Enabling Re-encryption of Hierarchical Verifiable Permutation Scheme for Bittorrent Chunk Exchanges

Peer-to-peer networks such as BitTorrent swarms have gained popularity on Internet. One of the fundamental underlying mechanisms is to foster and enforce peer cooperativeness. As for fairly exchanging Bit Torrent chunks, peers may resort to encrypted chunk exchanges yet at the cost of delayed availability of plain chunks. In response, this paper presents a chunk encryption scheme for exchanging chunks between Bit Torrent peers. This scheme uses only permutation-based operations. Further, two layers of permutation are conducted in order to hide more chunk information. As counts of zero and one bits are unchanged, the verifiable characteristic can be achieved. Finally, re-encryption capability is introduced for mitigating delayed availability problems that occur under encrypted chunk exchanges.