Tal Rabin
Cryptographer who turned threshold cryptography and secure multiparty computation into things you can build, not merely prove.
With Michael Ben-Or, Rabin showed in 1989 that a group can jointly compute a function of their private inputs as long as a majority is honest — one of the foundational results of secure multiparty computation, resting on verifiable secret sharing.
For many years she led the cryptography group at IBM Research, where work on threshold signatures — a key spread out so that no single server can sign alone — gained practical weight. She has also been a prominent voice for bringing more women into the field. Her father is Michael Rabin, so dinner-table arguments were presumably somewhat asymmetric.