Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis A Turkish Password Cracker for Unix Based Operating Systems(Izmir Institute of Technology, 2001) Tahaoğlu, Osman Okyar; Koltuksuz, Ahmet; Koltuksuz, Ahmet HasanUNIX and UNIX-based operating systems have been widely utilized in local area and wide area network systems that supply application and development chain of users through remote access as well as online connections. Although UNIX operating system has got powerful tools which have secure methods for user authentication, user management and for password storage, weak password choices of the users affect the entire system security negatively. This study aims to crack the password hashes which are encrypted by DES using the method of dictionary attack. The developed application is introduced and compared with the previous utilities. Password encryption, password storage, and the structure which was developed against a possible dictionary attack of UNIX are examined. The good password choosing method for the users and the system administrator are given.Master Thesis An Analysis of Key Generation Efficiency of Rsa Cryptosystem in Distributed Environments(Izmir Institute of Technology, 2005) Çağrıcı, Gökhan; Koltuksuz, Ahmet; Koltuksuz, Ahmet HasanAs the size of the communication through networks and especially through Internet grew, there became a huge need for securing these connections. The symmetric and asymmetric cryptosystems formed a good complementary approach for providing this security. While the asymmetric cryptosystems were a perfect solution for the distribution of the keys used by the communicating parties, they were very slow for the actual encryption and decryption of the data flowing between them. Therefore, the symmetric cryptosystems perfectly filled this space and were used for the encryption and decryption process once the session keys had been exchanged securely. Parallelism is a hot research topic area in many different fields and being used to deal with problems whose solutions take a considerable amount of time. Cryptography is no exception and, computer scientists have discovered that parallelism could certainly be used for making the algorithms for asymmetric cryptosystems go faster and the experimental results have shown a good promise so far. This thesis is based on the parallelization of a famous public-key algorithm, namely RSA.