An Efficient Public Verifiable Identity-based Signcryption Scheme

As doing many activities in public Internet becomes more and more popular, such as sending email, paying, auction and signing contract, people demands the data's transmission be more and more secure in public network. Using cipher technology is a good method to ensure the safety of the public network communication. Encryption and digital signature are two basic techniques to guarantee the communication safety. In order to avoid forgery and ensure confidentiality, traditionally, we should combine the encryption algorithm and the digital signature algorithm in the form of "encryption and signature ".But there are three shortages:low efficiency, many keys, many potential safety problems. In 1997, Zheng first proposed the concept of signcryption which is a cryptographic primitive that combines both the functions of digital signature and public key encryption in a logical single step, at lower computational costs and communication overheads than traditional "composing signature and encryption". After then, people proposed many algorithms based on different hard problems.Main work in this paper is summarized as following:(1) the overviews of the identity-based signcryption, the foundation of cryptography and related mathematical knowledge. The background of the identity-based signcryption including the signcryption, the identity-based cryptosystem,and the identity-based signcryption. The foundation of cryptography mainly includes the hash function and provable security theory. Related mathematics knowledge mainly includes the definition of bilinear pairing and some hard problems.(2) Introduce the definition of identity-based signcryption and the security model in random oracle model.(3) Introduce four typical identity-based signcryption schemes, and analysis their characteristics and deficiencies.(4) Take the advantages of four typical schemes mentioned before,we construct a new identity-based signcryption scheme from elliptic curve bilinear. The new scheme is confidential, unforgeable, non-repudiation, public verifiable and forward secure. The new scheme is more efficient and more secure than other. We will proof the security in random oracle model.