1. A method of executing independent trusted applications in a processor having a plurality of trusted security zones, comprising: invoking a first trusted application to execute in a first subordinate trusted security zone of the processor, wherein the first trusted application is invoked by a master trusted application executing in a master trusted security zone of the processor and wherein the master trusted application has no visibility into a first memory space associated with the first subordinate trusted security zone and no visibility into the processing of the first trusted application; and invoking a second trusted application to execute in a second subordinate trusted security zone of the processor, wherein the second trusted application is invoked by the master trusted application executing in the master trusted security zone of the processor and wherein the master trusted application has no visibility into a second memory space associated with the second subordinate trusted security zone and no visibility into the processing of the second trusted application, wherein the master trusted security application mediates access to the first trusted security zone and to the second trusted security zone.