In this paper we propose a novel abstraction that we have named Range-Revocable Pseudonyms (RRPs). RRPs are a new class of pseudonyms whose validity can be revoked for any time-range within its original validity period. The key feature of RRPs is that the information provided to revoke a pseudonym for a given timerange cannot be linked with the information provided when using the pseudonym outside the revoked range. We provide an algorithm to implement RRPs using efficient cryptographic primitives where the space complexity of the pseudonym is constant, regardless of the granularity of the revocation range, and the space complexity of the revocation information only grows logarithmically with the granularity; this makes the use of RRPs far more efficient than the use of many short-lived pseudonyms. We have used RRPs to design EDGAR, an access control system for VANET scenarios that offers backward unlinkability. The experimental evaluation of EDGAR shows that, when using RRPs, the revocation can be performed efficiently (even when using time slots as small as 1 second) and that users can authenticate with low latency ($0.5-3.5$ ms).

翻译：本文提出了一种名为范围可撤销假名（RRPs）的新型抽象概念。RRPs是一类新型假名，其有效性可在原始有效期内针对任意时间范围被撤销。RRPs的关键特性在于：用于撤销特定时间范围内假名的信息，与在该撤销范围外使用假名时提供的信息无法关联。我们提出了一种利用高效密码学原语实现RRPs的算法，其中假名的空间复杂度保持恒定，与撤销范围的粒度无关，而撤销信息的空间复杂度仅随粒度对数增长；这使得RRPs的使用比使用大量短生命周期假名更为高效。我们利用RRPs设计了EDGAR——一个面向车联网场景的后向不可链接访问控制系统。EDGAR的实验评估表明：使用RRPs时，撤销操作可高效执行（即使时间片小至1秒），且用户能够以低延迟（0.5-3.5毫秒）完成认证。