Chapter 1 What’s New for FortiOS 5.2.1 : IPsec VPN : Internet Key Exchange (IKE) : Transform Matching
  
Transform Matching
FortiOS 5.2 supports combining multiple encryption, authentication, PRF, and DH transforms in a single IKEv2 proposal, which is used for selecting a transform set when the FortiGate unit is the responder. Each proposal now holds lists of transforms, instead of having just a single value per transform type. When negotiating, the proposal iterates over the transform lists to find a match.