Network trust management in emergency situations

AbstractWe study the unique trust management, and more precisely reputation management and revocation of malicious nodes in the context of ad hoc networks used for emergency communications.Unlike in centralized systems, reputation management and revocation in ad hoc networks is non-trivial. This difficulty is due to the fact that the nodes have to collaboratively calculate the reputation value of a particular node and then revoke the node if the reputation value goes below a threshold. A major challenge in this scheme is to prevent a malicious node from discrediting other genuine nodes. The decision to revoke a node has to be communicated to all the nodes of the network. In traditional ad hoc networks the overhead of broadcasting the message throughout the network may be very high. We solve the problem of reputation management and node revocation in ad hoc networks of cell phones by using a threshold cryptography based scheme. Each node of the network would have a set of anonymous referees, which would store the reputation information of the node and issue reputation certificates to the node with timestamps. The misbehavior of a particular cell phone is reported to its anonymous referees, who issue certificates which reflect the positive and negative recommendations

Luottamuksenhallinta web-palveluympäristössä

Tutkielmassa käsitellään luottamuksenhallintaa web-palveluympäristössä. Dynaaminen toimintaympäristö asettaa vaatimuksia luottamuksenhallintajärjestelmälle, jota käytetään paitsi paikallisten pääsynhallintapäätösten tekemiseen, myös laajemman mittakaavan päätöksenteon tukena, useiden autonomisten toimijoiden muodostamien yhteisöjen hallinnassa. Tutkielma esittelee Trust Based on Evidence -projektissa kehitetyn luottamuksenhallintajärjestelmän tiedollisen ja toiminnallisen mallin, paikallisesta ja yhteisön näkökulmasta. Mallia selkeytetään web-palveluympäristöön sijoittuvan esimerkin avulla. Luottamuksen käsitteen rakentamiseksi esitellään myös eri osa-alueille sijoittuvia luottamuksen malleja ja luottamusta käyttäviä järjestelmiä. Avoimessa verkkoympäristössä palveluntarjoaja joutuu tasapainottelemaan kahden osin vastakkaisen tavoitteen välillä: toisaalta järjestelmän tulisi olla mahdollisimman avoin, jotta se houkuttelisi käyttäjiä, toisaalta liiallinen avoimuus kasvattaa tietomurron riskiä. Kompromissin löytäminen on hankaloitunut edelleen saavutettavien käyttäjien määrän kasvaessa ja tarjottavien palvelujen monimutkaistuessa. Tehtävä vaatii toisaalta erikoistapauksien käsittelyä, toisaalta yleistettävyyttä laajan käyttäjistön suhteen. Tietoturvan ylläpidon automatisointia ovat edistäneet muun muassa politiikkapäätösten erottaminen toteutuksesta ja mahdollisten tietomurron merkkien tarkkailun delegointi siihen erikoistuneille ohjelmille (IDS). Palvelujen käyttäjistön kasvaessa ja siirtyessä nimettömämmiksi kurinpito ja tarkkailu kuitenkin vaikeutuvat entisestään, eikä ylläpitäjiä riitä sidottavaksi jatkuvaan käyttäjien vahtimiseen. Monesti valvoja voikin vain poistaa käyttöoikeuden häiriköltä, jolloin esimerkiksi hieman lievemmälle sääntöjen 'venyttämiselle'' ei juuri voi tehdä mitään. Luottamuksenhallinta helpottaa rikkomuksiin ja toisaalta hyvään käytökseen reagoimista asteittain. Sen pohjalta käyttäjien valvontaan, pääsynhallintaan ja resurssien rajoitukseen liittyvä hienosäätö voidaan tuoda ymmärrettäväksi osaksi ylläpitoa ja pitkälti myös automatisoida

Similarity-based Techniques for Trust Management

A network of people having established trust relations and a model for propagation of related trust scores are fundamental building blocks in many of todayŠs most successful e-commerce and recommendation systems. Many online communities are only successful if sufficient mu-tual trust between their members exists. Users want to know whom to trust and how muc

SecMon: End-to-End Quality and Security Monitoring System

The Voice over Internet Protocol (VoIP) is becoming a more available and popular way of communicating for Internet users. This also applies to Peer-to-Peer (P2P) systems and merging these two have already proven to be successful (e.g. Skype). Even the existing standards of VoIP provide an assurance of security and Quality of Service (QoS), however, these features are usually optional and supported by limited number of implementations. As a result, the lack of mandatory and widely applicable QoS and security guaranties makes the contemporary VoIP systems vulnerable to attacks and network disturbances. In this paper we are facing these issues and propose the SecMon system, which simultaneously provides a lightweight security mechanism and improves quality parameters of the call. SecMon is intended specially for VoIP service over P2P networks and its main advantage is that it provides authentication, data integrity services, adaptive QoS and (D)DoS attack detection. Moreover, the SecMon approach represents a low-bandwidth consumption solution that is transparent to the users and possesses a self-organizing capability. The above-mentioned features are accomplished mainly by utilizing two information hiding techniques: digital audio watermarking and network steganography. These techniques are used to create covert channels that serve as transport channels for lightweight QoS measurement's results. Furthermore, these metrics are aggregated in a reputation system that enables best route path selection in the P2P network. The reputation system helps also to mitigate (D)DoS attacks, maximize performance and increase transmission efficiency in the network.Comment: Paper was presented at 7th international conference IBIZA 2008: On Computer Science - Research And Applications, Poland, Kazimierz Dolny 31.01-2.02 2008; 14 pages, 5 figure

From subjective reputation to verifiable experiences - augmenting peer-control mechanisms for open service ecosystems

Peer reviewe

Towards a Conceptualisation of Trust in IS Outsourcing

Despite the implicit recognition of trust in IS outsourcing, comparatively few research could be found in this area. While addressing the nature of trust in IS outsourcing, we found surprisingly many aspects on the concept of trust which have not been captured in the mainstream research on IS outsourcing. This paper presents an interdisciplinary view on trust and attempts to call for a greater understanding and focus on the role and impact of trust in an outsourcing context. It is argued that trust does play a significant role in many aspects of IS outsourcing and potentially could be one of the key elements that contributes to the success of an outsourcing activity. The paper suggests a multidimensional approach to the exploration of trust in outsourcing relationships with a greater focus on multi-faceted aspects of trust as well as the mediating factors that influence the success and/or failure of IS outsourcing activities

Arguing Security: A Framework for Analyzing Security Requirements

When considering the security of a system, the analyst must simultaneously work with two types of properties: those that can be shown to be true, and those that must be argued as being true. The first consists of properties that can be demonstrated conclusively, such as the type of encryption in use or the existence of an authentication scheme. The second consists of things that cannot be so demonstrated but must be considered true for a system to be secure, such as the trustworthiness of a public key infrastructure or the willingness of people to keep their passwords secure. The choices represented by the second case are called trust assumptions, and the analyst should supply arguments explaining why the trust assumptions are valid. This thesis presents three novel contributions: a framework for security requirements elicitation and analysis, based upon the construction of a context for the system; an explicit place and role for trust assumptions in security requirements; and structured satisfaction arguments to validate that a system can satisfy the security requirements. The system context is described using a problem-centered notation, then is validated against the security requirements through construction of a satisfaction argument. The satisfaction argument is in two parts: a formal argument that the system can meet its security requirements, and structured informal arguments supporting the assumptions exposed during argument construction. If one cannot construct a convincing argument, designers are asked to provide design information to resolve the problems and another pass is made through the framework to verify that the proposed solution satisfies the requirements. Alternatively, stakeholders are asked to modify the goals for the system so that the problems can be resolved or avoided. The contributions are evaluated by using the framework to do a security requirements analysis within an air traffic control technology evaluation project

The WebID Protocol Enhanced With Group Access, Biometrics, and Access Policies

The WebID protocol solves the challenge of remembering usernames and passwords. We enhance this protocol in three ways. First, we give it the ability to manage groups of agents and control their access to resources on the Web. Second, we add support for biometric access control to enhance security. Finally, we add support for OWL-based policies that may be federated and result in flexible access control

SecMon: end-to-end quality and security monitoring system

The Voice over Internet Protocol (VoIP) is becoming a more available and popular way of communication for the Internet users. This also applies to the Peer-to-Peer (P2P) systems and merging these two have already proven to be successful (e.g. Skype). Even the existing standards of VoIP provide an assurance of security and Quality of Service (QoS), however, these features are usually optional and supported by a limited number of implementations. As a result, the lack of mandatory and widely applicable QoS and security guarantee makes the contemporary VoIP systems vulnerable to attacks and network disturbances. In this paper we are facing these issues and propose the SecMon system, which simultaneously provides a lightweight security mechanism and improves quality parameters of the call. SecMon is intended specially for VoIP service over P2P networks and its main advantage is that it provides authentication, data integrity services, adaptive QoS and (D)DoS attack detection. Moreover, the SecMon approach represents a lowbandwidth consumption solution that is transparent to the users and possesses a self-organizing capability. The above-mentioned features are accomplished mainly by utilizing two information hiding techniques: digital audio watermarking and network steganography. These techniques are used to create covert channels that serve as transport channels for lightweight QoS measurement results. Furthermore, these metrics are aggregated in a reputation system that enables best route path selection in the P2P network. The reputation system helps also to mitigate (D)DoS attacks, maximize performance and increase transmission efficiency in the network