File Security using Homomorphic Hashing in Peer to Peer Networks
Nirmit Desai1, Chitesh Tewani2, Karl Elavia3, Omkar Gawde4, Kiran Joshi5

1Nirmit Desai, B.Tech Student, Computer Science & Information Technology Department, VJTI, Mumbai, India.
2Chitesh Tewani, B.Tech Student, Computer Science & Information Technology Department, VJTI, Mumbai, India.
3Karl Elavia, B.Tech Student, Computer Science & Information Technology Department, VJTI, Mumbai, India.
4Omkar Gawde, B.Tech Student, Computer Science & Information Technology Department, VJTI, Mumbai, India.
5Kiran Joshi, Assistant Professor, Computer Science & Information Technology Department, VJTI, Mumbai, India.
Manuscript received on September 15, 2014. | Revised Manuscript received on September 22, 2014. | Manuscript published on September 25, 2014. | PP: 39-44 | Volume-2 Issue-11, September 2014. | Retrieval Number: K08070921114/2014©BEIESP

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© The Authors. Published By: Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: This paper focuses primarily with homomorphic hashing and the quality of peer-to-peer content distribution. Some systems using simple block-by-block downloading can verify blocks with traditional cryptographic signatures and hashes, but these techniques do not apply well to more elegant systems that use rate less erasure codes for efficient multicast transfers. This paper presents a practical scheme, based on homomorphic hashing, that enables a downloader to perform onthe-fly verification of erasure-encoded blocks. Peer-to-peer content distribution networks can suffer from malicious participants that intentionally corrupt content. Traditional systems verify blocks with traditional cryptographic signatures and hashes. However, these techniques do not apply well to more elegant schemes that use network coding techniques for efficient content distribution. Problems that occur with these techniques are that peers have no way of knowing which block was bad if a piece they download fails hash check, and if they’re streaming data they can’t display it until a full piece is downloaded for hash verification purposes. Also there is a huge waste of bandwidth when a piece does not pass hash check, in fact, the peer must discard all the blocks (even all the correct ones) and then redownload all the blocks within the piece. It is better to discard only bad blocks, and re-download only them which will save bandwidth. Identifying such bogus blocks is difficult and requires the use of homomorphic hashing functions. This paper deals with reducing the bogus blocks by implementing homomorphic hashes on the blocks and using Luby Transform Codes on peer to peer networks.
Keywords: Homomorphic Hashing, Peer-to-peer (P2P), Luby Transform Codes (LT codes), Erasure Codes, File security