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Based on Gentry’ s identity based encryption, an identity based proxy re-signature scheme is proposed that is existentially unforgeable in the standard model under the q-SDH (Strong Diffie-Hellman) assumption. Comparison with all previous proxy re-signature schemes, the proposed scheme has a tight security reduction and very compact public(More)
Peer-to-Peer (P2P) content distribution networks such as BitTorrent swarms, are very popular on Internet. These networks rely on reciprocative chunk contribution of participating peers. However, such reciprocation induces the free-riding behavior, where peers receive chunks from other peers and do not upload chunks in return. It is shown in the literature(More)
BitTorrent-like networks are prevailing on Internet, facilitating quick distribution of media files to large numbers of users via aggregating upload bandwidth at the user side. Their successes lie in initial optimistic blocks and active reciprocation on all established connections. However, some misbehaving peers may exploit or sabotage such premises,(More)
In the last of years, many strong designated verifier signature schemes have been proposed. However, most of existing designated verifier proxy signature schemes are only secure in the random oracle which has suffered a lot of criticism. Therefore, secure and strong designated verifier signature in the standard model has attracted much interesting. In this(More)
Recently, Au et al. proposed a hierarchical identity-based signature scheme and Hu-Huang proposed a proxy key generation protocol. Based on the both schemes, we present a novel identity-based proxy signature scheme. The proposed scheme is provablly secure in the standard model and its security can be reduced to the hardness assumption of the g-strong(More)
The known construction of an identity-based blind signature scheme that is secure in the standard model is based on a generic approach which attaches a certificate to an ordinary (i.e. non-identity-based) blind signature scheme, and thus the identity-based blind signature scheme constructed by this method is inefficient and has long signature size. In this(More)
BitTorrent-like networks have attracted many Internet peers to cooperatively download media files of large sizes. Yet some selfish peers intentionally constrain their upload bandwidth, exhibiting the free-riding behavior. In response, cipherblock exchange protocols among participating peers have been proposed. The resultant cipherblocks induce big latency(More)