FPGA Implementation of Short Message Authentication Based on the SM4 Algorithm

This paper presents a FPGA implementation of SM4 Encryption and Decryption which has been used in the short message service (SMS) to solve the security risks of information leakage and illegal tampering in the short message service by converting the plaintext into ciphertext for transmission within short message communication system. This paper expands the key bit width based on the traditional SM4 so that the algorithm supports 256-bit keys. The extension of Key Size significantly complicates cryptanalysis efforts, making it exceedingly difficult for analysts to deduce algorithm characteristics from ciphertext, thereby substantially enhancing the security of the algorithm, but throughput (blocks processed per second) is unaffected. Additionally, this paper also introduces enhancements to the operational mode of the encryption algorithm, allowing the authentication module to encrypt and decrypt data of any length. This paper implements an authentication module based on FPGA for encryption and decryption, providing effective security for the transmission of short message data.