Fairness is the vitally necessary for application of electronic transaction.A fair protocol is presented for message transfer in electronic commerce.The protocol is designed to assure when the protocol ends,both parties get the expected messages or nothing.The protocol,based on optimistic approach,uses convertible signature scheme and non-interactive zero-knowledge proof to achieve efficient transparent TTP.Also,the protocol generates standard GDH(gap diffie-hellman) signatures as the final non-repudiation evidences.All these efforts make the protocol efficient and easy to be fitted in existing systems.
Group-oriented identity authentication is designed to satisfy some special security demands.It help to prevent the cheat of inner fellows and improve the security level and availability of identity authentication system,as well as strengthening the system sur-vivability.Combined with general ElGamal digital signature,shamir secret sharing and zero-knowledge proof,a group-oriented identity authentication scheme is designed,which can effectively resist familiar personate and conspiracy attack.
A new efficient normative signature scheme,based on discrete logarithm assumption and factoring assumption is proposed.A zero knowledge proof protocol between the nominee and a third party to verify the signature is also constructed.This signature can be transformed into an undeniable and fail-stop signature if necessary.The efficiency of different nominative signature schemes is also compared.
Access Control is an important mechanism of information security. Role-Based Access Control is a famous access control approach with good flexibility. RBAC96 and ARBAC97 are classical RBAC models. The ARBAC97 model facilitates decentralized administration of RBAC. However, ARBAC97 has some shortcomings in the case of being used in an organization with autonomous subsidiaries. The member of an administrative role can operate directly in the role range of a junior administrative role, which violates the autonomy of subsidiaries. We propose a new model named N-RBAC to overcome this weakness. In N-RBAC, roles are arranged according to a hierarchical namespace structure. Thus the role hierarchy is constructed in a local space instead of in a global space. The N-RBAC model does a better work in decentralized role administration in those organizations composed of autonomous subsidiaries.
Delegation, whereby an entity gives some of its rights to other entities, is considered the cornerstone of decentralized authorization, and many access control frameworks proposed recently make delegation its central tenet. In these frameworks, delegation is commonly viewed as a transfer between two autonomous agents---the grantor and the grantee. But the situation can be considerably more complex, and more challenging, in the case the grantor belongs to an organization. Generally, employees are not autonomous agents, but their actions are subject to the regulations of their enterprise. In particular, if an employee transfers his rights to another agent, this transfer is subject to the enterprise delegation policies.In delegation frameworks, authorizing a request requires finding a valid chain of credentials that delegates the authority from the source (the local policy of the entity that serves the request) to the requester. Unfortunately, chain discovery is a computationally expensive and time consuming task. It was shown that, in the general case, chain discovery is undecidable, and in more restrictive cases, it is polynomial in the number of credentials available to the server. Verifying compliance with the terms of a delegation policy adds a considerable overhead to request authorization.This paper presents a framework that considerably reduces the time required to authorize a request. In this framework, a delegation chain is condensed into a single credential, called chained delegation certificate (CDC). A CDC attests that the owner has a certain right, and serves as proof that every link in the chain complies with the policy governing delegation of the right in question. When CDCs are used for authorization, a server does not need to verify compliance with the delegation policy, nor does it need to perform the chain discovery step, and therefore requests are served considerably faster.
By applying the secret sharing system and the zero knowledge proof protocol,this paper presents a new time constraint delegation of the decryption scheme based on trust agent platforms,which solves the problem that the accessed peer cannot offer instant data when it is offline.This scheme carries out encryption and decryption by using ElGamal cryptography.It defines the delegating-agents protocol,the produce of the delegation-key protocol and the decryption protocol,thus implementing the cheat-resisted and quorum controlled time constraint delegation of decryption.And the new scheme is supplemented to settle the problems of the key being renewed dynamically,the agent being added or deleted and the agent's information being maintained.Compared with the previous time constraint delegation of the decryption scheme,it improves security,flexibility and efficiency.
In this paper we define a decentralized management mechanism for the dynamic coalition characteristic of virtual organization. We propose an identity-based threshold signature scheme for joint management. We also propose the policy mode for joint management, which uses role-based access control mechanism for authorization policies definition, and voting mechanism for authorization decision-making. Our solution can satisfy the dynamic coalition requirement of virtual organization, and also guarantee the autonomous characteristic of participant organizations and grid entities. Privacy preservation is also provided for grid entities to interact with authorized entities. Authorization revocation mechanism is taken into consideration in this paper. The experimental performance also shows the scalability of the solution.
Omar Khadeer Hussain, Elizabeth Chang, Farookh Khadeer Hussain, Tharam S. Dillon · 5 authors
Risk is associated with almost every activity that is undertaken on a daily life. Risk associated with Trust, Security and Privacy. Risk is associated with transactions, businesses, information systems, environments, networks, partnerships, etc. Generally speaking, risk signifies the likelihood of financial losses, human casualties, business destruction and environmental damages. Risk indicator gives early warning to the party involved and helps avoid deserters. Until now, risk has been discussed extensively in the areas of investment, finance, health, environment, daily life activities and engineering. However, there is no systematic study of risk in Decentralised communication, which involves e-business, computer networks and service oriented environment. In this paper, we define risk associated with trusted communication in e-business and e-transactions; provide risk indicator calculations and basic application areas.
Vijayalakshmi Atluri, Soon Ae Chun, Pietro Mazzoleni
Workflow systems are gaining importance as an infrastructure for automating inter-organizational interactions, such as those in Electronic Commerce. In such an environment, a centralized Workflow Management System is not desirable because: (i) it can be a performance bottleneck, and (ii) the system s are inherently distributed, heterogeneous, and autonomous in nature. Decentralized execution of inter-organizational workflows may raise a number of security issues including those related to conflict-of-interest among competing organizations. In this paper, we first provide an approach to realize decentralized workflow execution, in which the workflow is divided into partitions, called self-describing workflows, and handled by a light weight workflow management component, called workflow stub, located at each organizational agent. Second, we identify the limitations of the traditional workflow model with respect to expressing the various types of join dependencies and extend the traditional workflow model suitably. Distinguishing the different types of dependencies among tasks is essential in the efficient execution of self-describing workflows. Finally, we recognize that placing the task execution agents that belong to the same conflict-of-interest class in one self-describing workflow may lead to unfair, and in some cases, undesirable results, akin to being on the wrong side of the Chinese wall. Therefore, to address the conflict-of-interest issues that arise in competitive business environments, we propose a decentralized workflow Chinese wall security model. We propose a restrictive partitioning solution to enforce the proposed model.
Jung Min Park, Edwin K. P. Chong, Howard Jay Siegel
Applications such as e-commerce payment protocols, elec-tronic contract signing, and certified e-mail delivery require that fair exchange be assured. A fair-exchange protocol al-lows two parties to exchange items in a fair way so that either each party gets the other's item, or neither party does. We describe a novel method of constructing very ef-ficient fair-exchange protocols by distributing the computa-tion of RSA signatures. Specifically, we employ multisig-natures based on the RSA-signature scheme. To date, the vast majority of fair-exchange protocols require the use of zero-knowledge proofs, which is the most computationally intensive part of the exchange protocol. Using the intrinsic features of our multisignature model, we construct protocols that require no zero-knowledge proofs in the exchange proto-col. Use of zero-knowledge proofs is needed only in the pro-tocol setup phase--this is a one-time cost. Furthermore, our scheme uses multisignatures that are compatible with the underlying standard (single-signer) signature scheme, which makes it possible to readily integrate the fair-exchange fea-ture with existing e-commerce systems.
We present the first constant-round non-malleable commitment scheme and the first constant-round non-malleable zero-knowledge argument system, as defined by Dolev, Dwork and Naor (1991). Previous constructions either used a non-constant number of rounds, or were only secure under stronger setup assumptions. An example of such an assumption is the shared random string model where we assume all parties have access to a reference string that was chosen uniformly at random by a trusted dealer. We obtain these results by defining an adequate notion of non-malleable coin-tossing, and presenting a constant-round protocol that satisfies it. This protocol allows us to transform protocols that are non-malleable in (a modified notion of) the shared random string model into protocols that are non-malleable in the plain model (without any trusted dealer or setup assumptions). Observing that known constructions of a non-interactive non-malleable zero-knowledge argument systems in the shared random string model (De Santis et. al., 2001) are in fact non-malleable in the modified model, and combining them with our coin-tossing protocol we obtain the results mentioned above. The techniques we use are different from those used in previous constructions of non-malleable protocols. In particular our protocol uses diagonalization and a non-black-box proof of security (in a sense similar to Barak's zero-knowledge argument (2001)).
A new multiple secrets sharing scheme, based on the intractability of the discrete logarithm (DL) and the RSA encryption algorithm is presented, in which the participants' shadows remain secret and can be reused, even if all subshadows are made public. Meanwhile, by using a zero-knowledge proof protocol, the validity verification of shadow and subshadow is also provided to prevent both dealer cheating and other participant cheating, and any freely given secrets without pre-computation by dealer can be reconstructed. The scheme can be applied to many areas such as conference key distribution, secure multi-part-computation, threshold signature etc.
For information protection system, based on Harn's digital signature scheme and zero knowledge proof, this paper presents a double way authentication access control scheme. The scheme is safer than previously proposed schemes. In the scheme, double way authentication may be done between a user and the system without exposing their secret information, and their sharing secret is used for authenticating the requesting user not to illegitimatimately access the protected information body. The scheme can perform the access operation in dynamic environments, such as change access privileges and insert /delete users or information bodies without implicating any user's secret key, and need not restructure the information protection system. Thus, the scheme's dynamic feature is perfect. The proposed double way authentication access control scheme's computation security, based upon Harn's digital signature scheme and Zero knowledge proof, does not lower than the computation complexity of solving “Discrete Logarithm Problem”.
Vijayalakshmi Atluri, Soon Ae Chun, Pietro Mazzoleni
Workflow systems are gaining importance as an infrastructure for automating inter-organizational interactions, such as those in Electronic Commerce. Execution of inter-organiz-ational workflows may raise a number of security issues including those related to conflict-of-interest among competing organizations. Moreover, in such an environment, a centralized Workflow Management System is not desirable because: (i) it can be a performance bottleneck, and (ii) the systems are inherently distributed, heterogeneous and autonomous in nature. In this paper, we propose an approach to realize decentralized workflow execution, in which the workflow is divided into partitions called self-describing workflows, and handled by a light weight workflow management component, called workflow stub, located at each organizational agent. We argue that placing the task execution agents that belong to the same conflict-of-interest class in one self-describing workflow may lead to unfair, and in some cases, undesirable results, akin to being on the wrong side of the Chinese wall. We propose a Chinese wall security model for the decentralized workflow environment to resolve such problems, and a restrictive partitioning solution to enforce the proposed model.