Design And Security Analysis Of Signcryption System

In traditional public key cryptography, in order to ensure the confidentiality andauthenticity of a message, usually adopt signature-then-encryption approach.Signcryption can achieve signature and encryption functions.Compared signcryptionwith signature-then-encryption,we can find that signcrytion is much more efficientthan signature-then-encryption.Public-key cryptosystems can be divided into threecategories. Combining signcryption and these cryptosystems, we can getcertificate-based signcryption system, identity-based signcryption system andcertificateless signcryption system.Using combination of signcryption and some othercryptography technologies, we can get a new signcryption scheme with specialproperty.In practical application environment， the event of key-exposure often causessecurity problems.Key insulation is used to solve the problem of the exposure ofsecret keys. Key-insulation model ensures that if the private key of a period of timedisclosed, other time periods encryption or signature is still secure.In this paper,we focus on the signcryption which is builded in identity-basedpublic key cryptosystems. After analyzing some typical combination of signcryptionand some key-insulation technology， we propose an identity-based key-insulationsigncryption scheme.We propose the common components and the specific design ofour algorithm. We also prove its security in the random oracle.Wireless sensor networks (WSNs) are ad hoc networks which usually consist ofa large number of tiny sensor nodes with limited resources and one or more basestations. Usually, sensor nodes consist of a processing unit with limited computationalpower and limited capacity.Authentication is an important security requirement forwireless sensor networks. Digital signature plays a crucial role to provide integrity,authentication and non-repudiation of data. In this thesis, we propose a practicalidentity-based online/offline signature scheme for wireless sensor networks. Ourscheme splits the signature generation into two phases: offline phase and online phase.In the offline part, most heavy computations are done without the knowledge of amessage. In the online stage, only light computations are done when the message isknown.We propose the common components and the specific design of our algorithm.We also prove its security in the random oracle. Compared with otherschmes, we can find that our schme has the lowest computational cost.