Trusted third party

About: Trusted third party is a research topic. Over the lifetime, 2919 publications have been published within this topic receiving 60935 citations.

Smart Contracts for Spectrum Sensing as a Service

Abstract: Mobile network operators (MNO) can opportunistically use the licensed bands of the primary users (PU) provided that they monitor the spectrum and stop their transmission upon detection of the PU. As deploying spectrum sensors may be prohibitively expensive, the MNO can buy spectrum sensing service from sensing helpers in its proximity. However, such a trade requires a framework with three key functions: helper selection, faulty or malicious helper identification, and payment to honest helpers. Here, we introduce Spass which provides these functions and facilitates a fair exchange between the entities without a trusted third party via smart contracts (SC) running on a blockchain network. While payments via SCs seem conceptually simple, realizing it is difficult due to the cost of using SC functions which might be prohibitive as write/computation operations on the SCs might have a cost, e.g., in Ethereum. Considering our design goals and SC-related overhead, we derive the optimal Spass parameters maximizing the MNO’s profit. Moreover, we propose a K-means clustering approach to identify independent malicious helpers, and using both lossless and lossy compression on the helpers’ sensing report to decrease the cost of write operations. Via simulations, we show under which conditions Spass-powered service leads to a profitable business for an MNO.

Dynamic Decentralized Functional Encryption

Abstract: We introduce Dynamic Decentralized Functional Encryption (\(\textsf {DDFE}\)), a generalization of Functional Encryption which allows multiple users to join the system dynamically, without relying on a trusted third party or on expensive and interactive Multi-Party Computation protocols.

Method and apparatus for a secure communications session with a remote system via an access-controlling intermediate system

Abstract: A security protocol entity ( 20 ) is provided that includes a mechanism for enabling a first party ( 11 ) to communicate securely with a second party ( 60 ) through an access-controlling intermediate party ( 13 ) by nesting within a first security session ( 64 ) established with the intermediate party ( 13 ) a second security session ( 65 ) with the second party ( 60 ). The protocol data units, PDUs, associated with the second security session ( 65 ) are encapsulated in PDUs associated with the first security session ( 64 ) when sent out by the first party, the intermediate party extracting the encapsulated PDUs for sending on to the second party (possibly with a change to the destination address included in the PDU to be sent on). Each PDU includes a message type field explicitly indicating to the intermediate party ( 13 ) if a received PDU encapsulates another PDU intended to be sent on. The establishment of a security session between two parties is made dependent on each party proving by attribute certificates that it has certain attributes required of it by the other party. Where the intermediate party ( 13 ) fronts for the second party ( 60 ) and the first party ( 11 ) initially contacts the intermediate party in the belief that it is the second party, then the latter will indicate its relay status to the first party which can then request the intermediate party ( 13 ) to permit a tunnel to be established through it to the second party ( 60 ). The first party may place different attribute requirements on the intermediate party in its tunnel role to those initially expected of it when the first party thought it was the second party.

Towards a human trust model for mobile ad-hoc networks

Abstract: Rapid advances in wireless networking technologies have enabled mobile devices to be connected anywhere and anytime. While roaming, applications on these devices dynamically discover hosts and services with whom interactions can be started. However, the fear of exposure to risky transactions with unknown entities may seriously hinder collaboration. In order to advance the goal of anywhere-anytime computing, the exposure to risky transactions has to be reduced as much as possible. This requires the existence of a trust management framework that enables devices to form, maintain and exchange trust opinions. These opinions can then be used to customise the way interactions take place: for example, to decide from where to download a file, what service provider to contact, what access rights to grant, and so on. Trust is obviously not the only aspect that must be taken into account when making these decisions: the perceived risk inherent to a transaction, and the quality of service (QoS) requirements will all contribute to the final configuration decisions. However, feelings of trust, risk and QoS can be formed independently of each other, and thus dealt with separately, before being combined. At present, we are concerned with trust management issues only. A trust decision framework for mobile ad-hoc networks must be fully decentralised, as we cannot assume the existence of a trusted third party that can be contacted on demand to acquire reputation information about an entity. Approaches such as [4] cannot therefore be applied to the mobile setting, as they assume the existence of a central specification server where trust information is stored and used. The framework must be highly customisable, in order to capture the varying and complex natural disposition of an individual to trust into computer models; this should be achieved without causing disruption to the device computation and communication resources. Approaches such as [2] work well at the routing level, where trust decisions are automatic and homogeneous, but suffer severe limitations at the application level, where subjectivity in the decision making process becomes fundamental. Other approaches (e.g., [5]) deal with trust in a less automatic fashion, but they still fail to capture a variety of aspects peculiar to human trust (e.g., ways to recover from a bad reputation, natural disposition to trust unknown entities, etc.). Finally, a trust decision framework for mobile ad-hoc networks must be selfish: in a resource constrained environment, selfishness is likely to prevail over cooperation, for example, to save battery power. A trust management framework cannot therefore completely rely on the assumption that entities have a social conscience that will make them exchange reputation information whenever asked. This limits the applicability of approaches such as [1]. We are currently designing and formalising a trust management framework that meets these requirements. Our approach is completely decentralised: each entity acts as a self-contained unit, carrying along a portfolio of credentials derived from the past interactions of the entity, and that the entity uses to prove its trustworthiness to others. This portfolio is created and maintained during peer interactions, and can be used as the unique source of reputation information when having to make a trust decision, in case the social context is populated by a majority of selfish agents that are not willing to propagate reputation information. Finally, our model makes intensive use of customisable functions to adapt the behaviour of the trust management framework according to the agent’s disposition, thus capturing human models of trust in computer models. Altogether, these functions enable the model to semi-automatically derive new trust relationships from previously formed ones. In the following section, we provide a more detailed description of the major characteristics of this trust management framework.

Dynamic, interactive call notification

Abstract: A system and method that provides a dialog with the called party when a call is received, a process is initiated to communicate with the calling party and a process is initiated to communicate with the called party. The processes communicate with each other to provide limited communication between the called and calling parties without an actual connection being made between them. The called party process determines disposition of the call based on the caller ID of the calling party and the state of the called party telephone. Advantageously, the called party process prompts the called party as to how to handle the call. The called party can request further information regarding the person calling, the purpose of the call, etc., without a connection being made to the calling party.