Privacy preservation in Ride Hailing Services is intended to protect privacy of drivers and riders. ORide is one of the early RHS proposals published at USENIX Security Symposium 2017. In the ORide protocol, riders and drivers, operating in a zone, encrypt their locations using a Somewhat Homomorphic Encryption scheme (SHE) and forward them to the Service Provider (SP). SP homomorphically computes the squared Euclidean distance between riders and available drivers. Rider receives the encrypted distances and selects the optimal rider after decryption. In order to prevent a triangulation attack, SP randomly permutes the distances before sending them to the rider. In this work, we use propose a passive attack that uses triangulation to determine coordinates of all participating drivers whose permuted distances are available from the points of view of multiple honest-but-curious adversary riders. An attack on ORide was published at SAC 2021. The same paper proposes a countermeasure using noisy Euclidean distances to thwart their attack. We extend our attack to determine locations of drivers when given their permuted and noisy Euclidean distances from multiple points of reference, where the noise perturbation comes from a uniform distribution. We conduct experiments with different number of drivers and for different perturbation values. Our experiments show that we can determine locations of all drivers participating in the ORide protocol. For the perturbed distance version of the ORide protocol, our algorithm reveals locations of about 25% to 50% of participating drivers. Our algorithm runs in time polynomial in number of drivers.

翻译：RHS 在 2017 USENIX 安全 专题讨论会上公布 ORID 早期 RHS 提案之一 。 在 ORID 协议中, 骑手和司机在区域操作, 使用“ 某些单调的单调加密计划” 加密其位置并将其传送到服务供应商(SP) 。 SP 以单调方式计算载客和可用驾驶员之间的平方欧立德距离。 Rider 接收加密距离, 并在解密后选择最佳搭乘者 。 为了防止三角攻击, SP 随机调整司机的距离, 然后再将他们送到骑手手中。 在这项工作中, 我们建议采用被动攻击, 使用三角定位来确定所有参与司机的坐标, 这些司机的距离可以从多个诚实但有色调的搭接者的角度出发。 SAC 2021 发布了对 ORide 袭击 。 同一文件提议使用热调 Euclide 距离以挫败击他们的攻击。 我们把攻击扩大到了50 级司机的距离位置, 我们使用多调的驱动员的频率 。