Markus Friedl
German OpenBSD developer, one of OpenSSH's founders, and the person who taught it the second version of the SSH protocol.
When Tatu Ylönen's SSH went proprietary, the OpenBSD crowd picked up an older free release in 1999 via Björn Grönvall's OSSH and cleaned it up into OpenSSH. Friedl was part of the small founding group alongside Theo de Raadt, Niels Provos and a few others.
The first release only spoke SSH-1, a protocol with known weaknesses. Friedl wrote the SSH-2 support that shipped in OpenSSH 2.0 in 2000, making the free implementation viable for the protocol that went on to become the standard. Without it, OpenSSH would have remained a hobby project tied to a dying protocol.