A client device in an information delivery system, the client device comprising: a control unit configured to: generate an anonymous identity for concealing client information of an anonymous client from a provider, the anonymous identity including a client testable representation; generate a client first encryption data by encrypting the client testable representation with a client key; receive a provider first encryption data comprising a provider testable representation encrypted with a provider key; generate a provider second encryption data by encrypting the provider first encryption data with the client key; generate a comparison result for determining whether a client second encryption data matches with the provider second encryption data, the client second encryption data comprising the client first encryption data encrypted with the provider key; and obtain a provider notification based on the comparison result of a match for displaying on a device; and a user interface, coupled to the control unit, configured to display the provider notification; wherein the provider testable representation comprises a representation of a provider location abstraction or a provider promotion abstraction; and wherein the client testable representation comprises a representation of a client location abstraction or a client interest abstraction. a control unit configured to: generate an anonymous identity for concealing client information of an anonymous client from a provider, the anonymous identity including a client testable representation; generate a client first encryption data by encrypting the client testable representation with a client key; receive a provider first encryption data comprising a provider testable representation encrypted with a provider key; generate a provider second encryption data by encrypting the provider first encryption data with the client key; generate a comparison result for determining whether a client second encryption data matches with the provider second encryption data, the client second encryption data comprising the client first encryption data encrypted with the provider key; and obtain a provider notification based on the comparison result of a match for displaying on a device; and generate an anonymous identity for concealing client information of an anonymous client from a provider, the anonymous identity including a client testable representation; generate a client first encryption data by encrypting the client testable representation with a client key; receive a provider first encryption data comprising a provider testable representation encrypted with a provider key; generate a provider second encryption data by encrypting the provider first encryption data with the client key; generate a comparison result for determining whether a client second encryption data matches with the provider second encryption data, the client second encryption data comprising the client first encryption data encrypted with the provider key; and obtain a provider notification based on the comparison result of a match for displaying on a device; and a user interface, coupled to the control unit, configured to display the provider notification; wherein the provider testable representation comprises a representation of a provider location abstraction or a provider promotion abstraction; and wherein the client testable representation comprises a representation of a client location abstraction or a client interest abstraction.