针对IDEA算法实现方式的时间攻击

Timing Attack on Implementations of IDEA

传统上认为,密码系统的安全性主要依赖于系统使用的密码算法的安全性,对系统的攻击是基于敌手只能通过系统的输入输出信道获取信息的假设。实际上,密码系统的旁路信息(如时间信息等)也可以被利用来实现攻击。时间攻击就是这一类攻击方法,它通过分析密码系统的运算环节在执行加密过程中的时间信息来恢复密钥。针对IDEA密码算法的实现特点提出一种时间攻击方法,从理论上分析该方法的有效性,并给出抵抗这种攻击的对策。

It is generally believed that the security of cryptosystem mainly relies on the security of cryptographic algorithm used by the system. Attacks on cryptosystem are under the hypothesis that the adversary could only obtain information from I/O channel. However, in practice, the side-channel information（such as execution time etc.） could also be used to achieve attacks. Timing attack belongs to this kind. Timing Attack, through analyzing the information of execution time in the operations of cryptosystem, tries to recover the secret key. This paper proposes a timing-attack method against the implementations of IDEA and theoretically verifies the efficiency of the proposed method. Finally, it provides some countermeasures in resistance of such attack.