Compact Signatures for Network Coding

Network coding offers increased throughput and improved robustness to random faults in completely decentralized networks. Since it does not require centralized control, network coding has been suggested for routing packets in ad-hoc networks, for content distribution in P2P file systems, and for improving the efficiency of large-scale data dissemination over the Internet. In contrast to traditional routing schemes, however, network coding requires intermediate nodes to process and modify data packets en route. For this reason, standard signature schemes are inapplicable and it is therefore a challenge to provide resilience to tampering by malicious nodes in the network. Here, we propose a novel homomorphic signature scheme that can be used in conjunction with network coding to prevent malicious modification of data. The overhead of our scheme is small and independent of the file or packet size: both public keys and signatures in our scheme consist of only a single group element.