How to prevent the smart contract from being modified and deployed in Hyperledger network

Question

I understand that in permissioned networks such as Hyperledger and Corda, some programs such as smart contracts/chaincodes allow us to implement the business logic. And this is deployed on each peer on the network, but how is it verified that the same code is deployed on all peers and is not altered?

Answer 1

Smart contracts can be definitive if they are both signed by a valid digital signature and are deterministic.

The presence of a digital signature provides a mechanism to all nodes to allow them to determine whether the contract code has been manipulated.

If the smart contract code is deterministic, all nodes that execute the code will arrive at the same final state.

each state in a transaction is associated with a given contract. This contract is uniquely identified using a [contract name, hash of the JAR file containing the contract] pair.

If the contract is modified, this will modify the hash of the JAR containing the contract, and thus the contract JAR will no longer be considered valid.