The anonymous credential literature is filled with variants of the above approaches, sometimes combinations of the three. In every case, the goal is to put some barriers in the way of credential cloning.
Hands-on: Motorola unveils Razr Fold, a book-style foldable phone
，更多细节参见下载安装 谷歌浏览器 开启极速安全的 上网之旅。
Фото: Екатерина Чеснокова / РИА Новости
只不过，「搓擦条」的最终成品相当别扭，还要单独适配，导致开发者兴趣寥寥，用户能实际得益于触控的场景也非常有限。但如今，整块屏幕都可以触控，用户想怎么用就怎么用，反而从根本上解决了交互设计的问题——毕竟，谁不会用 iPhone 和 iPad 呢？
Tony Jolliffe/BBC News