Research On Several Signcryption Schemes

The information technology is developing fastly.Many advantages are given to our life by the development of the information technology.But at the same time,more and more problems are exposed in the information security.We are aware of the importance of the Information security.As we all know,the cryptography is the core of the Information security.The cryptosystem based on the traditional problem is used widely,such as the usage in the field of military,daily life,E-commerce,e-government ect.But the traditional cryptosystem itself has limitations according to existing researches,thus,we do the research on ID-based server-aided verification signcryption and ID-based Signcryption schemes using the Chebyshev chaotic maps.To decrease computation of receiver and promote verification efficiency,a feasible way is thought of server-aided verification which means giving some complex computation to an extra server.As a new cryptosystem,researches on chotic cryptography are valuable.Chebyshev chaotic maps has advantages like simple computation and excellent attributes,so it is the most common mathematics method in chaotic cryptography.ID-based Signcryption means the only requirement of identity messages of participants as public key to avoid the certificates in traditional cryptosystem.Usually,the sender encrypts message with receiver's public key,and does the signature with his/her own secret key.Efficiency of this way is higher than that of traditional “signature-then-encryption” and “encryption-then-signature”.The content of this paper inclulds following two parts:(1)In order to improve the efficiency of the existing identity-based signcryption scheme,this paper takes the disadvantage,small computation capabilities,of low-power devices into consideration,and proposes a new efficient ID-based server-aided verification scheme using the bilinear pairings and both the combination of ID-based signcryption and the thought of server-aided verification.A server-aided verification signcryption means that some complex computation for verification of a signcryption is carried out by a server.Compared with the existing ID-based signcryption scheme,the scheme had high efficiency.And it also proved the scheme's security of unforgeability and confidentiality in the random oracle model while assuming the hardness of DBDH problem and CDH problem.(2)We use the Chebyshev chaotic maps as mathematics method and propose three novel Identity-based signcryption schemes.There,we apply the designing thought of RSA to the first scheme.In the second scheme,we flexibly transmit the message of sender and receiver.The last scheme obtain less computation and shorter ciphertext.The difficulty of chaos-based discrete logarithm(CDL)problem and the intractability assumption of chaos-based decisional Diffie-Hellman(CDDH)problem lay the foundation of the security of proposed ECM-IBSC schemes.