2021.05.15 21:47:05 (1393654184222728193) from Daniel J. Bernstein:
Looks like it's time for a new burst of papers from cryptographers analyzing how privacy-preserving contact-tracing systems can be extended to recognize that you were in a room from 11:00 to 11:30 and someone infected was in that room from 10:15 to 10:45. https://www.wired.com/story/the-teeny-tiny-scientific-screwup-that-helped-covid-kill/