SAN JOSE, Calif. -- Sun Microsystems' CEO Scott McNealy strongly aligned his company with open-source software as a way to compete with rival Microsoft on the battleground of software security.

During a keynote presentation on Tuesday, McNealy took proprietary software to task, equating a closed development process with the creation of software vulnerabilities that lead to security breaches. Always combative, McNealy argued that his company--which has released the code for Solaris and donated several projects, most notably OpenOffice, to the open-source community--took a founding role in the creation of the open-source community.

"Every interface that we have developed, that has been user visible, has been open since 1982," McNealy told attendees at the RSA Conference here. "It is a little Al Gore-ish to say we have created open-source software, but we did. Berkeley Unix was the first real major effort at an open-source kernel. We were the Red Hat of Berkeley Unix before anyone really talked about it."

While Sun has supported open-source software in many ways, the company has also seen its share of the server market undercut by cheaper Unix-like systems running Linux. In a move widely seen as negative for open-source efforts, the company also signed a deal with the SCO Group--which has claimed that its licenses covering Unix also cover Linux--to protect Sun against any possible lawsuit.

Security experts continue to debate the merits of open-source software and proprietary software. Open-source advocates argue that public code means bugs are found quicker, while proprietary advocates argue that expert quality control can create more secure code without tipping off potential attackers to the weaknesses in the program.