On Risk-Based Authentication October 5, 2020 https://www.schneier.com/blog/archives/2020/10/on-risk-based-authentication.html Study: "More Than Just Good Passwords? A Study on Usability and Security Perceptions of Risk-based Authentication“ (PDF - 1.89 MB): https://riskbasedauthentication.org/download/rba-perceptions-paper.pdf