Sharif Digital Repository

In the secure data outsourcing scenario, verification of the reply of an unreliable server includes assessing the authenticity, completeness and it’s integrity. In this thesis, an efficient method, with emphasis on freshness, has been introduced to evaluate the correctness of the replies from a server. It takes in hand different application needs, inherent differences in the data, and different update mechanisms. This method evaluates freshness by using timestamps alongside the data being out sourced. Due to the requirement of verifying not only the freshness of the response, but the correctness of the timestamps as well, two general methods for evaluating and verifying the responses were... 

IF Logic is an extension of First-Order logic, including syntactic connective ’/’ (independence indicator) which carries the concept of ’independent from’ in language and metalanguage.This logic which has introduced by Hintikka and Sandu in 1989, uses Game-theoretical semantics (GTS) such that every formula is defined as a game and the players are verifier and falsifier of its truth. The formula is True if the verifier has a winning-strategy and it is False where the falsifier has a winning-strategy; and evaluated as indeterminate otherwise. this relates a central concept of logic (truth) to a central concept of game theory(winningstrategy)  

One of the security issues in database outsourcing scenario is the correctness of the query results. Correctness verification includes integrity, completeness and freshness of the results. Most of the proposed approaches for correctness verification impose high overhead on the components of the scenario which prevents the scenario to implemented in practical applications. In this thesis, we have proposed a probabilistic approach which imposes acceptable overhead for correctness verification of returned results of service provider. The approach uses the previous behavior of the service provider to calculate a trust value toward it which is used to adjust the imposed overhead. In other words,...