2012 Tenth Annual International Conference on Privacy, Security and Trust 978-1-4673-2326-0/12/$31.00 ©2012 IEEE 153 A concordance framework for building trust evidences Anirban Basu *† , Natasha Dwyer ‡ and Stephen Naicken † * Graduate School of Engineering, Tokai University, 2-3-23 Takanawa, Minato-ku, Tokyo 108-8619, Japan abasu@cs.dm.u-tokai.ac.jp † Department of Informatics, University of Sussex, Brighton BN1 9QJ, UK {a.basu,stephenn}@sussex.ac.uk ‡ Victoria University, Footscray Park Campus, Ballarat Road, Footscray, 3011, Australia natasha.dwyer@vu.edu.au Abstract—Online dating is one domain, which would benefit from the application of computational trust. One of the problems with the application of traditional computational trust models, as identified in our previous work, is authenticity of information provided by parties which helps other users ascertain whether they want to go on dates. In this position paper, we suggest a solution: a concordance based framework for a game to be built into a online dating system. The game provokes users to provide spontaneous and thus more genuine data about themselves. The key feature of the game is the respect for privacy that supports and encourages the user to provide authentic information. Future work will comprise of implementation of the game and its user testing. Index Terms—computational trust, emotive application, trust evidence, game I. I NTRODUCTION One of the key problems of any trust model, particularly in a highly emotive context, is with the lack of truthfulness on the part of the user in the “information gathering” stage [1]. In the domain of online dating, some respondents purposefully lie in their profiles in attempts to attract potential dates. However, trustors seek genuine information about others because this gives an indication of what a person is ‘really’ like, that is the data has not been filtered [2]. In this position paper, we propose a framework of a game for users to play which helps assess whether two parties are broadly in agreement, i.e., concordant about certain opinions or not. The aim is not for users to build trust but rather to assess whether they might trust other users with certain qualities. Fukuyama [3] argues that we have more trust in those who share our values. Rather than our trust-based decisions being motivated by pure self-interest, our decisions are shaped by the belief that people with similar values to our own will be interested in a positive outcome for the group with whom they identify [4]. At the core of the proposed framework is the posing of questions that provokes respondents to provide more truthful answers that others can use to build an authentic trust assessment. As the user needs to respond quickly to the questions, the user is likely to provide information spon- taneously without the opportunity to contrive answers. The game can help an online dating system, amongst many other application scenarios, to build more authentic trust evidence displays for potential dating partners. While anonymised and non-persistent player identities constitute a privacy-respecting step, pseudonymous but persistent identities [5] can be used to detect liars while not compromising privacy. To encourage users to answer as authentically as possible, the game is in real time. Users do not have the time to contrive their answers. The spontaneous nature of the game is intended to capture an authentic measure of concordance. II. A FRAMEWORK FOR CONCORDANCE A. Gameplay The principles of the game are as follows: (I) At the start of the game, a player is asked to choose a partner from a list of active users (i.e., other players). If the choice is accepted, the game starts. (II) In each level, a player is asked to answer a set of questions on a numeric scale, e.g., from 1 to 10, within a time limit. The question itself is subtle and levels are used to group questions belonging to the same general topic. (III) In essence, questions can also be set by users themselves but before being posed to users, these ought to meet certain criteria: subtlety, respect for privacy and so on. (IV) Privacy is respected by not storing user data; by not allowing questions that can form the basis of inference-based attacks. This gives the participants the confidence to provide truthful answers, especially around sensitive topics. The players are also not required to answer any question that they do not wish to. (V) Concordant and discordant answers are calculated for each level between a pair of players. Players may choose to continue to the next level with the same partner, or select a different partner. (VI) At the end of the game, a player gets a good idea about how similar or dissimilar other players are in various contexts (i.e., levels). This helps two potential dates embark on a more direct form of meaningful interaction 1 . B. Measures of concordance Given two players A and B, and the centrality measures for their answers as c A and c B respectively, the parties are said to be concordant on their opinions (o k,A and o k,B for 1 Note that for safety reasons, offline communication may be preceded by third-party verification processes, which are beyond the scope of this paper.