Abstract: By analyzing the features of International Data Encryption Algorithm（IDEA）, this paper presents a Differential Power Analysis（DPA） attacking method on IDEA code system, which is based on Hamming distance. The method is one particularly powerful type of Side Channel Attacks（SCA）. All its theories are based upon the physical characters, power consumption models and data dependent power consumption of CMOS logic gates which form the Integrated Circuits（ICs）. The paper introduces the design and realization of DPA attacks of IDEA. Correct secret key of encryption algorithm is cracked successfully with experiments. It comes gradually and closely into ultimate target of the attack. The result indicates that IDEA encrypted system without some extra protective measures can’t resist the attacks of DPA, because of the leakages from the physical signals and the difference of power consumption while processing the different data of ICs. The results can provide the researchers a useful reference for the safety design.

Key words: International Data Encryption Algorithm（IDEA）, differential power analysis attacks, Hamming distance, power consumption model, side channel attacks

摘要： 研究分析国际数据加密算法IDEA的特点，采用差分功耗分析攻击方式进行密钥破解，针对IDEA算法提出一种基于汉明距离的差分功耗攻击方法。该攻击方法是一种典型的加密芯片旁路攻击方式，其理论基础为集成电路中门电路在实现加密算法时的物理特性、功耗模型及数据功耗相关性。详细介绍了针对IDEA加密系统进行差分功耗攻击的设计与实现，开发了相应的仿真实验平台，实验成功破解了IDEA加密算法的密钥，从而给IDEA加密算法研究者提供了有益的安全设计参考。实验表明，未加防护措施的IDEA加密系统难以抵御差分功耗的攻击。

关键词: 国际数据加密算法（IDEA）, 差分功耗攻击, 汉明距离, 功耗模型, 旁路攻击