Research On Proxy Re-encryption Based On Fuzzy Key Words Search

Since public-key cryptography has been proposed, the cryptography scholars have proposed anumber of different public key encryption schemes and gave security proof for the program. Relativeto the symmetric encryption, public key has higher encryption security and higher complexity. FuzzyIdentity-Based encryption scheme which used key words instead of identity formation is on the basisof the IBE, Amit Sahai and Brent Waters created strict construction of the scheme and proved its CCAsecurity.First, we used the PBC(Pairing-Based Cryptography) library to programming the fuzzyidentity-based encryption scheme. The paper gives a detailed exposition for the program’s technicalrealization. Through the realization of the experiment, we deepened the understanding of fuzzy IBE.At the same time, we also found a shortage of it, its keywords displayed by plain text in the ciphertext,so the attackers can modify keyword easily. This kind of behavior will cause the decryption can’tdecrypt the ciphertext, this paper proposed a new encryption scheme based on searching key wordsencryption. The main idea is the service provider encrypt message m with a set k of key words, weset a threshold limit value as error-tolerance, if other users decrypt a ciphertext by a set k ’, if andonly if the set k and k ’are close to each other as measured by the “set overlap” distance metric.Additionally, we provide safety analysis and probabilistic analysis for this program.Proxy re-encryption algorithm used to encrypting e-mail system, distributed file system and otherfields, the main idea is that the server converts the ciphertext which is encrypted by user A’s publickey to ciphertext which is encrypted by user B’s public key. We construct proxy re-encryption withkeyword searching function based on the traditional proxy re-encryption that the proxy server canconvert ciphertext by checking whether the keywords which include in the ciphertext meet thecondition, so the server will have the selective conversion of a part of the users ciphertext, instead ofconverting his all ciphertext.