The multi-party transaction

At the heart of a business network implemented in Hyperledger Fabric is a multi-party transaction. This single idea allows us to understand the entire philosophy of Hyperledger Fabric, so it's right to spend a little time making sure we fully grasp this concept.

The good news is that a multi-party transaction is a powerfully simple idea. As we explained in Chapter 3, Business Networks, a multi-party transaction describes the change in a set of business objects involving two or more participants.

In the following code, we can see an example of a multi-party transaction that describes the transfer of a car between two participants: Sara Seller and Bob Buyer (we've given them alliterative names to help us recall their roles):

car transfer transaction:
 identifier: 1234567890
 proposal: 
  input: {CAR1, Sara Seller, Bob Buyer}
  signature: input signed by Sara Seller
 response: 
  output: 
    {CAR1.currentOwner = Sara Seller, 
     CAR1...