Constructions And Analysis Of Public Key Encryption With Keyword Search

Public key encryption with keyword search provides the ability that a sever could test whether the ciphertext contains a keyword without decrypting the messages and keywords.This makes up the deficiency of the general encryption and decryption algorithm.In a public key encryption scheme with keyword search,a sender sends the ciphertext to the sever,and a receiver sends the trapdoor of the keyword to the sever.The sever tests the above ciphertext and trapdoor by a adviced algorithm.If the result is "yes",it means successful,i.e.the receiver can search the ciphertext,otherwise not.In all processes of above,the information of messages and keywords will not be leaked.In this paper,we describe an anonymous identity based encryption scheme firstly.Based on this scheme,we give a public key encryption scheme with keyword search on prime order bilinear groups.And this scheme is proved to be indistinguishable of PEKS against chosen keyword attack(IND-PEKS-CPA)under the decisional bilinear Diffie-Hellman(DBDH)assumption and D-Linear assumption in the random oracle model.Compared with other public encryption schemes with keyword search,our scheme has shorter private key and ciphertext and less cost of comunitation.Then,based on the bilinear pairing technology,We propose a decryptable search-able public key encryption scheme with a designated tester which can decrypt out message.This scheme solves the drawback that other public key encryption schemes with keyword search can not restore communication messages.The discrete logarithm difficult problem is used to prove that the scheme is indistinguishable of ciphertext under chosen keyword attack.In addition,this scheme is also proved to be indistin-guishable secure of trapdoor under chosen keyword attack under the computational Diffie-Hellman assumption.Compared with other searchable public key encryption schemes with a designated tester,the proposed scheme is more practical.Lastly,we put the above scheme into practice in the mail service system which guarantees the communication security in daliy operation of mail service system.