal with effectiveness is to get access to a system or building as accurateand complete as possible. Facial recognition is still not mature enough and handprints change overtime (e.g. juvenile finger growth). Perhaps for other form factors more effort is needed, but in thiscase we consider all types with the exception of the facial and handprint type;• Efficiency: the users’ goal with efficiency is to get access to a system or building as accurate andcomplete as possible, using minimal resources (e.g. time). Based on the discussions above we can21