中文摘要：

第三方追踪可以获得用户的浏览历史等隐私信息,如何保护第三方追踪带来的隐私威胁问题成为安全领域的重要研究内容.首先介绍第三方追踪的基本概念、特点及安全现状,并结合第三方应用的类型,总结了第三方追踪存在的隐私威胁.然后从有状态追踪和无状态追踪2个方面介绍第三方追踪的技术,并对第三方追踪防御的相关研究进行了分析和比较.最后总结第三方追踪中研究领域的开放性问题和发展方向.

英文摘要：

Third-party tracking can record users＇ behaviors across many websites.Increasing attention has been paid to the area of third-party tracking due to the fact that user＇s privacy protection is causing wider concern.The basic concept and present development were introduced.And security risks were also summarized.Then main technology of third-psrty tracking was intrduced from stateful tracking and stateless tracking aspects.Furthermore,several existing defenses of third-party tracking were described and compared.Finally,some hot research topics were given and the future research directions were discussed.