The Research Of Identity Based Encryption And Leakage Resilient Zero Knowledge

Encryption is a fundamental primitive of the cryptography and it is a basic tool of thesecret communication. With the development of the modern technology, the secretcommunication plays an important role in the people’s life. Meanwhile, to satisfy therequirement of the various applications, a number of encryption schemes which has somespecial properties were brought forward in succession. Such as, the identity based encryption,the attributed based encryption, the full homomorphism encryption and the non committingencryption for which used in secure multi party computation.Our research work in this thesis foucus on the identity based encryption in the standardmodel. The previous id-based encryption schemes proved their security by using the randomoracle model. Though these schemes have high efficiency, the current results shows that therandom oracle model only be a security modle in the ideal condition, the schemes for provingsecurity in the the random oracle model may be not secure in the application. Most currentid-based encryption schemes are using the standard modle to prove its security.We mainly finished the following works in this thesis as follows:1. This work foucus on identity based encryption in the standard model, two identitybased encryption schemes with tight reduction in the standard model to improve the Water’sdentity based encryption scheme are proposed in this work. In the two proposed schemes, theprogrammable hash function and the Composite order bilinear group were adopted. The forceabort in the security proof of Waster’s scheme is removed. The two proposed schemes aretight reduction, and their security is impoved.2. A leakage resilient zero knowledge against fully leakage verifier by using thetrapdoor commitment and non black box simulation is proposed in this work. The problem ofleaking the full secret states of verifier to the prover is solved in this work.3. Based on the result of Goldreich, a counterexample which sequential compositionauxiliary zero knowledge against leakage resilient prover does not hold is proposed in thisthesis. The problem of possibility or impossibility for sequential composition auxiliary zeroknowledge against leakage resilient prover is solved in this thesis. However, a negative resultis obtained in this work.