A node provides a service to a client node in a network. The node is configured to execute a code for providing the service to the client node in an enclave of a trusted execution environment (TEE) and to execute a code library in the enclave to attest to the client node the identity of the service provided. The service provided to the client node may be a distributed service including a result of a cooperation of a plurality of neighbor nodes, which are connected to the node either directly or through other intermediate nodes. The code library is configured to attest to the client node the identity of the distributed service.