Analysis And Improvement Of A Certificateless Signcryption Scheme

Public Key Cryptography plays an important role in the field of information security, but there is a very important issue in public key cryptography is how to guarantee the authenticity of public keys.Certificateless public key cryptography not only guarantee the authenticity of public keys, as a trusted authentication way to convince people that the relationship between a public key and private key with the user who have a private key, but also compared with the traditional Public Key Cryptography based on identity,it can overcome the key escrow problem inherent, reached higher security.Recently, based on certificateless cryptosystem,some researchers proposed Certificateless signcryption scheme.The signing of efficiency is much higher than the method of "The first signature encryption", so it is very suitable for Safe transmission of large amounts of data, at the same time,when using larger security parameters, the safety performance of signcryption scheme will be better, because the security parameter to save cost and the length is proportional to.In this paper, from two aspects of signcryption scheme research on certificateless: one is the security analysis of the existing schemes, the two is the improvement of the existing scheme. The main contents are as follows:First of all, introduced the preliminary data of the digital signature preliminaries which related to certificate signcryption scheme. Such as:Identity-based cryptosystem and Certificateless public key cryptosystem. Because the signcryption mechanism is Melting The Certificateless public key cryptosystem and Public-key encryption scheme as a whole, the paper will mainly introduces the digital signature technique.Secondly, after researching the scheme of Fan AiJing and analyzesing its security,we found thatthe Signcryption and verification process has not resulted in plaintext ciphertext,so it lead to plaintext can be counterfeited and the attacker can according to the verification algorithm to construct a false signature algorithm, replacing the original algorithm and other unsafe factors, pointed out that Fan Aijing put forward certificateless signcryption scheme is not satisfy unforgeability, it is unsafe, but also cannot be applied to the actual.Finally, improving on Fan Ai Jing’s project of "No certificate of signcryption schemes" proposed a certificateless signcryption scheme which have been shown to be safe.