Within UDC platform, account is a group of DC elements those belongs to some owner(s).
Each approved person and organization has a default account to control and operate DCs. The whole account balance is a sum of all active DCs belonging to the account. Transferring DC is in fact an operation to change the account of the corresponding DC contracts. DC contract only allows transfer between proper accounts. Also, the signature of the contract owner is checked to ensure the owner has approved the transfer.