A method, in a communication network wherein a first computing device is a client device, a second computing device is an application server, and a third computing device is a server under control of an operator of the communication network, the method comprising: the first computing device issuing a resource request to the second computing device and the first computing device providing a first identifier to the second computing device for use in authenticating the first computing device to the second computing device; in response to the second computing device being unable to authenticate the first computing device, said second computing device sending a response to the first computing device that comprises the first identifier; and in response to the first computing device receiving the response that comprises the first identifier, the first computing device sending an authentication request to the third computing device, the third computing device checking for a correlation between a second identifier used by the first computing device to access the communication network as a subscriber and the first identifier sent by the first computing device, and the third computing device assisting in the authentication of the first computing device to the second computing device when the correlation exists, wherein upon a successful authentication exchange between the first computing device and the third computing device comprising a pre-computed challenge and response, the third computing device sending a cryptographically-signed authentication result to the first computing device with redirection to the second computing device, such that the first computing device sends the cryptographically-signed authentication result to the second computing device and the second computing device is able to reply to the resource request sent by the first computing device. the first computing device issuing a resource request to the second computing device and the first computing device providing a first identifier to the second computing device for use in authenticating the first computing device to the second computing device; in response to the second computing device being unable to authenticate the first computing device, said second computing device sending a response to the first computing device that comprises the first identifier; and in response to the first computing device receiving the response that comprises the first identifier, the first computing device sending an authentication request to the third computing device, the third computing device checking for a correlation between a second identifier used by the first computing device to access the communication network as a subscriber and the first identifier sent by the first computing device, and the third computing device assisting in the authentication of the first computing device to the second computing device when the correlation exists, wherein upon a successful authentication exchange between the first computing device and the third computing device comprising a pre-computed challenge and response, the third computing device sending a cryptographically-signed authentication result to the first computing device with redirection to the second computing device, such that the first computing device sends the cryptographically-signed authentication result to the second computing device and the second computing device is able to reply to the resource request sent by the first computing device.