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    Cryptanalysis of Stream Ciphers By Structural Attacks

    , M.Sc. Thesis Sharif University of Technology Rohani, Neda (Author) ; Aref, Mohammad Reza (Supervisor) ; Mohajeri, Javad (Supervisor)
    Abstract
    According to the development of communication, cryptography has become a vital issue. Several algorithms have been introduced for cryptography applications. Stream ciphers are such algorithms with high speed and appropriate efficiency. Lots of attacks have been applied to stream ciphers. We concentrate on two kinds of attacks in this thesis. Distinguishing attack is a general attack in which the attacker tries to distinguish the observed output sequence from random. Designers apply this kind of attack to test the statistical probabilities of the output sequence. We applied this attack on Grain family and Trivium family. In the proposed attack, nonlinear parts are replaced with linear ones.... 

    Design of FPGA Cluster Platform For Cryptanalysis Applications

    , M.Sc. Thesis Sharif University of Technology Hosseini, Hamid Reza (Author) ; Jahangir, Amir Hossein (Supervisor)
    Abstract
    Daily improvements in technology and exchanging important information via internet and connection networks make data and connection security a significant problem. Cryptology is the branch of knowledge which concerns secret communications in all of its aspects. Two major areas of cryptology are cryptography and cryptanalysis. Cryptography is a branch of cryptology concerned with protecting communications from being read by unauthorized people.
    Cryptologists design and create algorithms to improve cryptography along with finding methods to crack those algorithms. Cryptanalysis is a branch of cryptology concerned with cracking the cryptographic systems used by others.
    Cryptographic... 

    Reconfigurable Architecture For Cryptanalysis Applications

    , M.Sc. Thesis Sharif University of Technology Noshadravan, Mohammad Reza (Author) ; Jahangir, Amir Hossein (Supervisor)
    Abstract
    Nowadays, the significance of securing data and information is undeniable. Cryptography is being used to provide data security. In addition, cryptanalysis is required to evaluate the effectiveness of cryptography methods, and hence, it is an essential concept for securing data. In general, the cryptography functions shall be designed in a way to impose a high load of time-intensive operations to prevent an adversary from accessing the main data from the encrypted data. As a result, cryptography and cryptanalysis algorithms need high performance computations. So far, a number of methods have been proposed to support the required performance. These methods include: distributed computing and... 

    Security Analysis of an Offline Mobile Micro-Payment System

    , M.Sc. Thesis Sharif University of Technology Foroutan, Fouzhan (Author) ; Goudarzi, Maziar (Supervisor)
    Abstract
    Mobile payment has already become an integral part of modern life for daily banking needs. Many payment systems are now providing financial services to customers. Most of these systems need and rely on online network access to provide their services. On the other hand, there are many regions in the world that have no network access or the network quality is poor with intermittent failures. Customers in these areas are unable to transfer money or buy goods and pay for it using their mobile devices by such above systems. This motivated us to find a way for transferring money without need for network availability. As a result we devised an offline peer-to peer mobile payment system (MobiPOS).... 

    Cryptanalysis of Lightweight Primitives and Protocols

    , Ph.D. Dissertation Sharif University of Technology Ahmadian, Zahra (Author) ; Salmasizadeh, Mahmood (Supervisor) ; Aref, Mohammad Reza (Supervisor)
    Abstract
    Lightweight cryptography is a new area in cryptography developed as a solution to the security requirements in pervasive, low cost and lightweight systems, such as RFID networks. Due to the pervasive nature of these systems, the users’ privacy is seriously threatened while severe restrictions are imposed on computational, memory and power resources. Therefore, the conventional design rules of cryptographic primitives and protocols are not accountable here and the designers have adopted innovative methods for lightweight designs. This makes the design of a lightweight primitive/protocol a very challenging and sensitive task which is not still reliable enough. Such a trust can not be made... 

    A Primer to Bayesian Methods in Cryptanalysis

    , M.Sc. Thesis Sharif University of Technology Nokhbeh Zaeem, Mohammad (Author) ; Daneshgar, Amir (Supervisor)
    Abstract
    In this thesis, based on the model introduced in [Murphy et. al., Likelihood Estimation for Block Cipher Keys, 1995], we discuss the possibility of unifying the cryptanalysis methods. First, the model for cryptanalysis is discussed and explained by modelling several known statistical attack. In the end, using this model, we propose attacks more general than linear and differential methods  

    Cryptanalysis of Lightweight Block Ciphers

    , M.Sc. Thesis Sharif University of Technology Rasoulzadeh, Shahram (Author) ; Aref, Mohammad Reza (Supervisor) ; Salmasizadeh, Mahmoud (Co-Advisor)
    Abstract
    Lightweight cryptography is a branch of cryptography science which is expanded in response of security need in pervasive and lightweight systems (such as RFID systems and wireless sensor networks) in the last decade. In general, the significant challenges in designing lightweight ciphers can be attributed to three essential parameters: security, cost, and performance. Hence the main goal in designing new lightweight ciphers is to develop innovative and atypical structures in order to have a cipher with a small footprint, sufficient speed, reduced power consumption, while remaining sufficiently secure. Due to lack of proper ciphers that are both efficient and secure for constrained... 

    Security analysis and confidentiality in the Internet of Things

    , M.Sc. Thesis Sharif University of Technology Zare Jousheghani, Zahra (Author) ; Aref, Mohammad Reza (Supervisor)
    Abstract
    Nowadays, Internet of Things is considered as a global infrastructure to establish communication between physical world and virtual world by using existing technologies. Its purpose is enabling things to establish communication with anything and any person in any time and any place by using existing networks and services. This technology makes different aspects of people's life smarter, facilitates doing works, and increases the quality of people's life. But, the development of Internet of Things faces to fundamental challenges that one of the most important of them is security and privacy preserving of users. According to the projects of European Research Cluster on the Internet of Things...