James Massey
American information theorist in Zurich who gave the world the Berlekamp–Massey algorithm and, with a PhD student, the IDEA block cipher.
In 1969 Massey (1934–2013) showed that Berlekamp's decoding algorithm could find the shortest linear feedback shift register generating a given sequence — which turned it into a weapon against weak stream ciphers. He was a professor at ETH Zurich from 1980 and won the Shannon Award in 1988.
With his student Xuejia Lai he designed PES in 1990 and its hardened successor IDEA in 1991, which mixed three mutually incompatible algebraic operations instead of using S-boxes. IDEA became PGP's default cipher. For Cylink he designed the SAFER family. That one of the most widely used ciphers of the nineties came from a coding theorist says a lot about how close the two fields sit.