Security in open versus closed systems—the dance of Boltzmann, Coase and Moore

Some members of the open-source and free software com- munity argue that their code is more secure, because vulnerabilities are easier for users to find and fix. Meanwhile the proprietary vendor com- munity maintains that access to source code rather makes things easier for the attackers. In this paper, I argue that this is the wrong way to approach the interaction between security and the openness of design. I show first that under quite reasonable assumptions the security assur- ance problem scales in such a way that making it either easier, or harder, to find attacks, will help attackers and defendants equally. This model may help us focus on and understand those cases where some asymmetry is introduced.
However, there are more pressing security problems for the open source community. The interaction between security and openness is entangled with attempts to use security mechanisms for commercial advantage – to entrench monopolies, to control copyright, and above all to control interoperability. As an example, I will discuss TCPA, a recent initiative by Intel and others to build DRM technology into the PC platform. Al- though advertised as providing increased information security for users, it appears to have more to do with providing commercial advantage for vendors, and may pose an existential threat to open systems.