Arm Limited

Timothy Charles Thornton

Peter William Harris

Peter Brian Wilson

David Paul Martin

A smart card comprising a data store and a processor, said smart card being operable to connect with a host data processing apparatus, said smart card comprising authentication logic operable when connected to said host data processing apparatus to identify a secure data processing domain having predetermined properties within said host data processing apparatus and in response to identify said secure data processing domain, said smart card is operable to delegate at least some data processing operations to be processed within said secure data processing domain of said host data processing apparatus.

Processing efficiency on secure systems having a host processor and smart card

A data processing apparatus and method are provided for managing access to a display buffer. The data processing apparatus has a display buffer for storing an array of display elements for subsequent output to a display controller, with each display element having a security permission indication associated therewith identifying whether that display element is a secure display element or a non-secure display element. At least one processing unit is provided for executing a non-secure process and a secure process, each process issuing access requests when seeking to access display elements in the display buffer, and each access request specifying a location in the display buffer. Interface logic is associated with the display buffer for receiving each access request and is arranged for at least each access request issued by the non-secure process to determine the security permission indication associated with the display element currently stored at the location specified by that access request. Based on the security permission indication, the interface logic then determines how that access request should be processed. Accordingly, the interface logic can selectively prevent access to secure display elements by the non-secure process, so as to protect the security of secure display elements contained within the display buffer.

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Reading, United Kingdom

Timothy Charles Thornton