One Time Password is a password that is valid for a short period of time (e.g. only one login session or transaction) and is aimed at avoiding a number of shortcomings that are associated with traditional static passwords. One of the most popular approaches for generating OTPs is time-synchronization between the authentication server and the client. OTP implementations are often used in two factor authentication solutions where the user enters a pin which is used as a variable in an algorith that generates evidence of identity which is sent to an enforcement agent that determines if the identity is valid.