A system comprising: a telecommunication provider server configured for detecting a location of a mobile device; a host server configured for conducting, with the mobile device, an electronic transaction within an interactive computing environment accessible over a data network; and an identification-and-authentication system communicatively coupled to the host server via a first communication channel and the telecommunication provider server via a second communication channel that is out-of-band with respect to the first communication channel, wherein the identification-and-authentication system is configured for: obtaining, via the first communication channel, a data network identifier that identifies the mobile device, generating, based on communications with the telecommunication provider server via the second communication channel, a dynamic identity-verification element comprising the data network identifier and a location identifier that identifies a geographic location of the mobile device, computing, from the dynamic identity-verification element, an indicator of unauthorized use of the host server by the mobile device; and automatically transmitting a control signal to the host server, wherein the host server is further configured for preventing, Lilting, responsive to the control signal, the mobile device from accessing a function for advancing the electronic transaction within the interactive computing environment; characterised in that computing the indicator of the unauthorized use comprises: configuring a network interface device to transmit, to the host server, a validation request having the location identifier; wherein the validation request comprises coordinates of the mobile device, a distance between the mobile device and a location associated with the host server, or some combination thereof; and determining, from a response to the validation request, that the location of the mobile device is invalid. a telecommunication provider server configured for detecting a location of a mobile device; a host server configured for conducting, with the mobile device, an electronic transaction within an interactive computing environment accessible over a data network; and an identification-and-authentication system communicatively coupled to the host server via a first communication channel and the telecommunication provider server via a second communication channel that is out-of-band with respect to the first communication channel, wherein the identification-and-authentication system is configured for: obtaining, via the first communication channel, a data network identifier that identifies the mobile device, generating, based on communications with the telecommunication provider server via the second communication channel, a dynamic identity-verification element comprising the data network identifier and a location identifier that identifies a geographic location of the mobile device, computing, from the dynamic identity-verification element, an indicator of unauthorized use of the host server by the mobile device; and automatically transmitting a control signal to the host server, wherein the host server is further configured for preventing, Lilting, responsive to the control signal, the mobile device from accessing a function for advancing the electronic transaction within the interactive computing environment; characterised in that computing the indicator of the unauthorized use comprises: configuring a network interface device to transmit, to the host server, a validation request having the location identifier; wherein the validation request comprises coordinates of the mobile device, a distance between the mobile device and a location associated with the host server, or some combination thereof; and determining, from a response to the validation request, that the location of the mobile device is invalid. obtaining, via the first communication channel, a data network identifier that identifies the mobile device, generating, based on communications with the telecommunication provider server via the second communication channel, a dynamic identity-verification element comprising the data network identifier and a location identifier that identifies a geographic location of the mobile device, computing, from the dynamic identity-verification element, an indicator of unauthorized use of the host server by the mobile device; and automatically transmitting a control signal to the host server, wherein the host server is further configured for preventing, Lilting, responsive to the control signal, the mobile device from accessing a function for advancing the electronic transaction within the interactive computing environment; characterised in that computing the indicator of the unauthorized use comprises: configuring a network interface device to transmit, to the host server, a validation request having the location identifier; wherein the validation request comprises coordinates of the mobile device, a distance between the mobile device and a location associated with the host server, or some combination thereof; and determining, from a response to the validation request, that the location of the mobile device is invalid. configuring a network interface device to transmit, to the host server, a validation request having the location identifier; wherein the validation request comprises coordinates of the mobile device, a distance between the mobile device and a location associated with the host server, or some combination thereof; and determining, from a response to the validation request, that the location of the mobile device is invalid.