A P2P Optimistic Fair Exchange (OFE) Scheme For Personal Health Records Using Blockchain Technology

In today’s digital world, it is common to exchange sensitive data between different parties. There are many examples of sensitive data or documents that require a digital exchange, such as banking information, insurance data, health records. In many cases, the exchange exists between unknown and untrusted parties. Therefore, it is essential to execute the data exchange over a fair non-repudiation protocol. In digital communication, non-repudiation is undeniable evidence of one’s responsibility regarding the validity of any data he shares/receives. Usually, this is achieved by the use of a cryptographic digital signature. In this case, the parties cannot deny the authenticity of their digital signature. The protocol satisfies the fairness property if and only if it does not give the sender any advantages over the receiver or vice versa, at any step during the exchange process. Combining fair exchange and non-repudiation for digital exchange is critical in many applications and can be acquired with or without the involvement of any trusted third party (TTP). However, without the involvement of TTP, fairness becomes probabilistic, and the involvement of TTP can cause significant dependency on the third party. Therefore, a peer-to-peer (P2P) (aka offline) fair non-repudiation protocol that does not require a trusted third-party is desirable in many applications. Blockchain is designed in such a way that the network can handle the trustless environment and deliver the correct result. Thus, if the exchanges are done leveraging Blockchain, it will ensure true fairness, and at the same time, none of the participants have to deal with the trust issue. In this thesis we propose a P2P fair non-repudiation data exchange scheme by leveraging Blockchain and distributed ledger technology. The scheme combines on-chain and off-chain communication patterns to enable the exchange of personal health records between patients and healthcare providers. We provide an informal reasoning of the proposed scheme. Moreover, we propose a design and implementation agnostic to existing Blockchain platforms to enable unbiased evaluation of the proposed scheme. Finally, we make a comparative analysis of the result derived from our approach with the existing one

Optimistic fair transaction processing in mobile ad-hoc networks

Mobile ad-hoc networks (MANETs) are unstable. Link errors, which are considered as an exception in fixed-wired networks must be assumed to be the default case in MANETs. Hence designing fault tolerant systems efficiently offering transactional guarantees in these unstable environments is considerably more complex. The efficient support for such guarantees is essential for business applications, e.g. for the exchange of electronic goods. This class of applications demands for transactional properties such as money and goods atomicity. Within this technical report we present an architecture, which allows for fair and atomic transaction processing in MANETs, together with an associated application that enables exchange of electronic tokens

Design and implementation of extensible middleware for non-repudiable interactions

PhD ThesisNon-repudiation is an aspect of security that is concerned with the creation of irrefutable audits of an interaction. Ensuring the audit is irrefutable and verifiable by a third party is not a trivial task. A lot of supporting infrastructure is required which adds large expense to the interaction. This infrastructure comprises, (i) a non-repudiation aware run-time environment, (ii) several purpose built trusted services and (iii) an appropriate non-repudiation protocol. This thesis presents design and implementation of such an infrastructure. The runtime environment makes use of several trusted services to achieve external verification of the audit trail. Non-repudiation is achieved by executing fair non-repudiation protocols. The Fairness property of the non-repudiation protocol allows a participant to protect their own interests by preventing any party from gaining an advantage by misbehaviour. The infrastructure has two novel aspects; extensibility and support for automated implementation of protocols. Extensibility is achieved by implementing the infrastructure in middleware and by presenting a large variety of non-repudiable business interaction patterns to the application (a non-repudiable interaction pattern is a higher level protocol composed from one or more non-repudiation protocols). The middleware is highly configurable allowing new non-repudiation protocols and interaction patterns to be easily added, without disrupting the application. This thesis presents a rigorous mechanism for automated implementation of non-repudiation protocols. This ensures that the protocol being executed is that which was intended and verified by the protocol designer. A family of non-repudiation protocols are taken and inspected. This inspection allows a set of generic finite state machines to be produced. These finite state machines can be used to maintain protocol state and manage the sending and receiving of appropriate protocol messages. A concrete implementation of the run-time environment and the protocol generation techniques is presented. This implementation is based on industry supported Web service standards and services.EPSRC, The Hewlett Packard Arjuna La

Lime: Data Lineage in the Malicious Environment

Intentional or unintentional leakage of confidential data is undoubtedly one of the most severe security threats that organizations face in the digital era. The threat now extends to our personal lives: a plethora of personal information is available to social networks and smartphone providers and is indirectly transferred to untrustworthy third party and fourth party applications. In this work, we present a generic data lineage framework LIME for data flow across multiple entities that take two characteristic, principal roles (i.e., owner and consumer). We define the exact security guarantees required by such a data lineage mechanism toward identification of a guilty entity, and identify the simplifying non repudiation and honesty assumptions. We then develop and analyze a novel accountable data transfer protocol between two entities within a malicious environment by building upon oblivious transfer, robust watermarking, and signature primitives. Finally, we perform an experimental evaluation to demonstrate the practicality of our protocol

Fair exchange in e-commerce and certified e-mail, new scenarios and protocols

We are witnessing a steady growth in the use of Internet in the electronic commerce field. This rise is promoting the migration from traditional processes and applications (paper based) to an electronic model. But the security of electronic transactions continues to pose an impediment to its implementation. Traditionally, most business transactions were conducted in person. Signing a contract required the meeting of all interested parties, the postman delivered certified mail in hand, and when paying for goods or services both customer and provider were present. When all parties are physically present, a transaction does not require a complex protocol. The participants acknowledge the presence of the other parties as assurance that they will receive their parts, whether a signature on a contract, or a receipt, etc. But with e-commerce growing in importance as sales and business channel, all these transactions have moved to its digital counterpart. Therefore we have digital signature of contracts, certified delivery of messages and electronic payment systems. With electronic transactions, the physical presence is not required,moreover, most of the times it is even impossible. The participants in a transaction can be thousands of kilometers away from each other, and they may not even be human participants, they can be machines. Thus, the security that the transaction will be executed without incident is not assured per se, we need additional security measures. To address this problem, fair exchange protocols were developed. In a fair exchange every party involved has an item that wants to exchange, but none of the participants is willing to give his item away unless he has an assurance he will receive the corresponding item from the other participants. Fair exchange has many applications, like digital signature of contracts, where the items to be exchanged are signatures on contracts, certified delivery of messages, where we exchange a message for evidence of receipt, or a payment process, where we exchange a payment (e-cash, e-check, visa, etc.) for digital goods or a receipt. The objective of this dissertation is the study of the fair exchange problem. In particular, it presents two new scenarios for digital contracting, the Atomic Multi- Two Party (AM2P) and the Agent Mediated Scenario (AMS), and proposes one optimistic contract signing protocol for each one. Moreover, it studies the efficiency of Multi-Party Contract Signing (MPCS) protocols from their architecture point of view, presenting a new lower bound for each architecture, in terms of minimum number of transactions needed. Regarding Certified Electronic Mail (CEM), this dissertation presents two optimistic CEMprotocols designed to be deployed on thecurrent e-mail infrastructure, therefore they assume the participation of multiple Mail Transfer Agents (MTAs). In one case, the protocol assumes untrusted MTAs whereas in the other one it assumes each User Agent (UA) trusts his own MTA. Regarding payment systems, this dissertation presents a secure and efficient electronic bearer bank check scheme allowing the electronic checks to be transferred fairly and anonymously.L’ús d’Internet en l’àmbit del comerç electrònic està experimentant un creixement estable. Aquest increment d’ús està promovent lamigració de processos tradicionals i aplicacions (basades en paper) cap a un model electrònic. Però la seguretat de les transaccions electròniques continua impedint la seva implantació. Tradicionalment, la majoria de les transaccions s’han dut a terme en persona. La firma d’un contracte requeria la presència de tots els firmants, el carter entrega les cartes certificades enmà, i quan es paga per un bé o servei ambdós venedor i comprador hi són presents. Quan totes les parts hi són presents, les transaccions no requereixen un protocol complex. Els participants assumeixen la presència de les altres parts com assegurança que rebran el que esperen d’elles, ja sigui la firma d’un contracte, un rebut d’entrega o un pagament. Però amb el creixement del comerç electrònic com a canal de venda i negoci, totes aquestes transaccions s’hanmogut al seu equivalent en el món electrònic. Així doncs tenim firma electrònica de contractes, enviament certificat de missatges, sistemes de pagament electrònic, etc. En les transaccions electròniques la presència física no és necessària, de fet, la majoria de vegades és fins it tot impossible. Els participants poden estar separats permilers de kilòmetres, i no és necessari que siguin humans, podrien sermàquines. Llavors, la seguretat de que la transacció s’executarà correctament no està assegurada per se, necessitem proporcionar mesures de seguretat addicionals. Per solucionar aquest problema, es van desenvolupar els protocols d’intercanvi equitatiu. En un intercanvi equitatiu totes les parts involucrades tenen un objecte que volen intercanviar, però cap de les parts implicades vol donar el seu objecte si no té la seguretat que rebrà els objectes de les altres parts. L’intercanvi equitatiu té multitud d’aplicacions, com la firma electrònica de contractes, on els elements a intercanviar son firmes de contractes, enviament certificat demissatges, on s’intercanvien unmissatge per una evidència de recepció, o un procés de pagament, on intercanviemun pagament (e-cash, visa, e-xec, etc.) per bens digitals o per un rebut. L’objectiu d’aquesta tesi és estudiar el problema de l’intercanvi equitatiu. En particular, la tesi presenta dos nous escenaris per a la firma electrònica de contractes, l’escenari multi-two party atòmic i l’escenari amb agents intermediaris, i proposa un protocol optimista per a cada un d’ells. A més, presenta un estudi de l’eficiència dels protocols de firma electrònica multi-part (Multi-Party Contract Signing (MPCS) protocols) des del punt de vista de la seva arquitectura, presentant una nova fita per a cada una, en termes de mínim nombre de transaccions necessàries. Pel que fa al correu electrònic certificat, aquesta tesi presenta dos protocols optimistes dissenyats per a ser desplegats damunt l’infraestructura actual de correu electrònic, per tant assumeix la participació demúltiples agents de transferència de correu. Un dels protocols assumeix que cap dels agents de transferència de correu participants és de confiança,mentre que l’altre assumeix que cada usuari confia en el seu propi agent. Pel que fa a sistemes de pagament, la tesi presenta un esquema de xec bancari al portador, eficient i segur, que garanteix que la transferència dels xecs es fa demanera anònima i equitativa

Non-repudiation in pure mobile ad hoc network

Within the last decade, the use of wireless technologies has become more prevalent. Wireless networks have flexible architectures with data transferred via radio waves and can be divided into two categories; infrastructure-based wireless networks and mobile ad hoc network. The mobile ad hoc network (MANET) is an autonomous system which can be dynamically built without pre-existing infrastructure or a trusted third party (TTP). Due to these infrastructure-less and self-organized characteristics, MANET encounters different problems from infrastructure-based wired network, such as key management, power shortage, and security issues. This paper will further divide MANETs into pure ad hoc networks which do not contain a TTP and organized ad hoc networks which contain an offline TTP, and then focus on the security issues especially the non-repudiation issue between two mobile nodes which communicate in pure ad hoc networks

Optimistic Non-repudiation Protocol Analysis

The original publication is available at www.springerlink.com ; ISBN 978-3-540-72353-0 (Pring) 0302-9743 (Online) 1611-3349International audienceNon-repudiation protocols with session labels have a number of vulnerabilities. Recently Cederquist, Corin and Dashti have proposed an optimistic non-repudiation protocol that avoids altogether the use of session labels. We have specified and analysed this protocol using an extended version of the AVISPA Tool and one important fault has been discovered. We describe the protocol, the analysis method, show two attack traces that exploit the fault and propose a correction to the protocol

Automatic Methods for Analyzing Non-repudiation Protocole with an Active Intruder

International audienceNon-repudiation protocols have an important role in many areas where secured transactions with proofs of participation are necessary. Formal methods are clever and without error, therefore using them for verifying such protocols is crucial. In this purpose, we show how to partially represent non-repudiation as a combination of authentications on the Fair Zhou-Gollmann protocol. After discussing the limitations of this method, we define a new one based on the handling of the knowledge of protocol participants. This second method is general and of natural use, as it consists in adding simple annotations in the protocol specification. It is very easy to implement in tools able to handle participants knowledge. We have implemented it in the AVISPA Tool and analyzed the optimistic Cederquist-Corin-Dashti protocol, discovering two attacks. This extension of the AVISPA Tool for handling non-repudiation opens a highway to the specification of many other properties, without any more change in the tool itself