Biometrics on Mobile Phone

In an era of information technology, mobile phones are more and more widely used worldwide, not only for basic communications, but also as a tool to deal with personal affairs and process information acquired anywhere at any time. It is reported that there are more than 4 billion cell phone users over the world and this number still continues to grow as predicted that by 2015 more than 86% of the world population will own at least one cell phone (Tseng et al., 2010). The massive volume of wireless phone communication greatly reduces the cost of cell phones despite their increasingly sophisticated capabilities. The wireless communication capability of a cell phone has been increasingly exploited for access to remote services such as e-commerce and online bank transaction. Smart phones are providing powerful functionality, working as a miniaturized desktop computer or Personal Digital Assistant (PDA). More excitingly, most of the state-of-the-art mobile phones are now being incorporated with advanced digital imaging and sensing platforms including various sensors such as GPS sensors, voice sensors (microphones), optical/electrical/magnetic sensors, temperature sensors and acceleration sensors, which could be utilized towards medical diagnostics such as heart monitoring, temperature measurement, EEG/ECG detection, hearing and vision tests to improve health care (Wang & Liu, 2009) especially in developing countries with limited medical facilities. These scenarios, however, require extremely high security level for personal information and privacy protection through individual identification against un-authorized use in case of theft or fraudulent use in a networked society. Currently, the most adopted method is the verification of Personal Identification Number (PIN), which is problematic and might not be secured enough to meet this requirement. As is illustrated in a survey (Clarke & Furnell, 2005), many mobile phone users consider the PIN to be inconvenient as a password that is complicated enough and easily forgotten and very few users change their PIN regularly for higher security as can been seen from Fig. 1. As a result, it is preferred to apply biometrics for the security of mobile phones and improve reliability of wireless services. As biometrics aims to recognize a person using unique features of human physiological or behavioral characteristics such as fingerprints, voice, face, iris, gait and signature, this authentication method naturally provides a very high level of security. Conventionally, biometrics works with specialized devices, for example, infrared camera for acquisition of