جواد مهاجری
پژوهشکده الکترونیک، دانشگاه صنعتی شریف
[ 1 ] - حمله‌ی تمایز بر نوع ساده‌شده‌ی رمز دنباله‌یی 128- WG
الگوریتم رمز دنباله‌یی (Welch - Gong) WG، یک الگوریتم رمز با کلیدی با طول متغیر ۸۰، ۹۶، ۱۱۲ و ۱۲۸ بیت است که با هدف شرکت در گروه ۲ پروژه‌ی eSTREAM طراحی شده است. در این نوشتار به تحلیل الگوریتم رمز دنباله‌یی 128- WG، و بررسی میزان مقاومت آن دربرابر حمله‌ی تمایز مبتنی بر تقریب خطی پرداخته‌ایم. با یافتن یک نقاب خطی مناسب برای بخش غیرخطی 128- WG، حمله‌ی تمایز به الگوریتم- ساده‌شده )بدون در نظر گ...
[ 3 ] - حمله‌ی تمایز بر نوع ساده‌شده‌ی رمز دنباله‌یی 128- WG
الگوریتم رمز دنباله‌یی (Welch - Gong) WG، یک الگوریتم رمز با کلیدی با طول متغیر ۸۰، ۹۶، ۱۱۲ و ۱۲۸ بیت است که با هدف شرکت در گروه ۲ پروژه‌ی eSTREAM طراحی شده است. در این نوشتار به تحلیل الگوریتم رمز دنباله‌یی 128- WG، و بررسی میزان مقاومت آن دربرابر حمله‌ی تمایز مبتنی بر تقریب خطی پرداخته‌ایم. با یافتن یک نقاب خطی مناسب برای بخش غیرخطی 128- WG، حمله‌ی تمایز به الگوریتم- ساده‌شده (بدون در نظر گ...
[ 5 ] - On the Security of O-PSI a Delegated Private Set Intersection on Outsourced Datasets (Extended Version)
In recent years, determining the common information privately and efficiently between two mutually mistrusting parties have become an important issue in social networks. Many Private set intersection (PSI) protocols have been introduced to address this issue. By applying these protocols, two parties can compute the intersection between their sets without disclosing any information about compone...
[ 6 ] - Impossible Differential Cryptanalysis of Reduced-Round Midori64 Block Cipher (Extended Version)
Impossible differential attack is a well-known mean to examine robustness of block ciphers. Using impossible differ- ential cryptanalysis, we analyze security of a family of lightweight block ciphers, named Midori, that are designed considering low energy consumption. Midori state size can be either 64 bits for Midori64 or 128 bits for Midori128; however, both vers...
[ 7 ] - Cryptanalysis of GSM encryption algorithm A5/1
The A5/1 algorithm is one of the most famous stream cipher algorithms used for over-the-air communication privacy in GSM. The purpose of this paper is to analyze several weaknesses of A5/1, including an improvement to an attack and investigation of the A5/1 state transition. Biham and Dunkelman proposed an attack on A5/1 with a time and data complexity of 239.91and 221.1, ...
[ 8 ] - On the multi _ chi-square tests and their data complexity
Chi-square tests are generally used for distinguishing purposes; however when they are combined to simultaneously test several independent variables, extra notation is required. In this study, the chi-square statistics in some previous works is revealed to be computed half of its real value. Therefore, the notion of Multi _ Chi-square tests is formulated to avoid possible future confusions. In ...
[ 9 ] - Double voter perceptible blind signature based electronic voting protocol
Mu et al. have proposed an electronic voting protocol and claimed that it protects anonymity of voters, detects double voting and authenticates eligible voters. It has been shown that it does not protect voter's privacy and prevent double voting. After that, several schemes have been presented to fulfill these properties. However, many of them suffer from the same weaknesses. In this p...
[ 10 ] - Biclique Cryptanalysis of Block Ciphers LBlock and TWINE-80 with Practical Data Complexity
In the biclique attack, a shorter biclique usually results in less data complexity, but at the expense of more computational complexity. The early abort technique can be used in partial matching part of the biclique attack in order to slightly reduce the computations. In this paper, we make use of this technique, but instead of slight improvement in the computational complexity, we keep the amo...
[ 11 ] - GSLHA: Group-based Secure Lightweight Handover Authentication Protocol for M2M Communication
Machine to machine (M2M) communication, which is also known as machine type communication (MTC), is one of the most fascinating parts of mobile communication technology and also an important practical application of the Internet of Things. The main objective of this type of communication, is handling massive heterogeneous devices with low network overheads and high security guarantees. Hence, v...
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