EVALUATING SYSTEM SECURITY USING TRANSACTION LEVEL MODELLING

The design of secure systems requires the use of security analysis techniques. Security objectives have to be considered during the early stages of system development and design; an executable model will give the designer the adventage of exploring the vulnerabilities early, and therefore enhancing the system security. In this work we create an executable model of a smart card system using SystemC with the Transaction Level Modelling (TLM) extensions. The model includes the security protocols and transactions. The model is used to compare a number of authentication mechanisms with different probabilities of failure. In addition, a number of probable attacks, including theft of a private key and denial of service were modelled to examine the vulnerabilities. The executable model shows that security protocols and transactions can be effectively simulated in order to design improvements to withstand different types of security attacks     

Group key establishment protocols: Pairing cryptography and verifiable secret sharing scheme

Thesis (Master)--Izmir Institute of Technology, Computer Engineering, Izmir, 2013Includes bibliographical references (leaves: 97-103)Text in English; Abstract: Turkish and Englishx, 154 leavesThe 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