With Diablo III still at the grindstone Blizzard has also been hard at work on the new Battle.net code which will help eliminate scurvy cheaters.
A lot of the lessons have been learned from World of Warcraft as Blizzard is locked in a never ending battle with exploiters. Cheat prevention is one of their "biggest focuses."
Taken from Diabloiii.net's round-up of Battle.net 2.0 features:
Hack-Free
As Blizzard is learning from WoW when it comes to server infrastructure where they are battling hackers and exploiters, the new Battle.net will be built on programming that prevent any form of hacking or cheating. Taking several lessons from WoW in that regard, "duping" in Diablo III will be come impossible. Chris Sigaty promised me that they will ensure security as best we can, to keep it fair for all players. The Blizzard Accounts will also encourage people to be more responsible online.
Blizzard themselves haven't commented much on the precise method of security as it would be rather silly to spill secrets on just how you intend to stop hacks.
Source: VE3D