  Personal authentication is an important process we encounter almost every
day; when we are logging on a computer, entering a company where we work, or a
restricted area, when we are using our plastic credit cards to pay for a
service or to complete some other financial transaction, etc. In each of these
processes of personal authentication some kind of magnetic or optical token is
required. But by using novel technologies like mobile computing and wireless
networking, it is possible to avoid carrying multitude of ID cards or
remembering a number of PIN codes. Article shows how to efficiently
authenticate users via Personal Area Networks (PAN) like Bluetooth or IrDA
using commonplace AES (Rijndel) or MD5 encryption. This method can be
implemented on many types of mobile devices like Pocket PC PDA with Windows CE
(Windows Mobile 2003) real-time operating system, or any other customized OS,
so we will explain all components and key features of such basic system.
