摘要：hosen ciphertext security (CCA security)hosen ciphertextsecurity (CCA security)C is now a widely acceptednecessary security notion for public key encryption. CCAsecure public verifiable public key encryption has manyapplications such as threshold public key encryption andproxy re-encryption etc. Furthermore, these years “randomoracle model” has seen risen criticize by many cryptographers.Hence, researchers give great effort to pursuepublic key public key encryption with publicly verifiability inthe standard model. However, all the existing CCA securepublicly verifiable public key encryption in the standardmodel relies on costly bilinear pairing. In this paper, basedon Hanaoka and Kurosawa’s efficient CCA secure public keyencryption under Computational Diffle-Hellman assumptionproposed in Asiacrypt’08 and the famous Cramer-Shoupencryption scheme, we try to construct a CCA securepublic verifiable public key encryption without pairing inthe standard model. As a result of its application, weachieve a CCA secure public verifiable threshold public keyencryption without pairing in the standard model, a CCAsecure unidirectional proxy re-encryption without pairingin the standard model.
关键词：Public verifiable public key encryption;CCAsecurity;without Pairings;without Random Oracle.
