Authenticating real time packet streams and multicasts

We propose a new stream authentication scheme that is suitable for live packet streams distributed over a lossy channel, such as an IP-multicast group. Packets are signed together in a block and the recipient can authenticate this block if the loss rate per block is lower than a certain threshold, which can be chosen based on the characteristic of the communication channel. This scheme provides both integrity and non repudiation of origin, and in a majority of situations, it performs with less overhead in bytes per packet than previously proposed practical live stream authentication schemes.