A computer-implemented method for performing a remote attestation of a relay system node, the relay system node operating together with a relay system smart contract executing on a blockchain and a relay system controller as a relay system to relay data or requests from a client smart contract executing on the blockchain to a network and to relay data or request results from the network to the client smart contract, wherein the remote attestation for the relay system node results in a key pair for the relay system node and wherein the relay system smart contract is used for remote authentication of the relay system node, the method comprising: sending (410, 602), by the relay system controller and to the relay system node, an attestation request that requests an attestation evidence from the relay system node, the attestation evidence indicating a validity of the relay system node; receiving (414, 604), at the relay system controller and from the relay system node, an attestation evidence of the relay system node, the attestation evidence of the relay system node comprising a measurement value of the relay system node, a public key of the relay system node, and a digital signature of the relay system node, the public key of the relay system node being the public key of a key pair generated by the relay system node; sending (416, 606), by the relay system controller and to an attestation verification server, the attestation evidence of the relay system node; receiving (608, 422), by the relay system controller and from the attestation verification server, an attestation verification report, the attestation verification report comprising the attestation evidence of the relay system node, an attestation verification result, and a digital signature of the attestation verification server; sending (610, 424), by the relay system controller and to a relay system smart contract, the attestation verification report; determining, by the relay system smart contract, whether the attestation verification report is valid, the determining comprising at least one of the following: determining, by the relay system smart contract, whether the digital signature of the attestation verification server is valid; or determining, whether the measurement value of the relay system node that is in the attestation verification report matches a measurement value of the relay system node that the relay system smart contract obtains from the relay system node; in response to determining that the attestation verification report is valid, determining, by the relay system smart contract, that the public key of the relay system node is valid; and storing, by the relay system smart contract, the public key of the relay system node in the relay system smart contract. sending (410, 602), by the relay system controller and to the relay system node, an attestation request that requests an attestation evidence from the relay system node, the attestation evidence indicating a validity of the relay system node; receiving (414, 604), at the relay system controller and from the relay system node, an attestation evidence of the relay system node, the attestation evidence of the relay system node comprising a measurement value of the relay system node, a public key of the relay system node, and a digital signature of the relay system node, the public key of the relay system node being the public key of a key pair generated by the relay system node; sending (416, 606), by the relay system controller and to an attestation verification server, the attestation evidence of the relay system node; receiving (608, 422), by the relay system controller and from the attestation verification server, an attestation verification report, the attestation verification report comprising the attestation evidence of the relay system node, an attestation verification result, and a digital signature of the attestation verification server; sending (610, 424), by the relay system controller and to a relay system smart contract, the attestation verification report; determining, by the relay system smart contract, whether the attestation verification report is valid, the determining comprising at least one of the following: determining, by the relay system smart contract, whether the digital signature of the attestation verification server is valid; or determining, whether the measurement value of the relay system node that is in the attestation verification report matches a measurement value of the relay system node that the relay system smart contract obtains from the relay system node; determining, by the relay system smart contract, whether the digital signature of the attestation verification server is valid; or determining, whether the measurement value of the relay system node that is in the attestation verification report matches a measurement value of the relay system node that the relay system smart contract obtains from the relay system node; in response to determining that the attestation verification report is valid, determining, by the relay system smart contract, that the public key of the relay system node is valid; and storing, by the relay system smart contract, the public key of the relay system node in the relay system smart contract.