Scott Vanstone
Canadian mathematician who took elliptic curve cryptography from journal paper to phones, smart cards and standards.
Koblitz and Miller proposed elliptic curves for cryptography in 1985, but it was Vanstone at the University of Waterloo who turned them into a business. He co-founded Certicom, which spent the 1990s pushing ECC into standards and accumulating hundreds of patents. In 1992 he proposed ECDSA, the signature scheme that now protects everything from TLS to Bitcoin.
With Alfred Menezes and Paul van Oorschot he wrote the Handbook of Applied Cryptography (1996), still free online and still cited. Certicom was bought by BlackBerry maker RIM in 2009. The patent portfolio kept many implementers on RSA long after curves were technically better — an irony Vanstone lived to see resolved before he died in 2014.