Method and security system for processing a security critical activity

A security system for data processing a security critical activity, the security critical activity being part of an application running on the security system, comprising:

• a processor (14),
• input/output devices (4, 6, 8, 12),
• a security device (40),
• means (28, 30, 32, 34) for transferring the control of the data processing of the application and the control of the input/output devices (4, 6, 8, 12) from the processor (14) to the security device (40), and thereby entering a secure management mode, in which mode the processor (14) is incapable of accessing any of the requested input/output devices (4, 6, 8, 12),
• means (42, 44) for processing, with user involvement, the security critical activity on the security device (40), the user involvement comprising an act-of-will of the user by means of a user input to the security device proving user presence while the secure management mode prevails,
• means (42) for transferring the result of the data processing of the security critical activity to the processor (14), the input/output devices (4, 6, 8, 12) or within the security device (40), and
• means (28, 30, 32, 34) for transferring the control of the input/output devices (4, 6, 8, 12) and the control of the data processing from the security device to the processor (14).

Method for data processing a security critical activity in a secure management mode, the security critical activity being part of an application running on a system comprising a processor (14), input/output devices (4, 6, 8, 12) and a security device (40), said processing method comprising the following steps:

• allocating the security device (40) in response to a call from the processor (14) or any of the input/output devices (4, 6, 8, 12), when in a normal mode,
• transferring the control of the data processing of the application and the control of requested input/output devices (4, 6, 8, 12) from the processor (14) to the security device (40) and thereby entering the secure management mode, in which mode the processor (14) is incapable of accessing any of the requested input/output devices (4, 6, 8, 12),
• processing, with user involvement, the security critical activity on the security device (40),
• transferring the result of the data processing of the security critical activity to the processor (14), the input/output devices (4, 6, 8, 12) or within the security device (40), and
• transferring the control of the input/output devices (4, 6, 8, 12) and the control of the data processing from the security device (40) to the processor (14) and thereby entering the normal mode,
• wherein the step of processing the security critical activity, with user involvement, comprises the steps of:
• requesting generation of an irrevocable step,
• presenting the request together with the arguments of this step,
• giving the user the option to alter the arguments or enter new arguments,
• letting the user accept or refuse the request of generation and if accepted
• continuing the processing including the irrevocable step and if refused
• entering the normal mode.