Combined attacks on block ciphers

Download

index.pdf

Date

2009

Author

Öztop, Neşe

Metadata

Show full item record

Item Usage Stats

288
views

223
downloads

Cryptanalytic methods are very important tools in terms of evaluating the security of block ciphers in a more accurate and reliable way. Differential and linear attacks have been the most effective cryptanalysis methods since the early 1990s. However, as the technology developed and more secure ciphers are designed, these fundamental methods started to be not so efficient. In order to analyze the ciphers, new methods should be introduced. One approach is inventing new techniques that are different from the existing ones. Another approach is extending or combining known cryptanalytic methods to analyze the cipher in a different way. This thesis is a survey of the attacks that are generated by combination of existing techniques and their applications on specific block ciphers. Mentioned attacks are namely differential-linear, differential-bilinear, higher order differential-linear, differential-nonlinear, square-nonlinear, impossible differential and boomerang type attacks.

Subject Keywords

Cryptography.

URI

http://etd.lib.metu.edu.tr/upload/2/12610875/index.pdf
https://hdl.handle.net/11511/18605

Collections

Graduate School of Applied Mathematics, Thesis

Suggestions

OpenMETU
Core

Basic cryptanalysis methods on block ciphers Çelik, Dilek; Doğanaksoy, Ali; Department of Cryptography (2010) Differential cryptanalysis and linear cryptanalysis are the first significant methods used to attack on block ciphers. These concepts compose the keystones for most of the attacks in recent years. Also, while designing a cipher, these attacks should be taken into consideration and the cipher should be created as secure against them. Although di fferential cryptanalysis and linear cryptanalysis are still important, they started to be ine cient due to the improvements in the technology. So, these attacks are ...
Statistical analysis of block ciphers and hash functions Sulak, Fatih; Doğanaksoy, Ali; Department of Cryptography (2011) One of the most basic properties expected from block ciphers and hash functions is passing statistical randomness testing, as they are supposed to behave like random mappings. Previously, testing of AES candidate block ciphers was done by using the statistical tests defined in the NIST Test Suite. As some of the tests in this suite require long sequences, data sets are formed by concatenating the outputs of the algorithms obtained from various input types. However, the nature of block cipher and hash functi...
Design and analysis of hash functions Koçak, Onur; Doğanaksoy, Ali; Department of Cryptography (2009) Hash functions are cryptographic tools that are used in various applications like digital signature, message integrity checking, password storage and random number generation. These cryptographic primitives were, first, constructed using modular arithmetical operations which were popular at that time because of public key cryptography. Later, in 1989, Merkle and Damgard independently proposed an iterative construction method. This method was easy to implement and had a security proof. MD-4 was the first has...
Impossible differential cryptanalysis of reduced round HIGHT Tezcan, Cihangir; Doğanaksoy, Ali; Department of Cryptography (2009) Design and analysis of lightweight block ciphers have become more popular due to the fact that the future use of block ciphers in ubiquitous devices is generally assumed to be extensive. In this respect, several lightweight block ciphers are designed, of which HIGHT is proposed by Hong et al. at CHES 2006 as a constrained hardware oriented block cipher. HIGHT is shown to be highly convenient for extremely constrained devices such as RFID tags and sensor networks and it became a standard encryption algorithm...
On statistical analysis of synchronous stream ciphers Sönmez Turan, Meltem; Doğanaksoy, Ali; Department of Cryptography (2008) Synchronous stream ciphers constitute an important class of symmetric ciphers. After the call of the eSTREAM project in 2004, 34 stream ciphers with different design approaches were proposed. In this thesis, we aim to provide a general framework to analyze stream ciphers statistically. Firstly, we consider stream ciphers as pseudo random number generators and study the quality of their output. We propose three randomness tests based on one dimensional random walks. Moreover, we theoretically and experimenta...

Citation Formats

N. Öztop, “Combined attacks on block ciphers,” M.S. - Master of Science, Middle East Technical University, 2009.