A lightweight payment scheme for real-time services based on SIP

In the session initiation protocol (SIP), payments have been proposed as a way for vendors to obtain profit from the services they provide. Payments in SIP have also been proposed for microbilling and even as a solution to SPAM in VoIP systems. Although several proposals exist for making payments in SIP, they present some limitations when we want to pay for access to real-time services: either they are not suitable for micropayments or they do not consider security in the payment information exchanged. As a response to these limitations, we propose a new SIP payment protocol, LP-SIP, that supports the payment according to different models like pay-per-time, session-based, etc. It also performs payments in SIP efficiently and takes into account the secure exchange of payment information, unlike other existing proposals. Thus, we provide a lightweight payment protocol that can be used for the payment of real-time services.