Patent ID: 8549325

Claim:
A method of impeding leakage of cache access behavioural information of a section of a sensitive process to an untrusted process, said sensitive and untrusted processes being performed by a processor within a data processing apparatus, said data processing apparatus further comprising at least one cache operable to store information required by said processor while performing said sensitive and untrusted processes, the method comprising: prior to commencing processing of a section of said sensitive process by said processor, evicting information stored in locations of said at least one cache which at least some of which would otherwise be evicted by said sensitive process loading further information at least some of which is required by said section of said sensitive process in said at least one cache, said evicting said information comprising storing said further information at least some of which is required by said section of said sensitive process in said at least one cache; commencing processing of said section of said sensitive process by said processor; switching said processor during processing of said section of said sensitive process to said untrusted process in response to a switching request; on switching back to said section of said sensitive process from said untrusted process, evicting information stored in locations of said at least one cache at least some of which would otherwise be evicted by said sensitive process loading information at least some of which is required by said section of said sensitive process in said at least one cache prior to recommencing processing of said section of said sensitive process.