Out-of-band challenge in a computer system

A computer system for access control for a consumer accessing a restricted resource comprising:

• a processor device and memory storing computer program code for access control for the consumer accessing the restricted resource in the computer system connected to an access network;
• receiving a continuous sequence of data records while the consumer is accessing and using the restricted resource over the access network;
• continuously comparing the received data records with an access control policy for the restricted resource, wherein the access control policy is accessed or received and applied by an out-of-band (OOB) access control system to identify any deviation from the access policy by the consumer using the restricted resource;
• in response to a determination that a behavior of the consumer is non-compliant with respect to the access control policy, generating and communicating a shared secret to the consumer, the shared secret being communicated via an OOB communications channel other than the access network;
• receiving and validating, by the OOB access control system, a response to a challenge corresponding to the shared secret from the consumer via the access network;
• and
• notifying the computer system that access to the restricted resource by the consumer should be precluded based on the validation of the response to the challenge and the shared secret.