I hope that after 9/11 people don't think that closed source means secret and more secure. In reality, the most secure systems available today are based on the open source model and peer review. There is absolutely no question that the secret to creating great software that is also secure software is by marshalling as many smart people as possible to the task.

Traditionally, software security was equated with secrecy. You lock up your house, your car and your valuables. In the software community, you "lock up" the programming source code as a means of securing it against hackers and competitors. To the closed source camp, a system can't be truly secure when its source is open for all to read. Secrecy is security, and when applied to an otherwise secure system, concealing the source improves the security. It slows up intruders and, in the event of a breech, keeps damages at a minimum. Another argument is that with freely available blueprints, crackers will have it easy writing malicious code to attack systems.