M Tech Dissertations

Permanent URI for this collectionhttp://ir.daiict.ac.in/handle/123456789/3

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Subject: search.filters.subject.Computer program language

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Now showing 1 - 4 of 4
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    ItemOpen Access
    Schema based indexing for namespace mapping of raw sparql and summarization of lod
    (Dhirubhai Ambani Institute of Information and Communication Technology, 2015) Hapani, Hitesh; Jat, P. M.
    Linked open data(LOD) in Semantic Web is growing day by day. There are datasets available that can be used in different application. However, identifying useful dataset from cloud, determining the quality and obtaining inductive information from dataset are all tasks that require to be addressed. The more traffic on LOD increases, the more difficult it will become to identify useful dataset. The reason behind this problem is that there is no useful summary available about datasets. While querying any dataset through endpoint, The most cumbersome part is remembering URIs for resources. There is no known interface that provides URIs for the user terms. There are some standard available for providing summary and metadata about datasets. But till now no standard is available that is universally accepted. Index structure proposed in this thesis gives a schema level information about any dataset and provides URI information for dataset. This index structure has been successfully implemented on local dataset server and remote dataset server in this thesis.
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    ItemOpen Access
    Secure SQL with access control for database as a service model
    (Dhirubhai Ambani Institute of Information and Communication Technology, 2014) Dave, Jay; Das, Manik Lal
    Rapid growth of internet and networking technology emerges "Software as a service model". In this model, application service providers (ASP) provides each functionality of software over internet. ASP provides access of software to users on internet. However, large data of a great number of users may raise problem of storage at ASP site. Database as a service model is more appropriate model for ASPs. This model allows all privileges of database to its users over internet. ASPs can store their large data on database provider. Database provider serves each functionality of database over network. However, this model raises problems of confidentiality of data. Confidential data of users are stored at untrusted database provider. Theft of sensitive data is possible at database provider site. An outside attacker can attack on database provider and snoops confidential data. Curious or malicious database administrator can also steal sensitive data. We studied present encryption schemes which provide confidentiality to database as a service model. First we studied scheme of Hakan, et al.[6], which provides security by storing encrypted form of whole tuple in database. However, this scheme results more computation at ASP site. Second scheme, CryptDB[7] does not have this problem. CryptDB provides security by encrypting data with different encryption methods. However, this scheme removes randomness of such cipher texts which do not need randomness removal. This issue results equality relation leakage and order relation leakage of cipher texts. We focused on solving these limitations and providing more secure scheme. We proposed solution to limitations of CryptDB. For that, ASP partitions attributes and encrypts each partition with different key. This solution makes sure by removing randomness from appropriate partition which contains such cipher texts (which need randomness removal). Cipher texts of other partition are secured with randomness. We elaborated all schemes with examples. We listed analysis of proposed solution to issue of CryptDB. We gave security proofs for our proposed solution. We also implemented a module of this scheme.
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    Prolog based approach to reasoning about dynamic hierarchical key assignment schemes
    (Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Mundra, Anil Kumar; Mathuria, Anish M.
    The problem of allowing the higher level users access the information related to lower level is called Hierarchical Access Control Problem. In a hierarchical access control system, users are partitioned into a number of classes - called security classes, which are organized in a hierarchy. Hierarchies arise in systems where some users have higher privileges than others and a security class inherits the privileges of its descendant classes. A basic Hierarchical Key Assignment Scheme is a method of assigning an encryption key to each class in the hierarchy. In literature, there are number of such hierarchy schemes are available and many of them have formal proof models for security properties. Now a days mostly all the schemes have a solution for Dynamic Access Control problem. We found that for dynamic schemes no formal proof model is available so we can not make any arguments on security properties of such schemes. We present a new approach for automatic veri cation using Prolog for the analysis of existing dynamic and static hierarchical key assignment schemes and verify their security properties. We discover some new attacks on existing schemes and proposed a new scheme to overcome those attacks.
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    ItemOpen Access
    Performance evaluation of kerberos cross-realm authentication using SIMNET
    (Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Sethi, Ankit Kumar; Mathuria, Anish M.
    Today, the network is being implemented in such a manner that consist of geographi- cally diverse clients and distributed as well as centralized servers. To prevent unauthorized access to system resources such as servers, authentication is required. Kerberos is a trusted third party network authentication protocol which securely authenticates the users over insecure communication channel. Due to change in requirements and better utilization of resources, the client and server may reside across organizational boundary. To access such resources, a user has to authenticate itself. Cross-realm authentication is such a technique which facilitates authentication across the realms. In Cross-realm authentication, initially a user has to authenticate to it local Authentication Server (AS) and get the credentials. Acquired credentials are used to authenticate the user to the application server which resides over destination realm. Crescenzo and Kornievskaia designed an e cient protocol for cross-realm authentica- tion that decreases communication over the internet. They considered an extension to the original Kerberos protocol that enables cross-realm operations, identi ed its ine ciencies and proposed an alternative protocol called Fake Ticket Protocol (FTP). In FTP, local AS generates a ticket for the user to access the application server in destination realm and instead of sending it to destination AS, it is forwarded to the application server directly by user. Because application server cannot determine the legitimacy of ticket, it was named as Fake Ticket and so the protocol as Fake Ticket Protocol. Simnet is a network simulator which provides the functionality to simulate network security protocols. Using Simnet, we implemented Kerberos and FTP with their full capabilities. The aim of this thesis is to do the performance evaluation of the kerberos protocol vi and Fake Ticket Protocol for the Cross-Realm approach using Simnet. The simulation results show that in the scenario where a client repeatedly authen ticates to a stateless server using the same ticket, the original Kerberos cross-realm protocol performs better than FTP. In the case that the client authenticates to the server only once, FTP does better.