The cloud security conundrum: de-perimeterisation or re-perimeterisation?

The cloud is, perhaps, the epitome of de-perimeterisation. If you take the definition of this being the removal of boundaries between the enterprise and the outside world it's pretty much bang on the money. It's easy to assume, therefore, that de-perimeterisation in the information security sense is the answer to your cloud security concerns. It isn't, at least not the complete answer. For the more rounded solution you need to throw re-perimeterisation into the mix and let the two bang heads. I appreciate that this sounds more than a little contradictory, but when you think about it there is plenty of method in the apparent anarchic madness.