DDos Attack against Proxy in PRE and PRS

Abstract— In 1998, Blaze, Bleumer, and Strauss proposednew kind of cryptographic primitives called proxy re-encryption (PRE) and proxy re-signature (PRS). In proxy re-encryption, a proxy can transform a ciphertext computedunder Alice’s public key into one that can be opened underBob’s decryption key. In proxy re-signature, a proxy cantransform a signature computed under Alice’s secret keyinto one that can be verified by Bob’s public key. In 2005,Ateniese et al proposed a few new re-encryption schemesand discussed its several potential applications especially inthe secure distributed storage. In 2006, they proposedanother few proxy re-signature schemes and also discussedits several potential applications. They predicated thatproxy re-encryption and proxy re-signature will play animportant role in our life. Since then, researchers aresparked to give new lights to this area. Many excellentschemes have been proposed. In this paper, we introducea new attack- DDos attack against proxy in the proxy re-cryptography. Although this attack can also be implementedagainst other cryptographic primitives, the danger caused byit in proxy re-cryptography seems more serious. We revisitthe current literature, paying attention on their resistingDDos attack ability. We suggest a solution to decline theimpact of DDos attacking. Also we give a new efficient re-encryption scheme which can achieve CCA2 secure basedon Cramer-Shoup encryption scheme and prove its security.We point out this is the most efficient proxy re-encryptionschemes for the proxy which can achieve CCA2 secure inthe literature. At last we give our conclusions with hoping researchers give more attention on this attack.