Patent ID: 8291472

Claim:
A method for adjusting authentication conditions in real-time, the method comprising: dynamically constructing within a device coupled to a physical system a graph-theoretic data structure, the graph-theoretic data structure having nodes corresponding to received valid and invalid authentication credentials used in attempts to access the system, wherein the dynamically constructing comprises: if a newly received credential has no corresponding node in the data structure, adding in real-time a new node to the data structure corresponding to the newly received credential and, if a last received preceding credential was an invalid credential, adding a directed edge from a last node corresponding to the last received preceding credentials to the new node, and computing in real-time a weight for a directed edge between nodes corresponding to consecutively received credentials; in response to receipt of an invalid credential, computing based on the graph-theoretic data structure a probability of the invalid credential being an authentication attempt by a particular type of user; and if the probability is beyond a threshold probability, triggering a security event to adjust an authentication condition of the system.