Self-Organized Public-Key Management for Mobile Ad Hoc Networks Based on a Bidirectional Trust Model

In traditional networks , the authentication is performed by certificate authoritys（CA）,which can＇t be built in distributed mobile Ad Hoc Networks however. In this pa per, we propose a fully self-organized public key management based on bidirectional trust model without any centralized authority that allows users to generate their public-private key pairs, to issue certificates, and the trust relation spreads rationally according to the truly human relations. In contrast with the traditional self-organized public-key management, the average certificates paths get more short, the authentication passing rate gets more high and the most important is that the bidirectional trust based model satisfys the trust re quirement of hosts better.

Blockchain-Based Key Management Scheme Using Rational Secret Sharing

Traditional blockchain key management schemes store private keys in the same location,which can easily lead to security issues such as a single point of failure.Therefore,decentralized threshold key management schemes have become a research focus for blockchain private key protection.The security of private keys for blockchain user wallet is highly related to user identity authentication and digital asset security.The threshold blockchain private key management schemes based on verifiable secret sharing have made some progress,but these schemes do not consider participants’self-interested behavior,and require trusted nodes to keep private key fragments,resulting in a narrow application scope and low deployment efficiency,which cannot meet the needs of personal wallet private key escrow and recovery in public blockchains.We design a private key management scheme based on rational secret sharing that considers the self-interest of participants in secret sharing protocols,and constrains the behavior of rational participants through reasonable mechanism design,making it more suitable in distributed scenarios such as the public blockchain.The proposed scheme achieves the escrow and recovery of personal wallet private keys without the participation of trusted nodes,and simulate its implementation on smart contracts.Compared to other existing threshold wallet solutions and keymanagement schemes based on password-protected secret sharing(PPSS),the proposed scheme has a wide range of applications,verifiable private key recovery,low communication overhead,higher computational efficiency when users perform one-time multi-key escrow,no need for trusted nodes,and personal rational constraints and anti-collusion attack capabilities.

An Assessment of Procurement Risks Management Systems in the Public Sector

Risk management in public procurement is a critical aspect that needs to be addressed in the public sector.Several studies have been conducted to understand the challenges and factors influencing risk management in public procurement.These studies have explored the importance of risk management principles,the role of political influence,and the need for effective risk assessment and anticipation.The research has also highlighted the need for specific risk management mechanisms and tools to be implemented in public procurement processes.Risk management reforms in the public sector are essential but often circumvented due to assorted reasons,such as political influence and the emergence of new risks.The research investigation employs a quantitative research design.A total of 380 questionnaires were recovered from respondents.The study showed that the public sector has a procurement risk management system that is effective,but there may be some areas for improvement in the prequalification process,onboarding process,and support provided to newly onboarded suppliers.Additionally,the public sector used some strategies to mitigate and control contract risks during the procurement process,but there were some areas for improvement in the review and lessons learned process,risk mitigation measures,contract monitoring and performance evaluation mechanisms,and communication and documentation process.Finally,the results suggest that there were constraints placed on the risk management strategies currently utilized by professionals working in the public sector.These constraints include insufficient support and buy-in from senior management and stakeholders,bureaucratic or administrative hurdles,inadequate policies and regulations,insufficient training and skill development opportunities,and insufficient resources.The study highlights the significance of tackling risk management in the realm of public procurement and offers valuable perspectives on avenues for enhancement,obstacles encountered by practitioners,and the necessity of thorough evaluation and revisions.Through the adoption of the suggestions originating from this study,governmental entities can improve their procurement risk management frameworks and guarantee improved adherence to risk management principles.

Strategies for Cultivating Public Funded Targeted Normal Students Based on Goal Management Theory : A Case Study of East, West and North Guangdong

Public funded targeted normal students are an important component of China's teacher team construction.Since its implementation in 2007,a large number of outstanding rural teachers who have been striving on the front line of education have been trained.Based on the theory of goal management,this paper explores the problems and countermeasures in the training of public funded targeted normal students.It strives to solve the problems of low willingness to teach and high default rates among public funded normal students,and hopes that the suggestions proposed in this paper can further promote the effective implementation of policies for public funded normal students.

Novel Hyper-Combined Public Key Based Cloud Storage Key Management Scheme

In order to ensure the security of cloud storage, on the basis of the analysis of cloud storage security requirements, this paper puts forward a kind of＂ hidden mapping hyper-combined public key management scheme based on the hyperelliptic curve crypto system, which is applicable to the distributed cloud storage. A series of operation processes of the key management are elaborated, including key distribution, key updating and key agreement, etc. Analysis shows that the scheme can solve the problem of large-scale key management and storage issues in cloud storage effectively. The scheme feathers high efficiency and good scalability. It is able to resist collusion attack and ensure safe and reliable service provided by the cloud storaee system

Operational Problems and Countermeasures of Public Elective Courses in Higher Vocational Colleges and Universities Based on the Perspective of Academic Affairs Management:Taking Guangdong C Vocational College as an Example

With the vigorous development of higher vocational education,public elective courses,as one of the core components of the higher vocational curriculum system,occupy a pivotal position.Based on the perspective of academic affairs management and taking Guangdong C Vocational College as an example,this paper meticulously analyzes the operational problems in the declaration,setting,teaching,and management of public elective courses through questionnaire surveys and other methods.It also puts forward a series of targeted solutions,with a view to continuously improving the teaching quality and management level of public elective courses.

A new group key management scheme based on keys tree, XOR operation and one-way function

By introducing XOR operation and one-way function chains to group key management schemes based on the keys tree, a new group key management scheme based on the keys tree, XOR operation and one-way function chains is proposed. Initialization, member adding and member evicting operations are introduced. The new scheme is compared with three other group key management schemes which are based on the keys tree： SKDC, LKH, and OFF. As far as transmission, computation and storage costs are concerned, the performance of the new group key management scheme is the best. The security problem of the new scheme is analyzed. This new scheme provides backward and forward security, i.e.. newly admitted group members cannot read previous multicast messages and evicted members cannot read future multicast messages, even with collusion by many arbitrarily evicted members.

Two-Party Authenticated Key Agreement in Certificateless Public Key Cryptography

Certificateless public key cryptography was introduced to overcome the key escrow limitation of the identity-based cryptography. It combines the advantages of the identity-based cryptography and the traditional PKI. Many certificateless public key encryption and signature schemes have been proposed. However, the key agreement in CL-PKE is seldom discussed. In this paper, we present a new certificateless two party authentication key agreement protocol and prove its security attributes. Compared with the existing protocol, our protocol is more 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 Authenticated Key Agreement Protocol Using Self-Certified Public Keys from Pairings

An efficient authenticated key agreement protocol is proposed, which makesuse of bilinear pairings and self-certificd public keys. Its security is based on the securityassumptions of the bilinear Diff ie-Hellman problem and the computational Diffie-Hellman problem.Users can choose their private keys independently. The public keys and identities of users can beverified implicitly when the session key being generating in a logically single step. A trusted KeyGeneration Center is no longer requiredas in the ID-based authenticated key agreement protocolsCompared with existing authenticated key agreement protocols from pairings, the. new proposedprotocol is more efficient and secure.

Public Key Cryptography Based on Ergodic Matrices over Finite Field

A new public key encryption scheme is proposed in this paper, which is based on a hard problem over ergodic matrices. The security of this scheme is equal to the MQ-problem： multivariate quadratic equations over finite fields. This problem has been shown to be NP-complete and can＇t be solved with polynomial time algorithm.

A practical and dynamic key management scheme for a user hierarchy

In this paper, we propose a practical and dynamic key management scheme based on the Rabin public key system and a set of matrices with canonical matrix multiplication to solve the access control problem in an arbitrary partially ordered user hierarchy. The advantage is in ensuring that the security class in the higher level can derive any of its successor’s secret keys directly and efficiently and show it is dynamic while a new security class is added into or a class is removed from the hierarchy. Even the ex-member problem can be solved efficiently. Moreover, any user can freely change its own key for some security reasons.

A New Proxy Signature Scheme with Message Recovery Using Self-Certified Public Key

A proxy signature scheme with message recovery using self-certified public key is proposed, which withstands public key substitution attacks, active attacks, and forgery attacks. The proposed scheme accomplishes the tasks of public key verification, proxy signature verification, and message recovery in a logically single step. In addition, the proposed scheme satisfies all properties of strong proxy signature and does not use secure channel in the communication between the original signer and the proxy signature signer.

A NEW KEY MANAGEMENT METHOD FOR AD HOC NETWORKS

Some security-sensitive fields like military scenarios are the main application areas of ad hoc networks.In those areas,security issues have to be considered seriously for the network.In this paper, a key management method based on the combined public key is proposed for ad hoc networks. Through this method,private and public key pairs can be distributed to nodes of ad hoc networks efficiently.No certificate or other authentic channel is needed while two nodes perform authentication and key agreement protocol.The key management method is especially suitable for ad hoc networks,which has no fixed infrastructure and has constrained resources.

Multivariate Public-Key Encryption Scheme Based on Error Correcting Codes

Advances in quantum computers pose potential threats to the currently used public-key cryptographic algorithms such as RSA and ECC.As a promising candidate against attackers equipped with quantum computational power,Multivariate Public-Key Cryptosystems(MPKCs)has attracted increasing attention in recently years.Unfortunately,the existing MPKCs can only be used as multivariate signature schemes,and the way to construct an efficient MPKC enabling secure encryption remains unknown.By employing the basic MQ-trapdoors,this paper proposes a novel multivariate encryption scheme by combining MPKCs and code-based public-key encryption schemes.Our new construction gives a positive response to the challenges in multivariate public key cryptography.Thorough analysis shows that our scheme is secure and efficient,and its private key size is about 10 times smaller than that of McEliece-type cryptosystems.

Dynamic Cluster Key Management Scheme on Wireless Sensor Networks

Wireless sensor networks are open architectures, so any potential threat can easily intercept, wiretap and counterfeit the information. Therefore, the safety of WSN is very important. Since any single key system cannot guarantee the security of the wireless sensor network for communications, this paper introduces a hierarchical key management scheme based on the different abilities of different sensor nodes in the clustered wireless sensor network. In this scheme, the nodes are distributed into several clusters, and a cluster head must be elected for each cluster. Private communication between cluster heads is realized through the encryption system based on the identity of each head while private communication between cluster nodes in a same cluster head is achieved through the random key preliminary distribution system. Considering the characteristics of WSN, we adopt dynamic means called dynamic cluster key management scheme to deal with master key, so master key will be updated according to the changed dynamic network topology. For cluster head node plays a pivotal role in this scheme, a trust manage-ment system should be introduced into the election of the cluster head which will exclude the malicious node from outside the cluster, thus improve the whole network security.

An Internet Key Exchange Protocol Based on Public Key Infrastructure

Internet key exchange (IKE) is an automated key exchange mechanism that is used to facilitate the transfer of IPSec security associations (SAs). Public key infrastructure (PKI) is considered as a key element for providing security to new distributed communication networks and services. In this paper, we concentrate on the properties of the protocol of Phase 1 IKE. After investigating IKE protocol and PKI technology, we combine IKE protocol and PKI and present an implementation scheme of the IKE based on PKI. Then, we give a logic analysis of the proposed protocol with the BAN-logic and discuss the security of the protocol. The result indicates that the protocol is correct and satisfies the security requirements of Internet key exchange.

Key-insulated encryption based group key management for wireless sensor network

The key exposure problem is a practical threat for many security applications. In wireless sensor networks (WSNs), keys could be compromised easily due to its limited hardware protections. A secure group key management scheme is responsible for secure distributing group keys among valid nodes of the group. Based on the key-insulated encryption (KIE), we propose a group key management scheme (KIE-GKMS), which integrates the pair-wise key pre-distribution for WSN. The KIE-GKMS scheme updates group keys dynamically when adding or removing nodes. Moreover, the security analysis proves that the KIE-GKMS scheme not only obtains the semantic security, but also provides the forward and backward security. Finally, the theoretical analysis shows that the KIE-GKMS scheme has constant performance on both communication and storage costs in sensor nodes.

Key Management Using Certificate-Based Cryptosystem in Ad Hoc Networks

This paper proposed a distributed key management approach by using the recently developed concepts of certificate-based cryptosystem and threshold secret sharing schemes. Without any assumption of prefixed trust relationship between nodes, the ad hoc network works in a self-organizing way to provide the key generation and key management services using threshold secret sharing schemes, which effectively solves the problem of single point of failure. The proposed approach combines the best aspects of identity-based key management approaches (implicit certification) and traditional public key infrastructure approaches (no key escrow).

An Authenticated Dynamic Key Management Scheme for Clustered Sensor Networks

Secure sensor networks has received much attention in the last few years.A sensor network always works unattended possibly in a hostile environment such as a battlefield.In such environments,sensor networks are subject to node capture.Constrained energy,memory,and computational capabilities of sensor nodes mandate a clever design of security solutions to minimize overhead while maintaining secure communication over the lifespan of the network.In this paper,an authenticated dynamic key management scheme,ADKM has been proposed.It provides efficient,scalable,and survivable dynamic keying in a clustered sensor network with a large number of sensor nodes.ADKM employs a combinatorial exclusion basis system (EBS) for efficiency and one-way hash chains for authentication.Analysis of security and performance demonstrate that ADKM is efficient in security of sensor networks.