The potential synergies between consumer handheld devices, particularly smartphones and biometric technologies is outlines. The practicalities and challenges for three such technologies - fingerprint, iris and palmprint - are presented. The use of biometrics for personal authentication is discussed, including the use of zero knowledge proof techniques to ensure that the biometric data does not leave the phone. The scope for data theft and breach through spoofing of the original biometric are discussed. Finally the potential impact of this technology synergy on personal privacy is considered.