Homomorphic MACs: MAC-Based Integrity for Network Coding

Abstract. Network coding has been shown to improve the capacity and robustness in networks. However, since intermediate nodes modify packets en-route, integrity of data cannot be checked using traditional MACs and checksums. In addition, network coded systems are vulnerable to pollution attacks where a single malicious node can flood the network with bad packets and prevent the receiver from decoding the packets correctly. Signature schemes have been proposed to thwart such attacks, but they tend to be too slow for online per-packet integrity. They also force network coding coefficients to be picked from a large field which causes the size of the network coding header to be large. Here we propose a homomorphic MAC which allows checking the integrity of network coded data. Our homomorphic MAC is designed as a drop-in replacement for traditional MACs (such as HMAC) in systems using network coding.

• Type: Conference
• Year: 2009
• Where: ACNS
• Authors: Shweta Agrawal, Dan Boneh
• Keywords: ACNS 2009, Cryptography, Network Coding, Nodes Modify Packets, Traditional Macs