Abstract: To improve the efficiency of Advanced Encryption Standard （AES） algorithm on ARM processor, aiming at AES algorithm with 128-bit block length and key length, an optimization method was proposed. The method can speed up execution efficiently on ARM processor while consuming less ROM memory. A theoretical analysis of the Rijndael algorithm and of the proposed optimization was discussed. S box was generated by real-time calculation. The MixColumns and InvMixColumns transformations were amended to execute efficiently on 32-bit processor. On-the-fly key expansion was adapted. Simulation results of the optimized algorithm on S3C2440 processor were presented. The experimental results show that the optimization of AES algorithm can execute efficiently on S3C2440 and consume less ROM memory. The method can be applied to embedded systems with memory constraints.

Key words: Advanced Encryption Standard (AES), encryption, key expansion, ARM, algorithm optimization

摘要： 为了提高高级加密标准（AES）算法在ARM上的执行效率，针对明文长度和密钥长度均为128位的AES算法，提出了一种在ARM上高效运行并且占用较少ROM空间的实现方案。S盒采用即时计算的方法生成，将列混合和逆列混合修改为针对32位字的操作，密钥扩展采用即时密钥扩展。在S3C2440处理器上实现的实验结果表明,AES算法的优化方案可以在ARM处理器上高效运行并占用了较少的ROM空间。该方案可以应用于存储空间较小的嵌入式系统中。

关键词: 高级加密标准, 加密, 密钥扩展, ARM, 算法优化