USB Keyboard Security Unit

24 Published By: Blue Eyes Intelligence Engineering & Sciences Publication Pvt. Ltd. Abstract— Every user has its specific rhythm of typing which could be used as a biometrics in order to build some kind of "footprint" – unique profile. If somebody gets to know this profile, legitimate user is endangered by tracking and being impersonated. That is the way typing rhythm must be protected. We designed a hardware-based device in order to protect the identity of the individual during usage of keyboard (typing). The unit is plugged between the keyboard and the personal computer and works as an interface modifying data on the fly in the model "man in the middle". Thanks to these modifications, an adversary who eavesdrops communication between a legitimate user and workstation gets practically no information about the "keystroking identity" of user. The security unit is based on two microprocessors: AVR AT90USB1287 working as USB Host simulating workstation and AVR Atmega88 working as USB Device simulating virtual keyboard. In the paper we present technical details of the security unit including electronic schemes and PCB referring to previously designed protection algorithms and results of performed efficiency tests as well.