Multicasting is increasingly used as an efficient communication mechanism for group-oriented applications in the internet. As a result, more and more attention is paid on secure multicast communication. While peer-to-peer security is a mature and well developed field, secure group communication remains relatively unexplored. As one of the most key problems of secure multicast, source authentication becomes the research hotspot in recent years. In this paper, the existing source authentication schemes are briefly reviewed and a novel source authentication scheme based on stream authentication is proposed. Through introducing receivers' feedback mechanism on packet verification probability in the network, we can adjust the algorithm timely to fit the actual network state. We also proposed an optimized hash algorithm with lower computation overhead and communication overhead. Moreover, it can accelerate the authentication process both in Sender and Receiver. Compared with the other schemes with similar structure, it is more efficient.