I'm trying to understand if security is a real concern, or if distribution actually does a better job with security. See, the access to the main source repository could be layered and inherently managed by a network of trust, and could still have centralized user management integrating users from an LDAP/Active Directory, while the centralized version control system just relies on the later. With distribution, access could even be given to less users per repository in different countries and maintained easier.
I can see why it is easy to think that having tight & centralized access management to a code repository translates to security, however, that doesn't mean that code cannot be accessed or redistributed other ways. But, is there a real argument/use case/scenario for security where the centralized model is just better than the distributed one?.
Some context: I'm trying to make the case (with a whitepaper) to my company to switch to a DVCS (I already have other problems identified that are successfully addressed by most DVCSs) and security is one of the arguments I'm expecting to have to justify. My company is open minded though; they currently use perforce and are distributed geographically.