Provable Efficient Certificateless Group Key Exchange Protocol

Certificateless public key cryptography （CL-PKC） avoids the inherent escrow of identity-based cryptography and does not require certificates to guarantee the authenticity of public keys. Based on CL-PKC, we present an efficient constant-round group key exchange protocol, which is provably secure under the intractability of computation Diffie-Hellman problem. Our protocol is a contributory key exchange with perfect forward secrecy and has only two communication rounds. So it is more efficient than other protocols. Moreover, our protocol provides a method to design efficient constant-round group key exchange protocols and most secret sharing schemes could be adopted to construct our protocol.

LINEAR PROVABLE SECURITY FOR A CLASS OF UNBALANCED FEISTEL NETWORK

A structure iterated by the unbalanced Feistel networks is introduced. It is showed that this structure is provable resistant against linear attack. The main result of this paper is that the upper bound of r-round （r≥2m） linear hull probabilities are bounded by q^2 when around function F is bijective and the maximal linear hull probabilities of round function F is q. Application of this structure to block cipher designs brings out the provable security against linear attack with the upper bounds of probabilities.

An Efficient Provable Secure ID-Based Proxy Signature Scheme Based on CDH Assumption

Identity-based proxy signature enables an entity to delegate its signing rights to another entity in identity-based cryptosystem settings. However, few existing scheme has been proved secure in a formalized model, or acquired optimized performance. To achieve the goals of both proven security and high efficiency, this paper proposed an efficient identity-based proxy signature scheme. The scheme is constructed from bilinear pairing and proved secure in the random oracle model, using the oracle replay attack technique introduced by Pointehval and Stern. The analysis shows that the scheme needs less computation costs and has a shorter signature than the other schemes.

A Novel Provable Data Possession Scheme Based on Geographic Location Attribute

Increment of mobile cloud video motivates mobile users to utilize cloud storage service to address their demands, cloud storage provider always furnish a location-independent platform for managing user＇s data. However, mobile users wonder if their cloud video data leakage or dynamic migration to illegal service providers. In this paper, we design a novel provable data possession protocol based on data geographic location attribute, which allows data owner to auditing the integrity of their video data, which put forward an ideal choice for remote data possession checking in the mobile cloud storage. In our proposed scheme, we check out whether the video data dynamic migrate to an unspecified location （such as： overseas） by adding data geographic location attribute tag into provable data possession protocol. Moreover, we make sure the security of our proposed scheme under the Computational Diffic-Hellman assumption. The analysis and experiment results demonstrate that our proposed scheme is provably secure and efficient.

Blockchain-Based Light-Weighted Provable Data Possession for Low Performance Devices

Provable Data Possession(PDP)schemes have long been proposed to solve problem of how to check the integrity of data stored in cloud service without downloading.However,with the emerging of network consisting of low performance devices such as Internet of Things,we find that there are still two obstacles for applying PDP schemes.The first one is the heavy computation overhead in generating tags for data blocks,which is essential for setting up any PDP scheme.The other one is how to resist collusion attacks from third party auditors with any possible entities participating the auditing.In this paper,we propose a novel blockchain-based light-weighted PDP scheme for low performance devices,with an instance deployed on a cloud server.We design a secure outsourced tag generating method for low performance devices,which enables a kind of“hash-sign-switch”two-phase tag computing.With this method,users with low performance devices can employ third party auditors to compute modular exponential operations that accounts for the largest portion of computation overhead in tag generation,without leaking their data content.Chaincodes in blockchain network ensure the correctness of such outsourcing and prevent collusion attacks.The security analysis and performance evaluation prove that our scheme is both secure and efficient.

Provable Security of ID-Based Proxy Multi-Signature Schemes

In the last couple of years, D-based cryptography has got fruitful achievements. Proxy multi-signature allows a designated person, called a proxy signer, to sign on behalf of two or more original signers. In this paper, we present a general security model for ID-based proxy multi-signature （ID-PMS） schemes. Then, we show how to construct a secure ID-PMS scheme from a secure ID-based signature scheme, and prove that the security of the construction can be reduced to the security of the original ID-based signature scheme.

Reducing Computational and Communication Complexity for Dynamic Provable Data Possession

Nowadays, an increasing number of persons choose to outsource their computing demands and storage demands to the Cloud. In order to ensure the integrity of the data in the untrusted Cloud, especially the dynamic files which can be updated online, we propose an improved dynamic provable data possession model. We use some homomorphic tags to verify the integrity of the file and use some hash values generated by some secret values and tags to prevent replay attack and forgery attack. Compared with previous works, our proposal reduces the computational and communication complexity from O(logn) to O(1). We did some experiments to ensure this improvement and extended the model to file sharing situation.

Sec-Auditor:A Blockchain-Based Data Auditing Solution for Ensuring Integrity and Semantic Correctness

Currently,there is a growing trend among users to store their data in the cloud.However,the cloud is vulnerable to persistent data corruption risks arising from equipment failures and hacker attacks.Additionally,when users perform file operations,the semantic integrity of the data can be compromised.Ensuring both data integrity and semantic correctness has become a critical issue that requires attention.We introduce a pioneering solution called Sec-Auditor,the first of its kind with the ability to verify data integrity and semantic correctness simultaneously,while maintaining a constant communication cost independent of the audited data volume.Sec-Auditor also supports public auditing,enabling anyone with access to public information to conduct data audits.This feature makes Sec-Auditor highly adaptable to open data environments,such as the cloud.In Sec-Auditor,users are assigned specific rules that are utilized to verify the accuracy of data semantic.Furthermore,users are given the flexibility to update their own rules as needed.We conduct in-depth analyses of the correctness and security of Sec-Auditor.We also compare several important security attributes with existing schemes,demonstrating the superior properties of Sec-Auditor.Evaluation results demonstrate that even for time-consuming file upload operations,our solution is more efficient than the comparison one.

An Efficient and Provably Secure SM2 Key-Insulated Signature Scheme for Industrial Internet of Things

With the continuous expansion of the Industrial Internet of Things(IIoT),more andmore organisations are placing large amounts of data in the cloud to reduce overheads.However,the channel between cloud servers and smart equipment is not trustworthy,so the issue of data authenticity needs to be addressed.The SM2 digital signature algorithm can provide an authentication mechanism for data to solve such problems.Unfortunately,it still suffers from the problem of key exposure.In order to address this concern,this study first introduces a key-insulated scheme,SM2-KI-SIGN,based on the SM2 algorithm.This scheme boasts strong key insulation and secure keyupdates.Our scheme uses the elliptic curve algorithm,which is not only more efficient but also more suitable for IIoT-cloud environments.Finally,the security proof of SM2-KI-SIGN is given under the Elliptic Curve Discrete Logarithm(ECDL)assumption in the random oracle.

A provable-secure and practical two-party distributed signing protocol for SM2 signature algorithm

Mobile devices are widely used for data access,communications and storage.However,storing a private key for signature and other cryptographic usage on a single mobile device can be challenging,due to its computational limitations.Thus,a number of(t,n)threshold secret sharing schemes designed to minimize private key from leakage have been proposed in the literature.However,existing schemes generally suffer from key reconstruction attack.In this paper,we propose an efficient and secure two-party distributed signing protocol for the SM2 signature algorithm.The latter has been mandated by the Chinese government for all electronic commerce applications.The proposed protocol separates the private key to storage on two devices and can generate a valid signature without the need to reconstruct the entire private key.We prove that our protocol is secure under nonstandard assumption.Then,we implement our protocol using MIRACL Cryptographic SDK to demonstrate that the protocol can be deployed in practice to prevent key disclosure.

A novel pairing-free certificateless authenticated key agreement protocol with provable security

Recently, He et al. （Computers and Mathematics with Applications, 2012） proposed an efficient pairing-free certificateless authenticated key agreement （CL-AKA） protocol and claimed their protocol was provably secure in the extended Canetti-Krawczyk （eCK） model. By giving concrete attacks, we indicate that their protocol is not secure in the eCK model. We propose an improved protocol and show our improvement is secure in the eCK model under the gap DiffieHellman （GDH） assumption. Furthermore, the proposed protocol is very efficient.

Towards Comprehensive Provable Data Possession in Cloud Computing

To check the remote data integrity in cloud computing,we have proposed an efficient and full data dynamic provable data possession（PDP） scheme that uses a SN（serial number）-BN（block number） table to support data block update.In this article,we first analyze and test its performance in detail.The result shows that our scheme is efficient with low computation,storage,and communication costs.Then,we discuss how to extend the dynamic scheme to support other features,including public auditability,privacy preservation,fairness,and multiple-replica checking.After being extended,a comprehensive PDP scheme that has high efficiency and satisfies all main requirements is provided.

Research on a provable security RFID authentication protocol based on Hash function

Research on existing radio frequency identification（RFID） authentication protocols security risks, poor performance and other problems, a RFID security authentication protocol based on dynamic identification（ID） and Key value renewal is proposed. Meanwhile, the security problems based on Hash function RFID security authentication protocol in recent years have been also sorted and analyzed. Then a security model to design and analyze RFID protocols is built. By using the computational complexity, its correctness and security have been proved. Compared with the safety performance, storage overhead, computational overhead and other aspects of other protocols, the protocol for RFID has more efficient performance and ability to withstand various attacks. And the C# programming language is used to simulate the authentication process on the visual studio platform, which verifies the feasibility of the protocol.

Blockchain-based Privacy-Preserving Group Data Auditing with Secure User Revocation

Progress in cloud computing makes group data sharing in outsourced storage a reality.People join in group and share data with each other,making team work more convenient.This new application scenario also faces data security threats,even more complex.When a user quit its group,remaining data block signatures must be re-signed to ensure security.Some researchers noticed this problem and proposed a few works to relieve computing overhead on user side.However,considering the privacy and security need of group auditing,there still lacks a comprehensive solution to implement secure group user revocation,supporting identity privacy preserving and collusion attack resistance.Aiming at this target,we construct a concrete scheme based on ring signature and smart contracts.We introduce linkable ring signature to build a kind of novel meta data for integrity proof enabling anonymous verification.And the new meta data supports secure revocation.Meanwhile,smart contracts are using for resisting possible collusion attack and malicious re-signing computation.Under the combined effectiveness of both signature method and blockchain smart contracts,our proposal supports reliable user revocation and signature re-signing,without revealing any user identity in the whole process.Security and performance analysis compared with previous works prove that the proposed scheme is feasible and efficient.

A Linear Homomorphic Proxy Signature Scheme Based on Blockchain for Internet of Things

The mushroom growth of IoT has been accompanied by the generation of massive amounts of data.Subject to the limited storage and computing capabilities ofmost IoT devices,a growing number of institutions and organizations outsource their data computing tasks to cloud servers to obtain efficient and accurate computation while avoiding the cost of local data computing.One of the most important challenges facing outsourcing computing is how to ensure the correctness of computation results.Linearly homomorphic proxy signature(LHPS)is a desirable solution to ensure the reliability of outsourcing computing in the case of authorized signing right.Blockchain has the characteristics of tamper-proof and traceability,and is a new technology to solve data security.However,as far as we know,constructions of LHPS have been few and far between.In addition,the existing LHPS scheme does not focus on homomorphic unforgeability and does not use blockchain technology.Herein,we improve the security model of the LHPS scheme,and the usual existential forgery and homomorphic existential forgery of two types of adversaries are considered.Under the new model,we present a blockchain-based LHPS scheme.The security analysis shows that under the adaptive chosen message attack,the unforgeability of the proposed scheme can be reduced to the CDH hard assumption,while achieving the usual and homomorphic existential unforgeability.Moreover,comparedwith the previous LHPS scheme,the performance analysis shows that our scheme has the same key size and comparable computational overhead,but has higher security.

Blockchain-Based Privacy-Preserving Public Auditing for Group Shared Data

Cloud storage has been widely used to team work or cooperation devel-opment.Data owners set up groups,generating and uploading their data to cloud storage,while other users in the groups download and make use of it,which is called group data sharing.As all kinds of cloud service,data group sharing also suffers from hardware/software failures and human errors.Provable Data Posses-sion(PDP)schemes are proposed to check the integrity of data stored in cloud without downloading.However,there are still some unmet needs lying in auditing group shared data.Researchers propose four issues necessary for a secure group shared data auditing:public verification,identity privacy,collusion attack resis-tance and traceability.However,none of the published work has succeeded in achieving all of these properties so far.In this paper,we propose a novel block-chain-based ring signature PDP scheme for group shared data,with an instance deployed on a cloud server.We design a linkable ring signature method called Linkable Homomorphic Authenticable Ring Signature(LHARS)to implement public anonymous auditing for group data.We also build smart contracts to resist collusion attack in group auditing.The security analysis and performance evalua-tion prove that our scheme is both secure and efficient.

Certificateless Public Key Encryption with Keyword Search

Public Key Encryption with Keyword Search （PEKS）, an indispensable part of searchable encryption, is stock-in- trade for both protecting data and providing operability of encrypted data. So far most of PEKS schemes have been established on Identity-Based Cryptography （IBC） with key escrow problem inherently. Such problem severely restricts the promotion of IBC-based Public Key Infrastructure including PEKS component. Hence, Certificateless Public Key Cryptography （CLPKC） is efficient to remove such problem. CLPKC is introduced into PEKS, and a general model of Certificateless PEKS （CLPEKS） is formalized. In addition, a practical CLPEKS scheme is constructed with security and efficiency analyses. The proposal is secure channel free, and semantically secure against adaptive chosen keyword attack and keyword guessing attack. To illustrate the superiority, massive experiments are conducted on Enron Email dataset which is famous in information retrieval field. Compared with existed constructions, CLPEKS improves the efficiency in theory and removes the key escrow problem.

Efficient and Provably Secure Multi-Recipient Signcryption from Bilinear Pairings

Signcryption is a cryptographic primitive that performs signature and encryption simultaneously, at lower computational costs and communication overheads than the signature-then- encryption approach. In this paper, we propose an efficient multi-recipient signcryption scheme based on the bilinear pairings, which broadcasts a message to multiple users in a secure and authenticated manner. We prove its semantic security and unforgeability under the Gap Diffie-Hellman problem assumption in the random oracle model. The proposed scheme is more efficient than re-signcrypting a message n times using a signcryption scheme in terms of computational costs and communication overheads.

Secure and efficient multi-message and multi-receiver ID-based signcryption for rekeying in ad hoc networks

In this paper, the security technology of ad hoc networks is studied.To improve the previous multi-receiver signcryption schemes, an ID-based multi-message and multi-receiver signcryption scheme for rekeying in ad hoc networks is proposed.In this scheme, a sender can simultaneously signcrypt n messeges for n receivers, and a receiver can unsigncrypt the ciphertext to get his message with his own private key.An analysis of this scheme indicates that it achieves authenticity and confidentiality in the random oracle model while being of lower computation and communication overhead.Finally, for the application of our scheme in ad hoc, a threshold key updating protocol for ad hoc networks is given.

A Formal Model for the Security of Proxy Signature Schemes

This paper provides theoretical foundations for the secure proxy signatureprimitive. We pres-enta formal model for the security of proxy signature schemes, which defines thecapabilities of the adversary and the security goals to capture which mean for a prox-ysignaturescheme to be secure. Then, we present an example of proxy signature scheme that can be proven securein the standard model.