Kaisa Nyberg
More info
- Affiliation
- Nokia Research Center, Aalto University
- Known for
- Differentially uniform S-boxes, Nyberg–Rueppel signature
Finnish cryptographer whose S-box construction ships inside every AES implementation on the planet.
Once differential cryptanalysis went public in 1990, Nyberg asked the constructive question: how do you build an S-box that provably resists it? Her 1993 paper on differentially uniform mappings showed that inversion in a finite field comes close to optimal. Rijndael adopted the construction wholesale, and with it AES.
With Lars Knudsen she designed the first cipher with a formal proof against differential attacks, and with Rainer Rueppel a signature scheme that recovers the message from the signature itself. She spent years at Nokia Research Center on mobile and Bluetooth security before becoming a professor at Aalto. A rare case of theory ending up in, quite literally, everyone's pocket.