A network-connected device authentication system, the network-connected device authentication system comprising a processing resource configured to: provide a contracts database comprising a plurality of authentication-enabling information records, each authentication-enabling information record containing a network access descriptor of a respective network-connected device and reference values of respective authentication parameters of the respective network-connected device; obtain, from a requestor, an authentication request including a given network access descriptor associated with a given network-connected device to be authenticated; retrieve, from the given network-connected device, utilizing the given network access descriptor, a plurality of authentication values obtained by reading current values of the respective authentication parameters of the given network-connected device, wherein one or more given authentication parameters of the authentication parameters has a dynamic value that changes over time, and wherein at least one given authentication value of the authentication values, associated with a respective given authentication parameter, is obtained from a sensor connected to the given network-connected device; calculate an authentication grade indicative of authenticity of the given network-connected device by comparing each of the authentication values with a respective expected value, or expected value range, or a group of expected values, determined utilizing the respective reference values, wherein at least one of the reference values has been obtained by the sensor connected to the given network-connected device prior to obtaining its respective authentication value from the given network-connected device, and wherein the authentication grade depends on a distance between at least one of the expected values and its respective authentication value, the distance measured by a metric in a functional space; and send, to the requestor, an authentication reply. provide a contracts database comprising a plurality of authentication-enabling information records, each authentication-enabling information record containing a network access descriptor of a respective network-connected device and reference values of respective authentication parameters of the respective network-connected device; obtain, from a requestor, an authentication request including a given network access descriptor associated with a given network-connected device to be authenticated; retrieve, from the given network-connected device, utilizing the given network access descriptor, a plurality of authentication values obtained by reading current values of the respective authentication parameters of the given network-connected device, wherein one or more given authentication parameters of the authentication parameters has a dynamic value that changes over time, and wherein at least one given authentication value of the authentication values, associated with a respective given authentication parameter, is obtained from a sensor connected to the given network-connected device; calculate an authentication grade indicative of authenticity of the given network-connected device by comparing each of the authentication values with a respective expected value, or expected value range, or a group of expected values, determined utilizing the respective reference values, wherein at least one of the reference values has been obtained by the sensor connected to the given network-connected device prior to obtaining its respective authentication value from the given network-connected device, and wherein the authentication grade depends on a distance between at least one of the expected values and its respective authentication value, the distance measured by a metric in a functional space; and send, to the requestor, an authentication reply. <EOS>