Abstract: A system for data processing a security critical activity in a secure management mode in a computer, which comprises a processor (10), handling devices (20, 28-38), memory storage resources (14, 42). The system comprises a security device (50) comprising a processor (52) and signal generators (SGPM, SGA), a number of control switches (60), with signal receivers (SRA, SRPM) arranged respectively between the security device and the pre-selected resources.

Abstract: The present invention relates to a method for executing a security critical activity in a security device (40), wherein the security critical activity is executed with user involvement. Each security critical activity is divided into a number of situations/actions, belonging either to a proxy letter group or a user involvement group. The processor (42) of the security device (40) starts the execution of an action of a security critical activity, and then checks if this situation/action can be handled by a proxy letter or shall be handled by a user. If the user or the proxy letter grants the situation/action the execution of the action is continued and ended. This is repeated until all actions of the security critical activity have been executed. If neither the user nor the proxy letter grants the situation/action the execution of the security critical activity will be stopped.

Abstract: A method, a security system and a security device for data processing a security critical activity in a secure management mode, the processing method includes the steps of allocating the security device in response to a call from the processor or the input/output devices, when in a normal mode, transferring the control of the data processing to the security device and thereby entering the secure management mode, processing, with user involvement, the security critical activity on the security device, transferring the result of the data processing of the security critical activity to the processor, the input/output devices or within the security device, and transferring the control of the input/output devices and the control of the data processing from the security device to the processor and thereby again entering the normal mode.