Patent ID: 8250631

Claim:
An information processing system comprising: a challenge server operatively coupled with a client system, said challenge server comprising an interface for communicating with said client system, wherein said challenge server is configured for: presenting a cryptographic challenge to the client system; initializing a trust cookie that encodes the client system's initial priority level after the client system correctly solves the cryptographic challenge; computing a trust level score for the client system based on a service request, wherein said trust level score is associated with an amount of resources expended by an application server in handling the service request such that a higher trust level score is computed for service requests consuming less system resources; assigning the trust level score to the client system based on the computation; embedding the assigned trust level score in the trust cookie included in all responses sent from the application server to the client system; and the information processing system further comprising: the application server comprising an interface with the client system requesting a service from said application server; a firewall coupled with the application server, said firewall configured to: receive the service request from the client system; receive the trust cookie from the client system; serve the client system by presenting the valid trust cookie at a priority level associated with an assigned trust level score; for the client with a low assigned trust level score, limiting a number of service requests that said client system can issue per unit of time; and dropping any request from a client system with no trust cookie or an invalid trust cookie.