Research Of The Identity-based Encryption And Signature

With rapid development of computer network, E-government and E-commerce, informationsecurity has become more and more important. Information encryption and digital signature whichcan provide the information confidentiality, authentication, non-repudiation and integrity, are thecrucial techniques in information security and play an important part in military affairs, ID-basedcryptosystems which can simplifies key management process in traditional public-keycryptosystem, is becoming the center of the stage. The study of digital signature has been from thetraditional digital signature technology to particular digital signature which can satisfy differentcircumstances. Signcryption can achieve both the information confidentiality and authentication.In this thesis, the author discusses Identity-Based encryption and digital signature. The work ofthis dissertation is mainly on the generic models and security definitions of encryption and digitalsignature, ID-based aggregate signature and ID-based signcryption. An aggregate signature schemeis a digital signature that given n signatures on n distinct messages from n distinct users, it ispossible to aggregate all these signatures into a single signature. Signcryption can achieve both thesignature and encryption function in a logic step and is with the cost lower than common way "firstsignature and thenencryption" or "first encryption and thensignature".The main contributions are as follows.1.The thesis analyzes two Identity-Based aggregate signature schemes and proves they areinsecure .Based on the given schemes the author proposes a new ID-based aggregate signaturescheme based on the bilinear pairings. The author proves that the new aggregate signature scheme issecure against existential forgery under adaptively chosen message and Identity attack in the randomoracle model, assuming that the Computational Diffie-Hellman problem is hard to solve.2.The author gives a novel identity-based signcryption from bilinear pairings and the securityis based on Diffie-Hellman problems. In this thesis, the author proves the novel id-basedsigncryption security which include: confidentiality, unforgeability , public provability,authentication, especially the prove of forward security. Use PBC library in linux operating system,this dissertation gives each step costs CPU time-consuming in the ID-based signcryption, at thesame time, in the same circumstance, gives the main arithmetic costs CPU time-consuming based onelliptic curve.