Patent ID: 8621586

Claim:
A method of processing an authentication request from an authentication requestor, the authentication request including a user identifier and current user data, the method comprising: receiving the authentication request at an adaptive authentication system which includes a database having a set of entries, each entry of the set of entries including an identifier and previous user data, the adaptive authentication system being constructed and arranged to perform an adaptive authentication operation on the authentication request, the adaptive authentication operation being constructed and arranged to generate an adaptive authentication result which indicates a likelihood of the authentication request being associated with fraudulent activity; performing the adaptive authentication operation on the authentication request, including: matching the user identifier of the authentication request with an identifier of a particular entry of the database; performing a comparison of the current user data of the authentication request with the previous user data of the particular entry, the comparison producing a comparison result; and generating an adaptive authentication result based on the comparison result; and sending the adaptive authentication result to the authentication requestor; wherein the current user data includes a fact identifier and a current fact value which is associated with the fact identifier; wherein the previous data of the particular entry includes a set of previous fact values, each previous fact value being associated with the fact identifier and including a fact value count; and wherein performing the adaptive authentication operation on the authentication request further includes: if the current fact value is equal to a previous fact value of the set of previous fact values: incrementing the fact value count of the previous fact value to which the current fact value is equal; and if the current fact value is not equal to a previous fact value of the set of previous fact values: locating a minimal previous fact value of the set of previous fact values, the minimal previous fact value having the smallest fact value count of the fact value counts of the previous fact values of the set of previous fact values; decrementing the fact value count of the minimal previous fact value; if the fact value count of the minimal previous fact value is less than or equal to zero: removing the minimal previous fact value from the set of previous fact values; and adding the current fact value to the set of previous fact values; and if the fact value count of the minimal previous fact value is greater than zero: retaining the minimal previous fact value in the set of previous fact values.