The remarkable growth of the Internet as a data transmission medium has in part been enabled by the simplicity and scalability of the core Internet Protocol (IP), which is used for addressing and routing data packets through the network. The IP service includes different model based on the application field in which it is implemented. IP multicast is undoubtedly an innovating area of IP services available today. IP Multicast capable network is increasingly becoming an important technology for commercial and even military distributive and group-based application. Multicast enables efficient group communication by allowing the sender to transmit a single copy of data, with network components such as routers and switches making copies as necessary for the receivers. In other hand, in spite of the vast amount of research and important raise of IP multicast protocols, the implementations of multicast applications have been slow. The major factor of this situation is that the multicast services lack support for traffic management, reliability and security. We identify IP multicast security as one of the key issues for the successful deployment of the group communication applications. In many ways, the IP multicast implementation and its security are then still at their infantile state. Put them together into Multicast Security, and we may have many original but interesting problems. The most challenging defy is the source authentication that presents a contradictory requirement on the computational and communication overhead. Thus mitigating solutions are necessary to resolve this problem. Those solutions presently used the amortization method to overcome the issue. But the annoyance in those solutions is that,for most of the existing methods the amortization of one side will imply higher overhead at the other side. This study is motivated by this trend and it investigates amortizations methods used in the source authentication of IP multicast by their conceptual architecture. We then proceed to an analytic investigation of the Information Dispersal Algorithm method utilized to come over the authentication overhead amortizations challenges, and propose some technical amelioration to it.