Abstract: In the location based service (LBS), trusted third party model is the main model of current location privacy protection. The anonymous server in this model knows the user’s location, if it is attacked, which will cause the leakage of the user's location information. Therefore, this paper puts forward a location privacy protection method based on grid. The method replaces the trusted third party (TTP) as a semi-trusted third party (STTP), which is a matching server. The matching server only matches and caches, and cannot know the user??s location, so as to protect user's location privacy better. Security analysis shows that this method can effectively protect the user??s location privacy. At the same time, this paper compares this method with trusted third party model. The experimental results show that the performance of this method is better than trusted third party model.

Key words: location-based service, location privacy protection, grid, semi-trusted third party

摘要： 在基于位置的服务（location based service，LBS）中，可信第三方模型是当前位置隐私保护中的主要模型，该模型中匿名器知道用户的具体位置，若它被攻击者攻破，将会造成用户位置信息的泄露。为此，提出一种基于网格的位置隐私保护方法，该方法将可信第三方模型中可信的第三方（trusted third party，TTP）替换为一个半可信的第三方（semi-trusted third party，STTP）作为匹配服务器。该匹配服务器只起匹配和缓存的作用，无法获得用户具体位置，从而能够更好地保护用户的位置隐私。安全分析表明，该方法能有效保护用户的位置隐私；同时与可信第三方模型进行了对比分析，实验结果表明，其性能比可信第三方模型更好。

关键词: 基于位置的服务, 位置隐私保护, 网格, 半可信第三方