The invention relates to an off-
chip Nor Flash
bus interface hardware
encryption device which comprises an EMI (
external memory interface), a data reading decryption passage, a data reading bypass passage, a data writing passage and an AES (
advanced encryption standard)
encryption engine, wherein the EMI is used for CPU (
central processing unit) extensible external memories, the three passages connects the EMI with external Nor Flash memories, the AES
encryption engine is connected between a CPU and the data reading decryption passage and used for
plaintext data encryption, and the data reading decryption passage comprises an address analyzing unit, an address comparing unit, an indication
control unit, a
cipher text buffer unit, an AES decryption engine, a
plaintext buffer unit and a secret
key storage unit. Hardware-
software combination is used to provide data encryption for off-
chip Nor Flash memories. The device supports a bypass function, data can be written into off-
chip Nor Flash memories in
plaintext and read in plaintext, so that data storage flexibility is achieved. By the device which is flexible in
extensibility, easy to design, high in reliability and safety and the like, Nor Flash
bus interface encryption is achieved.