Current technology is evolving fast and is constantly bringing new dimensions to our daily life. Electronic banking systems provide us with easy access to banking services. The interaction between user and bank has been substantially improved by deploying ATMs, phone banking, Internet banking, and more recently, mobile banking. This paper discusses the security of today’s electronic banking systems. We focus on Internet and mobile banking and present an overview and evaluation of the techniques that are used in the current systems. The best practice is indicated, together with improvements for the future. The issues discussed in this paper are generally applicable in other electronic services such as E-commerce and E-government.