Research On Code-based Special Digital Signature And Hybrid Encryption Algorithm

Cyberspace Security is an important guarantee for the development of “Internet+” information technology.With the rapid development of quantum communication research,today's network security solutions based on traditional public key cryptography are facing the great impact and security challenges.The security of most public key encryption schemes(such as RSA encryption,El Gamal encryption,etc.)are based on the traditional number theory hypothesis,these schemes can be broken by large and stable quantum computers.So,it is necessary to explore cryptographic schemes that can resist quantum computer attacks.Since the code-based cryptosystem has high security and good implementation efficiency,suitable for a large number of devices with weak computing power.It has become one of the most potential post quantum attack cryptosystems in the future,and has attracted the attention of many experts and scholars.The code-based cryptosystem is mainly constructed based on the security assumption of syndrome decoding problem and its expansion.After decades of cryptanalysis,it can be applied to the construction of public key encryption,digital signature and key encapsulation algorithms.However,the code-based cryptosystem still has many problems,the common problem of relevant schemes is that the key size is too large,the implementation efficiency is low,and does not meet the practical needs.In addition,the research of code-based digital signature algorithm is still immature,there are only a few relevant research schemes,and lack of efficient and provably secure signature algorithm.In view of the above problems,this paper focuses on the research about code-based digital signature algorithm with special attributes and hybrid encryption algorithm,and tries to use structure code with better performance to improve the security and implementation efficiency of our schemes.Specifically,the main contributions of this thesis are summarized as follows:(1)Construct the first code-based group signature with verifier-local revocation.In order to make the group signature algorithm more practical,this paper proposes an efficient code-based group signature scheme supporting member revocation.In view of the immature development of code-based signature,our construct is different from the traditional “signature-encryption-proof” paradigm,and does not depend on an encryption scheme and signature scheme.Concretely,we first introduce a new code-based Stern-like interactive zero-knowledge protocol with member revocation mechanism,and combining other related technologies such as one-time pad,bonsai tree structure to complete the construction of this scheme.Moreover,we give the security analysis of correctness,selfless-anonymous and traceability,and reduce its security to the classical syndrome decoding problem.Finally,we employ the binary Goppa code embedded with its efficiency and security analysis.(2)Present an efficient code-based blind signature scheme with local restart.We propose an efficient code-based blind signature scheme under the random ora-cle model.Different from Blazy et al.'s scheme(the first code-based blind signa-ture,and the only one so far),we present a simple construction and avoid the global restart problem in the interaction between a signer S and a user U.Technically,we mainly use a powerful tool one-way trapdoor preimage sampleable function(PSF)based on(U,U + V)-code,a three-round interaction zero-knowledge protocol be-tween a signer S and a user U.By using the signer's “trapdoor” to execute some efficient reject sampling algorithms in the signature process,the ”global restart” in the whole protocol is upgraded to the “local restart” of the client,which greatly im-proves the implementation efficiency of the scheme.Finally,we give the detailed analysis of its correctness,blindness and one-more unforgeability.Its security reduced to two difficult assumptions: the distinguishing a permuted generalized(U,U + V)-code and the decoding one out of many problem.(3)Propose a IND-CCA secure hybrid encryption in the multi-instance set-ting.In order to improve the practicability of code-based public key encryption algorithm,we introduce a direct construction of code-based multi-instance hybrid encryption scheme under the oracle model,and achieves the IND-CCA security.The security reduced to the classical syndrome decoding problem,which is a clas-sical NPC problem.Therefore,we design the KEM and DEM algorithms of IND-CCA security under multi-user settings,and combine the two modules to obtain a hybrid encryption framework that can deal with multi-user and multi challenge attacks at the same time.Finally,we give an instantiation of our scheme based on QC-LDPC code.The results show that our scheme achieves small private key size and only consumes addition and multiplication operations over finite field.In conclusion,the research focuses on the design and research of code-based post quantum cryptography from the perspective of provable security theory and efficiency.The proposed schemes promote the theoretical research and help to speed up the imple-mentation process of Coding based cryptosystem.