The book critically analyzes the current state of security procedures in online banking. In addition to various PIN/TAN methods and HBCI, it also considers other systems such as PayPal in its outlook. Security is regarded as the top priority in online banking. However, an analysis of the available security methods shows that security is not an absolute priority; rather, banks and users make their decisions within a balancing act of security, costs, and user-friendliness. Almost 20 years ago, the associations of the German banking industry decided to introduce signature methods in online banking with the HBCI standard to replace the PIN/TAN method, which was then considered to be of low security. However, the PIN/TAN methods were further developed, and HBCI could not establish itself. This book presents its findings based on expert interviews.