Online Social Networks (OSNs) offer free storage and social networking services through which users can communicate personal information with one another. The personal information of the users collected by the OSN provider comes with privacy problems when being monetized for advertising purposes. To protect user privacy, existing studies propose utilizing data encryption that immediately prevents OSNs from monetizing users data and hence leaves secure OSNs with no convincing commercial model. To address this problem, we propose Privado as a privacy-preserving group-based advertising mechanism to be integrated into secure OSNs to re-empower monetizing ability. Privado is run by N servers, each provided by an independent provider. User privacy is protected against an active malicious adversary controlling N − 1 providers, all the advertisers, and a large fraction of the users. We base our design on the group-based advertising notion to protect user privacy, which is not possible in the personalized variant. Our design also delivers advertising transparency; the procedure of identifying target customers is operated solely by the OSN servers without getting users and advertisers involved. We carry out experiments to examine the advertising running time under various number of servers and group sizes. We also argue about the optimum number of servers with respect to user privacy and advertising running time.

中文翻译：

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私下

在线社交网络 (OSN) 提供免费的存储和社交网络服务，用户可以通过这些服务相互交流个人信息。OSN 提供商收集的用户个人信息在被用于广告目的的货币化时会出现隐私问题。为了保护用户隐私，现有研究建议利用数据加密立即阻止 OSN 将用户数据货币化，从而使安全的 OSN 没有令人信服的商业模型。为了解决这个问题，我们建议将 Privado 作为一种基于组的隐私保护广告机制，以集成到安全的 OSN 中，以重新增强货币化能力。Privado 由ñ服务器，每个都由独立的提供商提供。保护用户隐私免受活跃的恶意对手控制ñ− 1 个提供商、所有广告商和大部分用户。我们的设计基于基于群组的广告概念，以保护用户隐私，这在个性化变体中是不可能的。我们的设计还提供广告透明度；识别目标客户的过程完全由 OSN 服务器操作，不涉及用户和广告商。我们进行实验以检查在不同数量的服务器和组大小下的广告运行时间。我们还讨论了关于用户隐私和广告运行时间的最佳服务器数量。