How easy is it to uniquely identify a person based on their web browsing behavior? Here we show that when people navigate the Web, their online traces produce fingerprints that identify them. By merely knowing their most visited web domains, four data points are enough to identify 95% of the individuals. These digital fingerprints are stable and render high re-identifiability. We demonstrate that we can re-identify 90% of the individuals in separate time slices of data. Such a privacy threat persists even with limited information about individuals' browsing behavior, reinforcing existing concerns around online privacy.

翻译：通过用户的网页浏览行为，能否轻易地唯一识别一个人的身份？本研究表明，当人们在网络上浏览时，其在线痕迹会生成可识别身份的指纹。即便仅知道用户最常访问的网站域名，仅需四个数据点即可识别出95%的个体。这些数字指纹具有稳定性，并展现出高度的再识别能力。我们证明，在独立的数据时间片中，能够重新识别出90%的个体。即便仅掌握个体浏览行为的有限信息，这种隐私威胁依然存在，这进一步加剧了人们对在线隐私的既有担忧。