中文摘要：

为研究高级数据加密标准（AES）针对电磁旁路攻击的脆弱性，分析了微处理器的电磁信息泄漏模型和攻击AES时D函数的选择问题。针对PHILIPS 89C51实现的AES-128密码系统，采用差分电磁分析的方法进行了密码破译实验，成功获得了128住密钥。经分析发现AES的字节替代变换可产生密钥泄露，为密码系统实施相关防护措施提供了依据。

英文摘要：

To study the vulnerability of Advanced Encryption Standard （AES） against electromagnetic side channel attacks, the article analyzed the electromagnetic information leakage model of microcomputer and the choice of D function. Then, concerning the AES-128 bits cryptographic system realized by the 89C51 microchip, Differential Electromagnetic Analysis （DEMA） algorithm, which was used into an attack experiment and succeeded in obtaining 128 bits secret key of AES-128, was described. After analyzing the experimental results, the leakage of secret information produced by ByteSub transformation was detected. This method can be regarded as a new protective measure in cryptographic systems.