C. Gkantsidis and P. Rodriguez
Peer-to-peer content distribution networks can suffer from malicious participants that intentionally corrupt content. Some systems such as BitTorrent verify blocks with traditional cryptographic signatures and hashes. However, these techniques do not apply well to more elegant systems that use network coding techniques for efficient content distribution. Architectures that use network coding are prone to jamming attacks where the introduction of a few corrupted blocks can quickly result in a large number of bad blocks propagating through the system. Identifying such bogus blocks is difficult and requires the use of homomorphic hashing functions, which are computationally expensive. This paper presents a practical security scheme for network coding that reduces the cost of verifying blocks on-the-fly while efficiently preventing the propagation of malicious blocks. In our scheme, users not only cooperate to distribute the content, but (well-behaved) users also cooperate to protect themselves against malicious users by informing affected nodes when a malicious block is found. We analyze and study such cooperative security scheme and introduce elegant techniques to prevent DoS attacks. We show that the loss in the efficiency caused by the attackers is limited to the effort the attackers put to corrupt the communication, which is a natural lower bound in the damage of the system.
In IEEE/Infocom Barcelona
Publisher IEEE Communications Society
Copyright © 2007 IEEE. Reprinted from IEEE Communications Society. This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to email@example.com. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.