Integrated Circuit Security

An integrated circuit having a security supervision system with a plurality of functional circuit blocks mutually interconnected so as to be capable of collectively performing data processing tasks. One or more communication adaptors to the functional circuit blocks are capable of sensing the state and/or activity of the functional circuit block. A memory stores definitions of state and/or activity of the functional circuit block and actions corresponding to each definition. In security mode the communication adaptors monitor traffic characteristics between the cores, and the state of the cores, for a match to a stored related trigger. The state and/or activity of the said functional block is compared with each definition and when state and/or activity of the said functional block correspond to a stored definition the corresponding action is performed. The action is one of at least partially disabling the functional circuit block and causing a message to be transmitted to a destination off the integrated circuit. The processing circuitry of the communication adaptors is implement in hardware that operates in a separate clock domain to the functional circuit block to which it is connected.