Digital signature schemes are a foundational cryptographic building block in certification and the projection of trust. Based on a signature scheme on committed graphs, we propose a framework of certification and proof methods to sign topology graphs and to prove properties of their certificates in zero-knowledge. This framework allows an issuer, such as an auditing system, to sign the topology representation of an infrastructure. The prover, such as an infrastructure provider, can then convince a verifier of topology properties including connectivity and isolation without disclosing the blueprint of the topology itself. By that, we can certify the structure of critical systems while still maintaining confidentiality. We offer zero-knowledge proofs of knowledge for a general specification language of security goals for virtualized infrastructures such that high-level security goals can be proven over topology certificates. We offer an efficient and practical construction, built upon the Camenisch-Lysyanskaya signature scheme, honest-verifier proofs and the strong RSA assumption.
The problem of secure multi-party computation(SMPC) is one of the most fundamental problems in information security. First, we introduce the basic concept of SMPC and four SMPC basic agreement: key distribution,oblivious transfer, bit commitment and zero knowledge proof. Secondly, we separately illustrate commitment schemes  commitment transfer protocol, commitment sharing protocol and commitment multiplication protocol. Finally, we present unconditionally secure multi-party computation with a passive adversary, an active adversary, general adversary structures.
During the execution of a business process users need to be authenticated by multiple component service providers, while their identities need to be shared and propagated across multi-domain in a privacy-preserving fashion. An anonymous credential-based identity verification scheme is proposed to address privacy issue. Users establish trust relationship with the federation by running the enrollment protocol, which is based on zero-knowledge proof of a set of committed attributes. The IdP cannot learn identity-related information about the user. Anonymous credentials issued by the IdP allow users to selectively disclose attributes as required and prove them in an untraceable and unlinkable way, where the IdP cannot trace the showing of credential and component service providers cannot address multiple transactions to the same user even if they collude either. With the proposed attributes proof protocols, users can prove AND and OR relation over multiple attributes, and interval and inequality relation over a single attribute as well.
Smart grid is the intelligent power grid, in which Scheduling system is the most important part. In this paper, we will introduce a new schedule system based on contract net protocol improved scheduling efficiency. As one of the most important coordination mechanism, contract net protocol (CNP) has been extensively studied in many areas, and many other techniques can also be used to improve the quality of decision. The new CNP is based on trust mechanism, that makes the system more efficient scheduling. Experimental results show that the initiators with trust model almost steadily get the best participants no matter the environment is honest-dominated or dishonest-dominated. Even in the dishonest-dominated environment, this approach gets better results and is proved valuable.
J-PAKE is a Password-Authenticated Key Exchange protocol, proposed in 2008 and presented again in 2010 and 2011. It does not require any public key infrastructure but uses zero-knowledge proofs. J-PAKE has been submitted as a candidate for the IEEE P1363.2 standard for password-based public key cryptography, and included in OpenSSL and OpenSSH. Since December 2010, J-PAKE has been used in Mozilla Firefox web browser. In this paper, we show that J-PAKE is vulnerable to password compromise impersonation attack, replay attack, and unknown key-share attack. We also propose some improvements for thwarting replay and unknown key-share attacks.
In a hybrid network system which combines a wired network adopting PKI authentication and a wireless network adopting IBE authentication,it is difficult to authenticate other nodes in view of the different security polices and cryptosystem.To solve this problem,a cross-domain authentication scheme based on zero knowledge proof is proposed.An agency node is settled between the two heterogeneous trustworthy domains to certificate nodes'commitments in the zero knowledge proof.Then a authentication protocol between heterogeneous trustworthy domains is designed to realize the authentication between nodes in different domains,and the correctness,security and efficiency of the protocol are analyzed.The results show that the proposed protocol is feasible and effective.
The interactive zero-knowledge proof protocol for the graph isomorphism was studied,and subgraph isomorphism certification algorithm was proposed by analyzing the basic model based on zeroknowledge proof.The security of most of the zero knowledge proofs was guaranteed by complex mathematical operations and large scale computations of interaction on both sides.Modulo operation was directly applied to the file encryption,and that only required a few parameters,which greatly reduced the storage space,and the method was simple and effective.Because of the characteristic of the zero-knowledge proof,it has better level of security,and meets the demand of basic protection.The algorithm is suitable for the authentication algorithm of login and vote that cannot be traced.
In this short paper, we present a Fiat-Shamir type transform that takes any Sigma protocol for a relation R and outputs a non-interactive zero-knowledge proof (not of knowledge) for the associated language L R , in the common reference string model. As in the Fiat-Shamir transform, we use a hash function H. However, zero-knowledge is achieved under standard assumptions in the common reference string model (without any random oracle), and soundness is achieved in the non-programmable random oracle model. The concrete computational complexity of the transform is only slightly higher than the original Fiat-Shamir transform.
On the basis of analyzing the shortcomings of traditional authentication mechanism synthetically, the paper presents a new kind of P2P identity authentication model. In the new P2P Identity authentication model, it authenticates the identity of nodes by using a new Zero-Knowledge proof identification scheme which combines the advantage of RSA. Besides, during the process of validating nodes ’ identity, CA (Center Authentication) doesn’t need to participate in. At last, Simulation results show that the new P2P identity authentication method can improve the safety of network effectively.
The privacy of users has rapidly become one of the most pervasive and stringent requirements in distributed computing. Designing and implementing privacy-preserving distributed systems, however, is challenging since these systems also have to fulfill seemingly conflicting security properties and system requirements: e.g., authorization and accountability require some form of user authentication and session management necessarily involves some form of user tracking. In this work, we present a solution based on declarative design. The core component of our framework is a logic-based declarative API for data processing that exports methods to conveniently specify the system architecture and the intended security properties, and conceals the cryptographic realization. Invisible to the programmer, the implementation of this API relies on a powerful combination of digital signatures, non-interactive zero-knowledge proofs of knowledge, pseudonyms, and reputation lists. We formally proved that the cryptographic implementation enforces the security properties expressed in the declarative specification. The systems produced by our framework enjoy interoperability and open-endedness: they can easily be extended to offer new services and cryptographic data can be shared and processed by different services, without requiring any extra bootstrapping phase or interaction among parties. We implemented the API in Java and conducted an experimental evaluation to demonstrate the practicality of our approach.
With the constant proliferation of information systems around the globe, the need for decentralized and scalable data sharing mechanisms has become a major factor of integration in a wide range of applications. Literature on information integration across autonomous entities has tacitly assumed that the data of each party can be revealed and shared to other parties. A lot of research, concerning the management of heterogeneous sources and database integration, has been proposed, for example based on centralized or distributed mediators that control access to data managed by different parties. On the other hand, real life data sharing scenarios in many application domains like healthcare, e-commerce market, e-government show that data integration and sharing are often hampered by legitimate and widespread data privacy and security concerns. Thus, protecting the individual data may be a prerequisite for organizations to share their data in open environments such as Internet. Work undertaken in this thesis aims to ensure security and privacy requirements of software systems, which take the form of web services, using query rewriting principles. The user query (SPARQL query) is rewritten in such a way that only authorized data are returned with respect to some confidentiality and privacy preferences policy. Moreover, the rewriting algorithm is instrumented by an access control model (OrBAC) for confidentiality constraints and a privacy-aware model (PrivOrBAC) for privacy constraints. A secure and privacy-preserving execution model for data services is then defined. Our model exploits the services¿ semantics to allow service providers to enforce locally their privacy and security policies without changing the implementation of their data services i.e., data services are considered as black boxes. We integrate our model to the architecture of Axis 2.0 and evaluate its efficiency in the healthcare application domain.
It is important that during the execution of a business process built from composable Web services from multiple domains, the component service be able to verify the identity of the user to check it has the required permissions for accessing the services, while at the same time identity attributes need to be protected properly as they can be target of attacks. In such context, we propose a privacy-preserved multi-domain identity attributes verification model BPVrfy. It extends federate identity management with support for multiple identity verification policies and privacy enhancement. Identity attributes verification process is partitioned into three sub-procedures consisting of attribute provision, federation enrollment and attributes transfer, and then a series of protocols based on cryptographic schemes is proposed respectively. BPVrfy adopts Perdersen Commitment, Zero-Knowledge Proof of Knowledge, BGLS Aggregate Signature and Certificate-Based Signature (CBS) cryptographic schemes together to give a privacy-preserved federate identity attributes verification solution for multi-domain Web services-based business processes.
Controlled access to confidential information and resources is a critical element in security systems. Role-based access control (RBAC) has gained widespread usage in modern enterprise systems. Extensions have been proposed to RBAC for incorporating spatial constraints into such systems. Several solutions have been proposed for such models and many researchers are now focusing on enforcing system policies. In this paper we propose a security framework for RBAC systems with spatial constraints based on identity-based encryption. In our framework, we use identity-based encryption with zero knowledge proof (ZKP) to provide authentication and information security. We also show how Near Field Communication (NFC) can be used to establish the integrity of a user's proof of location. Simulation results in Java validate our model. Furthermore, security analysis has been done to show how our framework protects against well-known attacks.
In this work we describe the PriSM framework for decentralized deployment of a federation of autonomous social networks (ASN). The individual ASNs are centrally managed by organizations according to their institutional needs, while cross-ASN interactions are facilitated subject to security and confidentiality requirements specified by administrators and users of the ASNs. Such decentralized deployment, possibly either on private or public clouds, provides control and ownership of information/flow to individual organizations. Lack of such complete control (if third party online social networking services were to be used) has so far been a great barrier in taking full advantage of the novel communication mechanisms at workplace that have however become commonplace for personal usage with the advent of Web 2.0 platforms and online social networks. PriSM provides a practical solution for organizations to harness the advantages of online social networking both in intra/inter-organizational settings without sacrificing autonomy, security and confidentiality needs.
The migration of web applications to Cloud computing platform has raised concerns about the privacy of sensitive data belonging to the consumers of cloud services. The traditional form of security tokens like username/password used to access cloud services are prone to phishing attacks and hence do not provide complete security. In this work we propose to extend the Microsoft's CardSpace identity management tool, to include more robust security tokens using the zero knowledge proof concept. These security tokens are in the form of SAML token supported by Windows Communication Foundation (WCF) and hence can prove interoperable with the existing security platforms.
Sebastian Ries, Marc Fischlin, Leonardo A. Martucci, Max Muuhlhauser
The topics of trust and privacy are more relevant to users of online communities than ever before. Trust models provide excellent means for supporting users in their decision making process. However, those models require an exchange of information between users, which can pose a threat to the users' privacy. In this paper, we present a novel approach for a privacy preserving computation of trust. Besides preserving the privacy of the recommenders by exchanging and aggregating recommendations under encryption, the proposed approach is the first that enables the trusting entities to learn about the trustworthiness of their recommenders at the same time. This is achieved by linking the minimum amount of information that is required for the learning process to the actual recommendation and by using zero-knowledge proofs for assuring the correctness of this additional information.
Nan Guo, Tianhan Gao, Bin Zhang, Ruchith Fernando · 5 authors
An aggregated privacy-preserving identity verification scheme is proposed for composite Web services. It aggregates multiple component providers' interactions of identity verification to a single one involving the user. Besides, it protects users from privacy disclosure through the adoption of zero-knowledge of proof of knowledge. This approach can dramatically reduce the computation time, independently on the number of identity attributes and component providers.
Shlomi Dolev, Panagiota N. Panagopoulou, Mikaël Rabie, Elad M. Schiller · 5 authors
Players in a game are assumed to be totally rational and absolutely smart. However, in reality all players may act in non-rational ways and may fail to understand and find their best actions. In particular, participants in social interactions, such as lotteries and auctions, cannot be expected to always find by themselves the "best-reply" to any situation. Indeed, agents may consult with others about the possible outcome of their actions. It is then up to the counselee to assure the rationality of the consultant's advice. We present a distributed computer system infrastructure, named rationality authority, that allows safe consultation among (possibly biased) parties. The parties' advices are adapted only after verifying their feasibility and optimality by standard formal proof checkers. The rationality authority design considers computational constraints, as well as privacy and security issues, such as verification methods that do not reveal private preferences. Some of the techniques resembles zero-knowledge proofs. A non-cooperative game is presented by the game inventor along with its (possibly intractable) equilibrium. The game inventor advises playing by this equilibrium and offers a checkable proof for the equilibrium feasibility and optimality. Standard verification procedures, provided by trusted (according to their reputation) verification procedures, are used to verify the proof. Thus, the proposed rationality authority infrastructure facilitates the applications of game theory in several important real-life scenarios by the use of computing systems.
An attack is mounted on a group signature scheme based on lattice posted in Asia Crypt 2010.It shows the group signature scheme is vulnerable to trap attacks and a dishonest group manager can get all group members′ signing keys and then forge all group members′ valid signatures.Meanwhile,the scheme can′t increase or delete group members flexibly and efficiently which is not applicable to dynamic groups.Every time a new member joins,the system has to update the public key and all group members′ signing keys which are of huge calculation and low efficiency.Also,the scheme doesn′t provide an effective method to revoke group members.Using statistical zero-knowledge proofs and time parameters,an improved scheme based on the hardness of the closest vector problem is proposed.The improved scheme is anti-trap attacks and can dynamic increase or deletes group members more efficiently and applicably.