Patent ID: 7568055

Claim:
A data processing apparatus comprising: a storing unit for storing data; an input-output unit for inputting and outputting data to and from the storing unit; and a processing unit for processing data outputted from the storing unit by the input-output unit, wherein the input-output unit inputs and outputs data to and from the storing unit using any one of a first data transfer method , which is a DMA method, and a second data transfer method, which is a PIO method, and the input-output unit comprises: a judging unit for judging which of the first data transfer method and the second data transfer method is to be used according to whether or not a sort of data is image data such that the input-output unit inputs and outputs data to and from the storage unit using the second transfer method, which is the PIO method, when the judging unit judges that the sort of data is data other than image data, including a processing instruction of image data or a control instruction of the storing unit, an encryption unit for encrypting data to be inputted to the storing unit using the first data transfer method, which is a DMA method, when the judging unit judges that the sort of data is image data; and a decryption unit for decrypting data to be outputted from the storing unit using the first data transfer method, which is a DMA method, when the judging unit judges that the sort of data is image data.