Abstract: A method for facilitating the detection of misuse of an identity during an electronic transaction comprises the step of receiving a notification to authenticate the use of an identity at a first location, wherein the identity is associated with a mobile phone; determining an approximate location of the mobile phone, and determining whether the first location and mobile phone locations match in geographical proximity. The approximate location of the mobile phone is determined based on cached position information. The invention provides a method for ensuring that the cached position information is up to date, by overwriting stale information with new position information derived by accessing a database that correlates Wi-Fi signals detected by the mobile phone with a geographic location.