Humanitarian aid-distribution programs help bring physical goods (e.g., food, blankets) to people in need. Traditional paper-based solutions to support aid distribution do not scale to large populations and are hard to secure. Existing digital solutions solve these issues, at the cost of collecting large amount of personal information. Failing to protect aid recipients' privacy can result on harms for them and enables surveillance in the long run. In collaboration with the International Committee of the Red Cross, we build a safe aid-distribution system in this paper. We first systematize the requirements such a system should satisfy and then propose a decentralized solution based on the use of tokens. Our design provides strong scalability and accountability, at the same time, ensures privacy by design. We provide two instantiations of our design, on a smart card and on a smartphone. We formally prove the security and privacy properties of our design, and empirically show that the two instantiations can scale to hundreds of thousands of recipients.

翻译：人道主义援助分发项目旨在为有需要的人群提供实物（如食品、毯子）。传统的纸质援助分发方案难以规模化应用于大规模人群，且难以保障安全性。现有的数字解决方案虽能解决这些问题，但代价是收集大量个人信息。未能保护受助者的隐私可能导致其遭受伤害，并长期助长监控行为。本文与国际红十字会合作，构建了一个安全的援助分发系统。我们首先系统化梳理了此类系统应满足的需求，随后提出一种基于令牌的去中心化解决方案。我们的设计在提供强可扩展性与可问责性的同时，通过设计确保了隐私保护。我们提供了该设计的两种实例化方案——分别基于智能卡与智能手机实现。通过形式化方法证明了设计的安全与隐私属性，并实证表明两种实例化方案均可扩展至数十万受助者的规模。