Where do smart contracts reside in blockchain (Ethereum or Hyperledger)

Question

So, let us consider a typical trade finance process flow. Exporter deploys a contract that has conditions of the shipment and a hash is generated once the deployment is fini

Answer 1

1) The contract resides on the ledger. Whenever a transaction is invoked, the corresponding method in the contract gets executed on all the validating peers.

2) Other participants can access this contract using their pre-defined user credentials, which they can use to enroll themselves and invoke transactions on the contract.

3) Yes, we can activate participant level access to the contract by defining attributes for every user and allowing only those users who possess certain attributes to access specific parts of the contract.