Abstract: With the city rail networks become more and more complex and intelligent, its automatic fare collection (AFC) system also becomes more and more complicated. Hence security protection mechanism for the AFC becomes necessary. An AFC system for city rail systems is designed in this paper. By using the cryptographic techniques, the designed AFC system is shown to be secure against impersonation attack, forgery attack, and cloning attack. The designed AFC system is also shown to have good extensibility, because the computational complexity in verifying the validity of the tickets and their balances does not depend on the number of the whole tickets.

Key words: City rail, Automatic fare collection, Radio frequency identification, Information security, Hash function

摘要： 随着城市轨道交通网络的复杂化和智能化，城市轨道交通的自动售检票系统（AFC）也变得越来越复杂，因此自动售检票系统（AFC）的信息安全保护机制是必不可少的。我们设计了一种城市轨道交通安全自动售检票系统，通过使用密码学技术，分析了该安全自动售检票系统在对抗假冒攻击、伪造攻击和克隆攻击等方面的能力。我们提出的方案还具有很好的可扩展性，其对票卡及其余额验证的计算复杂度不因票卡数量的增加而增加。

关键词: 城市轨道交通, 自动售检票系统, RFID, 信息安全, 杂凑函数