Claudia Díaz
Spanish researcher at KU Leuven who made anonymity measurable and later co-founded the Nym mixnet.
In 2002 Díaz, with co-authors including Bart Preneel, published one of two simultaneous proposals to measure anonymity with entropy. Instead of asking whether a user is anonymous, you ask how evenly an attacker's suspicion is spread across all possible senders. Suddenly systems like Crowds, Tor and mixnets could be compared on the same scale.
She has since worked on traffic analysis, privacy-by-design and the mix networks David Chaum sketched back in 1981. As a co-founder of Nym she tried to turn that theory into a working network, an ongoing experiment in how much latency people will actually tolerate for their privacy.