A computing system comprising: a telecommunication provider server configured for providing telecommunication service to a mobile device; a host server configured for conducting, with the mobile device, an online transaction within an interactive computing environment accessible over a data network; and an identification-and-authorization system communicatively coupled to (i) the host server via a first communication channel and (ii) 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-authorization system is configured for: obtaining, via the first communication channel, a data network identifier that identifies the mobile device, obtaining, from communications with the telecommunication provider server via the second communication channel, a credential corresponding to the data network identifier, matching the credential to a set of multiple authorization elements, wherein each of the authorization elements is configured to provide the mobile device with access to a function for advancing the online transaction within the interactive computing environment, generating a dynamic authorization data structure comprising (i) the data network identifier and (ii) the set of multiple authorization elements, and automatically transmitting, to the host server, a control signal having dynamic authorization data structure, wherein the host server is further configured for: providing a selection interface to the mobile device, wherein the selection interface presents partially masked versions of the authorization elements, and advancing, responsive to receiving a selection of one of the partially masked versions of the authorization elements from the mobile device, the online transaction within the interactive computing environment. a telecommunication provider server configured for providing telecommunication service to a mobile device; a host server configured for conducting, with the mobile device, an online transaction within an interactive computing environment accessible over a data network; and an identification-and-authorization system communicatively coupled to (i) the host server via a first communication channel and (ii) 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-authorization system is configured for: obtaining, via the first communication channel, a data network identifier that identifies the mobile device, obtaining, from communications with the telecommunication provider server via the second communication channel, a credential corresponding to the data network identifier, matching the credential to a set of multiple authorization elements, wherein each of the authorization elements is configured to provide the mobile device with access to a function for advancing the online transaction within the interactive computing environment, generating a dynamic authorization data structure comprising (i) the data network identifier and (ii) the set of multiple authorization elements, and automatically transmitting, to the host server, a control signal having dynamic authorization data structure, obtaining, via the first communication channel, a data network identifier that identifies the mobile device, obtaining, from communications with the telecommunication provider server via the second communication channel, a credential corresponding to the data network identifier, matching the credential to a set of multiple authorization elements, wherein each of the authorization elements is configured to provide the mobile device with access to a function for advancing the online transaction within the interactive computing environment, generating a dynamic authorization data structure comprising (i) the data network identifier and (ii) the set of multiple authorization elements, and automatically transmitting, to the host server, a control signal having dynamic authorization data structure, wherein the host server is further configured for: providing a selection interface to the mobile device, wherein the selection interface presents partially masked versions of the authorization elements, and advancing, responsive to receiving a selection of one of the partially masked versions of the authorization elements from the mobile device, the online transaction within the interactive computing environment. providing a selection interface to the mobile device, wherein the selection interface presents partially masked versions of the authorization elements, and advancing, responsive to receiving a selection of one of the partially masked versions of the authorization elements from the mobile device, the online transaction within the interactive computing environment.