Crispin Cowan is the security philosopher behind StackGard, the Immunix Linux distro, SubDomain and AppArmor which are said to be respected Linux-based security technologies. He entered the security arena in 1998 at the Seventh USENIX Security Symposium with the StackGuard paper, which introduced stack canaries for buffer overflow protection, a technique now used on nearly all platforms. From 1999 to 2007 he was the founding CTO of Immunix, which was acquired by Novell in 2005 to incorporate AppArmor into SUSE Linux.