Mehrdad Nojoumian

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This paper aims at the trust calculation in social networks by addressing some major issues: Firstly, the paper evaluates a specific trust function and its behaviors, and then it focuses on the modification of that trust function by considering diverse scenarios. After that, the paper proposes a new approach with a specific functionality. The main goals are(More)
We introduce the notion of a Social Secret Sharing Scheme, in which shares are allocated based on a player's reputation and the way he interacts with other participants. During the social tuning phase, weights of players are adjusted such that participants who cooperate will end up with more shares than those who defect. Alternatively, newcomers are able to(More)
Due to the rapid growth of e-commerce technology, secure auction protocols have attracted much attention among researchers. The main reason for constructing sealed-bid auction protocols is the fact that losing bids can be used in future auctions and negotiations if they are not kept private. Our motivation is to develop a new commitment scheme to construct(More)
The research presented in this paper aims at facilitating the creation of knowledge bases (KBs) for software specifications, of which the UML superstructure specification is our initial target. Our motivation is that such specifications are dense, repetitive and difficult to use. They are written primarily in semi-structured text, but the structure must be(More)
This article proposes efficient solutions for the construction of sealed-bid second-price and combinatorial auction protocols in an active adversary setting. The main reason for constructing secure auction protocols is that the losing bids can be used in the future auctions as well as negotiations if they are not kept private. Our motivation is to apply(More)
Rational secret sharing was proposed by Halpern and Teague in [12]. The authors show that, in a setting with rational players, secret sharing and multiparty computation are only possible if the actual secret reconstruction round remains unknown to the players. All the subsequent works use a similar approach with different assumptions. We change the(More)
In a threshold scheme, the sensitivity of the secret as well as the number of players may fluctuate due to various reasons, e.g., mutual trust may vary or the structure of the players' organization might be changed. A possible solution to this problem is to modify the threshold and/or change the secret. Moreover, a common problem with almost all secret(More)
—We first review the notion of social secret sharing and its trust function. We then illustrate how this construction can be used in cloud computing to create a self-organizing environment. In fact, we show distributed secure systems using threshold secret sharing can be adjusted automatically based on the resource availability of the cloud providers.(More)
Designing a sealed-bid auction protocol is a challenging problem in the field of applied cryptography. In the last couple of decades, numerous protocols have been proposed in the literature where each one has its own property in terms of the security model, communication and computation complexities. To the best of our knowledge, there has been no study to(More)