Kaisa Nyberg is a Finnish cryptographer and computer security researcher.
Nyberg's research includes the theory of perfect nonlinear S-boxes[N] (now known as Nyberg S-boxes),[1] provably secure block cipher design (resulting in KN-Cipher[2][NK], and the cryptanalysis of the stream ciphers E0[HN] and SNOW[B+]).
Her dissertation, On Subspaces of Products of Nuclear Fréchet Spaces, was in topology, and was supervised by Edward Leonard Dubinsky.
[3] Nyberg began doing cryptography research for the Finnish Defence Forces in 1987, and moved to Nokia in 1998.
[4] Nyberg was the 2015 recipient of the Magnus Ehrnrooths Foundation Prize of the Finnish Society of Arts and Letters.