Marcus Ranum

Marcus Ranum is a computer security expert. He worked for Digital Equipment where he implemented the first commercially available firewall product, SEAL. He later worked at Trusted Information Systems, where he designed the firewall for the whitehouse.gov site and the TIS firewall toolkit which evolved into the Gauntlet firewall. He founded the company Network Flight Recorder and designed their main product, an intrusion detection system. As of mid-2010, he is at Tenable Security.

He has a web site; well-known pages there include a One-time pad FAQ and one on the ultimate firewall.