Extended Asymmetric Group Key Agreement for Dynamic Groups and Its Applications

Group Key Agreement(GKA)is a cryptographic primitive allowing two or more entities to negotiate a shared session key over public networks.In existing GKA models,it is an open problem to construct a one-round multi-party GKA protocol.Wu et al.recently proposed the concept of asymmetric group key agreement(ASGKA)and realized a one-round ASGKA protocol,which affirmatively answers the above open problem in a relaxed way.However,the ASGKA protocol only applies to static groups.To fill this gap,this paper proposes an extended ASGKA protocol based on the Wu et al.protocol.The extension allows any member to join and leave at any point,provided that the resulting group size is not greater than n.To validate the proposal,extensive experiments are performed and the experimental results show that our protocol is more effective than a plain realization of the Wu et al.protocol for dynamic groups.The extended protocol is also more efficient than the up-to-date dynamic GKA protocol in terms of communication and computation.

Efficient Dynamic Threshold Group Signature Scheme Based on Elliptic Curve Cryptosystem

The short secret key characteristic of elliptic curve cryptosystem （ECC） are integrated with the （ t, n ） threshold method to create a practical threshold group signature scheme characterized by simultaneous signing. The scheme not only meets the requirements of anonymity and traceability of group signature but also can withstand Tseng and Wang＇s conspiracy attack. It allows the group manager to add new members and delete old members according to actual application, while the system parameters have a little change. Cryptanalysis result shows that the scheme is efficient and secure.

Differential Representations of SO(4) Dynamical Group

In this paper we present systematic differential representations for the dynamical group SO(4).Theserepresentations include the left and the right differential representations and the left and the right adjoint differentialrepresentations in both the group parameter space and its coset spaces.They are the generalization of the differentialrepresentations of the SO(3) rotation group in the Euler angles.These representations may find their applications in thestudy of the physical systems with SO(4) dynamical symmetry.

On the new member’s subsecret distribution protocol in dynamic group secret-sharing

Secret-sharing is a common method to protect important data, such as the private key of a public-key system. Dynamic Group Secret-sharing (DGS) is a system where all of the members in a group hold a subsecret of the key information and where the number of members in the group is variable. This kind of secret-sharing is broadly used in many special distribution systems, such as Self-secure Ad-hoc Network. Distributing this subsecret to a new member when he enters the group is the common method that ensures all the members participate in the same secret-sharing. However, no’atisfactory subsecret distribution scheme exists at present. This paper proposes a new protocol that tries to satisfy both security and efficiency.

A New Dynamic Group Signature Scheme

In this paper, a new dynamic group signature scheme is proposed. It allows the group manager to increase or delete group members flexibly. Furthermore, the length of group signatures, as well as the computational effort for signing, verifying and opening are very small and independent of the number of group members and deleted group members. So it is efficient.

Security Analysis of Broadcaster Group Key Exchange Protocols

Group key exchange protocols are basic protocols to provide privacy and integrity in secure group communication. This paper discusses the security of one type of group key exchange protocols and defines the kind of protocols as broadcaster group protocols. It points out two attacks on this kind of protocols. The first attack can be avoided by using fresh values in each action during one session of the group protocol. The second attack should be related with concrete application. It also proposes a dynamic key agreement protocol as an example of solutions at the last part of the paper.

The Game Model Analysis between the Individual and the Group

This paper analyses the game model between the individual and the group that has the characteristics of Stackelberg model in traditional game theory and replicator dynamic model in evolutionary game theory. In the first phase of game, the bounded rationality group players adopt the replicator dynamic behavior. Secondly, the full rationality individual player decides the own response function by the strategies distribution of group players. The shortsighted individual player will take the risk-dominant strategy. This model has some unique characteristics.

Phase transition in a two-dimensional Ising ferromagnet based on the generalized zero-temperature Glauber dynamics

At zero temperature, based on the Ising model, the phase transition in a two-dimensional square lattice is studied using the generalized zero-temperature Glauber dynamics. Using Monte Carlo （MC） renormalization group methods, the static critical exponents and the dynamic exponent are studied; the type of phase transition is found to be of the first order.

Analyzing Cults and Saving Believers on Cults from the Perspectives of Psychology

There is cult leader who has not studied the psychology in a systematic way, but he is very good at using some psychology principles to capture a large number of believers and to make them follow him with their whole hearts. This article takes the need theory, the psychological frustration theory, the cognitive process theory and the theory of group psychological motivation as the principles, and obtaining the event in the actual struggle with the cult, the author reveals how the cult sets up the swindle with these theories and how the cult organization is developed fast and how to control cult believers and how they provide a service to themselves. The writers argue that when the cult leader crazily steals the psychological theory to deceive others and murder others and to loot money, we also should wave the psychological sword, and should use the psychological theory and methods against the cult to rescue the practitioners captured by cults, and the article also provides a strategy and method which can be a reference.

A P2P Reference Model

P2P is a complex system.Many researches on P2P architecture have been done.These researches have provided valuable references for the standardization of P2P technology.However,the standardization can not be achieved because there are still some problems in existing studies.This paper proposes a 5-layer reference model which clearly defines the functionalities of each layer,and distinctly describes the interface and the relationship between layers.This model is able to clearly show the internal structure of P2P system and the working process of data flow in P2P system.Validation shows that this model is general and rational.

LAGRANGIAN VECTOR FIELD ON KOHLER MANIFOLD

In this paper.we discuss Lagrangian vector field on Kahler manifold and use it to describe and solve some problem in Newtonican and Lagrangian Mechanics on Kahler Manifold.

A fully dynamic forward-secure group signature from lattice

A forward-secure group signature(FSGS)ensures the unforgeability of signatures in the past time period despite signing secret key is leaked in the current time period.As we know,traditional FSGS schemes are mostly relying on number-theoretic assumptions unable to resist quantum attacks.Therefore,we present an efficient lattice-based fully dynamic(ie.users can flexibly join or quit the group)forward-secure group signature(DFSGS)by combining an improved version of FSGS scheme proposed by Ling.Based on an efficient zero-knowledge argument,we construct argument of knowledge of the committed value and the plaintext that help with privacy protection.Our DFSGS scheme is proved to be anonymous and forward-secure traceable relying on short integer solution and learning with errors assumptions in random oracle model.Moreover,the lengths of group public key and signature of our DFSGS scheme have been improved,and the length of user secret key has no connection with the quantity of group members.

A Novel Bit-level Image Encryption Method Based on Chaotic Map and Dynamic Grouping

In this paper,a novel bit-level image encryption method based on dynamic grouping is proposed.In the proposed method,the plain-image is divided into several groups randomly,then permutation-diffusion process on bit level is carried out.The keystream generated by logistic map is related to the plain-image,which confuses the relationship between the plain-image and the cipher-image.The computer simulation results of statistical analysis,information entropy analysis and sensitivity analysis show that the proposed encryption method is secure and reliable enough to be used for communication application.

A dynamic,secure,and efficient group key agreement protocol

The key challenge of dynamic peer communication is how to realize secure and efficient group key manage-ment.A two rounds key agreement protocol for dynamic peer group(DPG)is proposed in this paper.The protocol,which was obtained by combining the ElGamal encryption scheme with the ElGamal signature scheme,is efficient and simple.The protocol is proven secure against passive attack by using indistinguishable method.Moreover,both perfect forward secrecy(PFS)and key independence(KI)were achieved.Because the protocol is based on the broadcast channel,it is also suitable for key agreement in wireless communications,especially in ad-hoc networks.

An efficient fully dynamic group signature with message dependent opening from lattice

Message-dependent opening is one of the solutions to solve the problem of the tracing manager owns excessive power.In this paper,we present a new lattice-based fully dynamic group signature scheme with message-dependent opening by combining an improved version of the fully dynamic group signature scheme proposed by Ling et al and the double encryption paradigm.In addition,we propose an improved underlying zero knowledge protocol,it has a soundness error 1 max(n,p)+1 that is better than the Stern-like protocol,which helps to bring down the communication complexity of the protocol and hence the signature scheme.Our scheme constrains the power of group managers by adding an admitter,and the signature size has a logarithmic relationship with the group size.

Dynamic multiple criteria group decision-making method based on intuitionistic fuzzy information

In the decision-making process,the decision information provided by decision makers over alter-natives may take the form of intuitionistic fuzzy numbers and come from different periods.The weight of information on decision makers,criteria,periods is usually completely unknown.To this issue,we first utilise hesitation degree information and introduce the concept of confi-dence degree function to determine the decision maker’s weights.Then we aggregate individual evaluation information into group evaluation information through intuitionistic fuzzy number weighted arithmetic averaging operator.We construct a nonlinear optimisation model to gain the criterion weights and apply the aggregate operator to gain the integrated rating value of alternatives in different periods,calculating the deviations of the integrated rating values with respect to their average.Then the period weights are been obtained by using the entropy method.According to the closeness coefficient between alternatives and ideal solution to sort the alternatives and select the optimal one.