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Collision Attacks on Hash Functions Using Linearization of Compress Function
, M.Sc. Thesis Sharif University of Technology ; Aref, Mohammad Reza (Supervisor) ; Eghlidos, Taraneh (Supervisor)
Abstract
Collision attack is one of the usual attacks in cryptanalysis of hash functions. One method for applying this attack is linear approximation of equivalent compress function. Finding collisions for linearized compress function, having low Hamming weight, with a large probability could provide collisions for the main compress function. For this purpose, the problem of finding collision for used compress function is modeled by that of the linearized one, having low Hamming weight differences with a large probability. The problem of finding collisions with low Hamming weight differences is equivalent to the problem of finding codewords with low Hamming weights in linear binary code. Canteaut and...
Application of Karnaugh map for easy generation of error correcting codes
, Article Scientia Iranica ; Volume 19, Issue 3 , June , 2012 , Pages 690-695 ; 10263098 (ISSN) ; Sharif University of Technology
2012
Abstract
With increasing use of data transmission between digital systems as well as subsystems, the need for more reliable communication is felt. In this research, a new approach to the linear error correcting codes is introduced. Among advantages of this technique are simpler code construction and also decoding algorithm, as well as easier understanding of the basic concept. Based on an earlier paper and also recent work done, we first discuss briefly the use of Karnaugh map and its advantages in constructing simple codes. We then prove a theorem on application of the map to multiple error correcting codes. Using these results, we propose a simple technique that leads to obtaining a code with more...
Generalized multiple-access relay channel with confidential messages
, Article ISITA/ISSSTA 2010 - 2010 International Symposium on Information Theory and Its Applications, 17 October 2010 through 20 October 2010, Taichung ; 2010 , Pages 1024-1029 ; 9781424460175 (ISBN) ; Salimi, S ; Salmasizadeh, M ; Sharif University of Technology
2010
Abstract
In this paper, we propose information theoretic schemes that achieve the rate-equivocation regions for the multiple-access relay channel with confidential messages. This channel consists of two users that play the role of eavesdropper for each other's message and a relay that helps them to have a reliable and secure communication. The relay can itself be an eavesdropper of the users messages. The first coding scheme used for achievability is noise forwarding strategy and the second is the combination of noise forwarding with the compress and forward strategy. In the first one, relay cooperates with the users to have a confidential communication by sending codewords independent of the secret...
Joint sum rate and error probability optimization: finite blocklength analysis
, Article IEEE Wireless Communications Letters ; 2017 ; 21622337 (ISSN) ; Mili, M. R ; Makki, B ; Nasiri Kenari, M ; Svensson, T ; Sharif University of Technology
Abstract
We study the tradeoff between the sum rate and the error probability in downlink of wireless networks. Using the recent results on the achievable rates of finite-length codewords, the problem is cast as a joint optimization of the network sum rate and the per-user error probability. Moreover, we develop an efficient algorithm based on the divide-and-conquer technique to simultaneously maximize the network sum rate and minimize the maximum users’ error probability and to evaluate the effect of the codeword length on the system performance. The results show that, in delay-constrained scenarios, optimizing the per-user error probability plays a key role in achieving high throughput. IEEE
A new achievable rate-equivocation region for the relay-eavesdropper channel
, Article Proceedings - 2010 18th Iranian Conference on Electrical Engineering, ICEE 2010, 11 May 2010 through 13 May 2010 ; 2010 , Pages 188-193 ; 9781424467600 (ISBN) ; Salimi, S ; Salmasizadeh, M ; Sharif University of Technology
Abstract
In this paper, we propose an information-theoretic scheme which achieves a new rate-equivocation region for the four-terminal relay-eavesdropper channel. The coding scheme used to achieve this region is a combination of the partial decode and forward, compress and forward and noise forwarding strategies. In this strategy the relay cooperates with the source to have both a reliable and secure communication by decoding some part of the source message, compressing the received signal and also sending the codewords independent of the transmitted message. Using this scheme we can obtain the perfect secrecy capacity of the semi- deterministic and deterministic relay channels
Numeral-based crosstalk avoidance coding to reliable NoC design
, Article Proceedings - 2011 14th Euromicro Conference on Digital System Design: Architectures, Methods and Tools, DSD 2011 ; 2011 , Pages 55-62 ; 9780769544946 (ISBN) ; Patooghy, A ; Miremadi, S. G ; Sharif University of Technology
Abstract
This paper proposes a Numeral-Based Crosstalk Avoidance Coding (NB-CAC) to protect communication channels of Network-on-Chips (NoCs) against crosstalk faults. The NB-CAC scheme produces codewords without bit patterns '101' and '010' to eliminate harmful transition patterns from NoC channels. This is done by the use of a new numeral system proposed in the paper. Using the proposed numeral system, the NB-CAC scheme 1) can be utilized in NoC channels with any arbitrary width, and 2) can be implemented with low area, power, and timing overheads. VHDL and SPICE simulations have been carried out for a wide range of channel widths to evaluate delay, area, and power consumption of the NB-CAC codecs....