Location-based service (LBS) in vehicular ad hoc networks (VANETs) has significantly benefited information acquisition from geographically-based social networking. Authentication guarantees the unforgeability and the effectiveness of the LBS information. Unfortunately, owing to a large quantity of redundant or useless LBS messages disseminated in VANETs, the heavy authentication overhead of the existing work adopting a periodically released authentication key, filtering with message identifiers or exploiting public key (fully) homomorphic encryption (FHE), is either intolerable by resource-constrained on-board units (OBUs) or inappropriate to the realtime controlling requirement for VANETs. In this paper, an efficient multi-key secure outsourced computation scheme MSOC without exploiting public key FHE is first proposed, in the setting of two non-colluding servers, namely the cloud and the cryptographic service provider (CSP). Then, based on MSOC, an efficient and secure comparison protocol LSCP is devised, without the interaction between the server and the users. Furthermore, a lightweight privacy-preserving authentication protocol LPPA for LBS in VANETs is proposed, by eliminating duplicate and useless encrypted LBS messages before authentication is executed, through a newly devised efficient privacy-preserving information filtering system. Both user’s location privacy and interest privacy are well protected against even the collusion between the roadside units (RSUs) serving as the cloud (or CSP) and malicious users. Especially, the property of ciphertext re-encryption of our proposed MSOC also guarantees the interest pattern privacy whether two users accept the same LBS information. Finally, formal security proof and extensive simulation results verify the effectiveness and practicability of our proposed LPPA.

中文翻译：

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LPPA：通过高效多密钥安全外包计算对 VANET 中基于位置的服务进行轻量级隐私保护身份验证


车载自组织网络 (VANET) 中的基于位置的服务 (LBS) 极大地受益于基于地理的社交网络的信息获取。认证保证了LBS信息的不可伪造性和有效性。不幸的是，由于车载自组网中传播大量冗余或无用的LBS消息，现有工作采用定期发布的认证密钥、消息标识符过滤或利用公钥（完全）同态加密（FHE）的认证开销很大，要么是资源有限的车载单元 (OBU) 无法忍受的，要么不适合 VANET 的实时控制要求。本文首先在云和密码服务提供商（CSP）两个非共谋服务器的设置下，提出了一种不利用公钥FHE的高效多密钥安全外包计算方案MSOC。然后，基于MSOC，设计了一种高效、安全的比较协议LSCP，无需服务器和用户之间的交互。此外，提出了一种用于车载网络中的LBS的轻量级隐私保护认证协议LPPA，通过新设计的高效隐私保护信息过滤系统，在执行认证之前消除重复和无用的加密LBS消息。即使作为云端（或CSP）的路边单元（RSU）与恶意用户串通，用户的位置隐私和兴趣隐私都得到了很好的保护。特别是，我们提出的MSOC的密文重加密特性也保证了两个用户是否接受相同的LBS信息的兴趣模式隐私。 最后，形式化的安全证明和广泛的仿真结果验证了我们提出的 LPPA 的有效性和实用性。