Patent ID: 7669052

Claim:
A data processing system operable to transmit encryption data, said data processing system comprising: a first apparatus having a command identifier; and a second apparatus having an encryption processing section for executing encryption processing on data transmitted to and from said first apparatus, said encryption processing section including a control section operable to receive said command identifier in accordance with a pre-defined setting sequence, to retrieve a command from a register, said command corresponding to said command identifier, and to have said command executed, wherein, if said command identifier differs from said predefined setting sequence, said control section is operable to cancel execution of said command, said pre-defined setting sequence is a command number setting sequence in which numbers are sequentially incremented, and said control section is operable to store a value of said command identifier received from said first apparatus in a memory, to compare a new command identifier received from said first apparatus with said pre-defined setting sequence based on said received value stored in said memory and, if said new command identifier is different from said pre-defined setting sequence, to reset said command identifier stored in said memory without performing command processing corresponding to said new command identifier.