This is taken from an article written in 1999 but it’s such a well-written article and so informative, that I could not help posting it here. Here’s an excerpt:
As a cryptography and computer security expert, I have never understood the current fuss about the open source software movement. In the cryptography world, we consider open source necessary for good security; we have for decades. Public security is always more secure than proprietary security. It’s true for cryptographic algorithms, security protocols, and security source code. For us, open source isn’t just a business model; it’s smart engineering practice.
Read Open Source and Security by Bruce “Dr. Security” Schneier.