Immutability in Hyperledger Fabric

Question

Can someone explain how the immutability is implemented in Hyperledger Fabric? If we have a private channel with a little number of peers, how it can be guaranteed, that one side hasn't changed data in its ledger?

Answer 1

 To guarantee that no party in the channel has tampered data in its own favor you need to present sophisticated endorsement policy to include all required parties and make sure they adequately represented within endorsement policy. Hence making it obligatory for client which issues new transaction to get endorsement from all interested parties, hence ensuring that all have same consistent state.