Is it possible to transfer assets which requires the private key of a third party person and not the current asset owner?

hi, Needed some help on 2 questions 
1.Is it possible to transfer assets which requires the private key of a third party person and not the current asset owner. To elaborate here is an example ..Party A creates an asset and is the owner but i require that ONLY Party B who is not an owner of the asset be able to make a successful transfer of asset from party A to party C. I believe this could be done using custom crypto condistions but am not sure as the person i want to authorise transfers is not a owner of the asset. 
2.WHich brings me to my next question if it is possible where can i find some elaborate reading material on cryptoconditions. Thankyou