This paper studies how to implement a privacy friendly form of ticketing for public transport in practice. The protocols described are inspired by current (privacy invasive) public transport ticketing systems used around the world. The first protocol emulates paper based tickets. The second protocol implements a pay-as-you-go approach, with fares determined when users check-in and check-out. Both protocols assume the use of a smart phone as the main user device to store tickets or travel credit. We see this research as a step towards investigating how to design commonly used infrastructure in a privacy friendly manner in practice, paying particular attention to how to deal with failures.

中文翻译：

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公共交通的隐私友好型电子客票

本文研究如何在实践中实现公共交通票务的隐私友好形式。所描述的协议的灵感来自世界各地当前使用的（侵入性隐私）公共交通票务系统。第一个协议模拟纸质票据。第二种协议实现了一种现收现付的方式，其票价在用户签入和签出时确定。两种协议都假定使用智能电话作为主要用户设备来存储票证或旅行积分。我们认为这项研究是朝着实践中调查如何设计一种常用的基础设施迈出的一步，尤其要注意如何处理故障。