# Miyaji Laboratory

Network coding has been proposed as an alternative to the traditional store-and-forward paradigm in networks. It allows the intermediate nodes to combine the received data before forwarding them. This technique has been shown to improve throughput and robustness. Due to its features, network coding has already found applications in distributed storage, P2P content distribution, wireless networks, etc. However, network coding systems are vulnerable to pollution attacks, where malicious nodes inject corrupted packets into the network. Corrupted packets propagate in an epidemic manner, depleting network resources and significantly decreasing throuput. In a worst case scenario, a single corrupted packet can end up corrupting all the information reaching a destination. This wastes network resources, such as bandwidth and CPU time, and eventually prevents the decoding of the original packets at the receivers. To detcting pollution attacks, intermediate node have to check the integrity of the packet. However, network coding cannot be mitigated by traditional signatures, e.g., DSA, or MACs, e.g, HMAC. A large body of work has focused on pollution attacks in single source coding, while pollution attacks in multi source coding have received significantly less attention. Wu et al. proposed HYBRID scheme for single source network coding. In HYBRID scheme, the use of $N$ keys allows $N-1$ nodes be compromised. In this paper, we show HYBRID scheme for multi source network coding by using private inner product protocol.