Patent ID: 7913307

Claim:
An information processing apparatus for input data, comprising, in combination: a semiconductor integrated circuit comprising a central processing unit CPU controlling read, write and encryption operations on said input data, an external memory interface circuit and an external memory disposed outside the semiconductor integrated circuit and responsive to control signals from said central processing unit CPU through said external memory interface circuit and said external memory; wherein said semiconductor integrated circuit further includes, an encryption circuit responsive to said central processing unit CPU generating encrypted data by encrypting the input data to be stored in the external memory; write means responsive to said central processing unit CPU for writing the encrypted data into the external memory; readout means responsive to said central processing unit CPU for reading out the encrypted data from the external memory; and a decryption circuit decrypting the readout encrypted data from the external memory, said central processing unit CPU providing address (ADR), data write command WR, read (RD), wait, and data signals to said external memory interface, said external memory interface providing external address (EADR), external read (ERD), external data signals (EDATA), and an address decoder receiving said input address information from said central processing unit and providing as an output a chip select signal (ECS) to said external memory, said chip select signal ECS providing address information indicating a storage location of the input data to be stored as encrypted data at said storage location in said external memory, wherein the encryption circuit generates the encrypted data by performing encryption of the input data for the storage location of the encrypted data to be stored in the external memory, and the decryption circuit decrypts the readout encrypted data in accordance with the storage location of the encrypted data, so that if the encrypted data are copied from the external memory, it is difficult to decrypt the encrypted data without knowing the storage location of the encrypted data in the external memory.