Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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2007 - 200912010 - 20131

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Subject: search.filters.subject.Data encryption (Computer science)

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  • Master Thesis
    The Comparative Performance Analysis of Lattice Based Ntru Cryptosystem With Other Asymmetrical Cryptosystems
    (Izmir Institute of Technology, 2007) Mersin, Ali; Koltuksuz, Ahmet Hasan
    Current popular asymmetrical cryptosystems are based on hardness of number theoretic problems. In the future, these problems may become practically solvable with the improvements of processing power, the development of quantum computation and distributed computation. So the need for new cryptosystems which are not based on these problems has risen. Researches on hardness of lattice problems have brought a new candidate for asymmetrical cryptography: Lattice Based Cryptography. NTRU is one of these cryptosystems. For practical use, the actual performance results of NTRU with respect to current asymmetrical cryptosystems should be known. This thesis is developed based on this purpose.
  • Master Thesis
    Group Key Establishment Protocols: Pairing Cryptography and Verifiable Secret Sharing Scheme
    (Izmir Institute of Technology, 2013) Aslanoğlu, Rabia; Şahin, Serap
    The aim of this study is to establish a common secret key over an open network for a group of user to be used then symmetrical secure communication between them. There are two methods of GKE protocol which are key agreement and key distribution. Key agreement is a mechanism whereby the parties jointly establish a common secret. As to key distribution, it is a mechanism whereby one of the parties creates or obtains a secret value and then securely distributes it to other parties. In this study, both methods is applied and analyzed in two different GKE protocols. Desirable properties of a GKE are security and efficiency. Security is attributed in terms of preventing attacks against passive and active adversary. Efficiency is quantified in terms of computation, communication and round complexity. When constructing a GKE, the challenge is to provide security and efficiency according to attributed and quantified terms. Two main cryptographic tools are selected in order to handle the defined challenge. One of them is bilinear pairing which is based on elliptic curve cryptography and another is verifiable secret sharing which is based on multiparty computation. In this thesis, constructions of these two GKE protocols are studied along with their communication models, security and efficiency analysis. Also, an implementation of four-user group size is developed utilizing PBC, GMP and OpenSSL Libraries for both two protocols.