Design And Implementation Research Of Cryptographic Embedded Microprocessor

In the cryptographic system chip, embedded microprocessor itself doesn't possess cryptographic and secure function. Generally, it achieves relevant accelerator engines through attaching hardware coprocessors on external bus. For the speed of data transmission on external bus is quite lower than on internal bus of microprocessor, the communication cost of data transmission would greatly play down cryptographic service efficiency. A design scheme of cryptographic embedded microprocessor based on ARMv4T architecture is proposed, through extending application specific instruction set to enhance the cryptographic and secure function of embedded microprocessor. It could provide individual cryptographic service for users from bottom, greatly improving cryptographic service efficiency.The main contributions of this paper are given below:1. Referring to ARM9 microprocessor model, an embedded microprocessor based on 32-bit ARM instruction set is designed and realized, providing the extended basic platform for cryptographic embedded microprocessor design.2. Aiming at the special application environment of embedded microprocessor, a new scheme of branch prediction is proposed. Research shows, this scheme owns little resource spending, high prediction efficiency and low cost of invalid prediction.3. Aiming at the multiplier based on Radix-4 Booth encoding, a method entirely eliminating additive operation on partial product generating is advanced, which effectively decreases crucial path delay and chip area consumption.4. Aiming at the two performance targets of speed and area, a structure of multi-cycle multiplier based on adjustable execution cycle is proposed, which not only keeps the performance advantages of multi-cycle multiplier, but also decreases average execution cycles.5. Through the control method of special function registers, a scheme of secure storage is designed, providing an effective mechanism for memory protection of important data. The starting address, area size and accessing permission could be configured by software program.6. Through the control method of extending cryptographic application specific instruction set, a scheme of cryptographic function extension is designed, providing accelerator engines for data encryption and decryption of special cryptographic algorithm.