Cryptanalysis of CIKS-128 and CIKS-128H Suitable for Intelligent Multimedia and Ubiquitous Computing Systems

Recently, data-dependent permutations (DDP) that are very suitable for intelligent multimedia and ubiquitous computing systems have been introduced as a new cryptographic primitive for the design of fast encryption systems. The CIKS-128 and CIKS-128H block ciphers are the typical examples of DDP-based encryption algorithms. In this paper, we show that CIKS-128 and CIKS-128H are vulnerable to related-key differential attacks. We first describe how to construct their full-round related-key differential characteristics with high probabilities and then we exploit them to break the full-round CIKS-128 and CIKS-128H with 2^44, and 2^48 data/time complexities, respectively

Cryptoraptor : high throughput reconfigurable cryptographic processor for symmetric key encryption and cryptographic hash functions

textIn cryptographic processor design, the selection of functional primitives and connection structures between these primitives are extremely crucial to maximize throughput and flexibility. Hence, detailed analysis on the specifications and requirements of existing crypto-systems plays a crucial role in cryptographic processor design. This thesis provides the most comprehensive literature review that we are aware of on the widest range of existing cryptographic algorithms, their specifications, requirements, and hardware structures. In the light of this analysis, it also describes a high performance, low power, and highly flexible cryptographic processor, Cryptoraptor, that is designed to support both today's and tomorrow's encryption standards. To the best of our knowledge, the proposed cryptographic processor supports the widest range of cryptographic algorithms compared to other solutions in the literature and is the only crypto-specific processor targeting the future standards as well. Unlike previous work, we aim for maximum throughput for all known encryption standards, and to support future standards as well. Our 1GHz design achieves a peak throughput of 128Gbps for AES-128 which is competitive with ASIC designs and has 25X and 160X higher throughput per area than CPU and GPU solutions, respectively.Electrical and Computer Engineerin

Slide Attacks on a Class of Hash Functions

Abstract. This paper studies the application of slide attacks to hash functions. Slide attacks have mostly been used for block cipher cryptanalysis. But, as shown in the current paper, they also form a potential threat for hash functions, namely for sponge-function like structures. As it turns out, certain constructions for hash-function-based MACs can be vulnerable to forgery and even to key recovery attacks. In other cases, we can at least distinguish a given hash function from a random oracle. To illustrate our results, we describe attacks against the Grindahl-256 and Grindahl-512 hash functions. To the best of our knowledge, this is the first cryptanalytic result on Grindahl-512. Furthermore, we point out a slide-based distinguisher attack on a slightly modified version of RadioGatún. We finally discuss simple countermeasures as a defense against slide attacks. Key words: slide attacks, hash function, Grindahl, RadioGatún, MAC, sponge function.

Cryptanalysis of Block Ciphers

The block cipher is one of the most important primitives in modern cryptography, information and network security; one of the primary purposes of such ciphers is to provide confidentiality for data transmitted in insecure communication environments. To ensure that confidentiality is robustly provided, it is essential to investigate the security of a block cipher against a variety of cryptanalytic attacks. In this thesis, we propose a new extension of differential cryptanalysis, which we call the impossible boomerang attack. We describe the early abort technique for (related-key) impossible differential cryptanalysis and rectangle attacks. Finally, we analyse the security of a number of block ciphers that are currently being widely used or have recently been proposed for use in emerging cryptographic applications; our main cryptanalytic results are as follows. An impossible differential attack on 7-round AES when used with 128 or 192 key bits, and an impossible differential attack on 8-round AES when used with 256 key bits. An impossible boomerang attack on 6-round AES when used with 128 key bits, and an impossible boomerang attack on 7-round AES when used with 192 or 256 key bits. A related-key impossible boomerang attack on 8-round AES when used with 192 key bits, and a related-key impossible boomerang attack on 9-round AES when used with 256 key bits, both using two keys. An impossible differential attack on 11-round reduced Camellia when used with 128 key bits, an impossible differential attack on 12-round reduced Camellia when used with 192 key bits, and an impossible differential attack on 13-round reduced Camellia when used with 256 key bits. A related-key rectangle attack on the full Cobra-F64a, and a related-key differential attack on the full Cobra-F64b. A related-key rectangle attack on 44-round SHACAL-2. A related-key rectangle attack on 36-round XTEA. An impossible differential attack on 25-round reduced HIGHT, a related-key rectangle attack on 26-round reduced HIGHT, and a related-key impossible differential attack on 28-round reduced HIGHT. In terms of either the attack complexity or the numbers of attacked rounds, the attacks presented in the thesis are better than any previously published cryptanalytic results for the block ciphers concerned, except in the case of AES; for AES, the presented impossible differential attacks on 7-round AES used with 128 key bits and 8-round AES used with 256 key bits are the best currently published results on AES in a single key attack scenario, and the presented related-key impossible boomerang attacks on 8-round AES used with 192 key bits and 9-round AES used with 256 key bits are the best currently published results on AES in a related-key attack scenario involving two keys

Cryptanalysis and Design of Symmetric Primitives

Der Schwerpunkt dieser Dissertation liegt in der Analyse und dem Design von Block- chiffren und Hashfunktionen. Die Arbeit beginnt mit einer Einführung in Techniken zur Kryptoanalyse von Blockchiffren. Wir beschreiben diese Methoden und zeigen wie man daraus neue Techniken entwickeln kann, welche zu staerkeren Angriffen fuehren. Im zweiten Teil der Arbeit stellen wir eine Reihe von Angriffen auf eine Vielzahl von Blockchiffren dar. Wir haben dabei Angriffe auf reduzierte Versionen von ARIA und dem AES entwickelt. Darueber hinaus praesentieren wir im dritten Teil Angriffe auf interne Blockchiffren von Hashfunktionen. Wir entwickeln Angriffe, welche die inter- nen Blockchiffren von Tiger und HAS-160 auf volle Rundenanzahl brechen. Die hier vorgestellten Angriffe sind die ersten dieser Art. Ein Angriff auf eine reduzierte Ver- sion von SHACAL-2 welcher fast keinen Speicherbedarf hat, wird ebenfalls vorgestellt. Der vierte Teil der Arbeit befasst sich mit den Design und der Analyse von kryp- tographischen Hashfunktionen. Wir habe einen Slide Angriff, eine Technik welche aus der Analyse von Blockchiffren bekannt ist, im Kontext von Hashfunktionen zur Anwendung gebracht. Dabei praesentieren wir verschiedene Angriffe auf GRINDAHL und RADIOGATUN. Aufbauend auf den Angriffen des zweiten und dritten Teils dieser Arbeit stellen wir eine neue Hashfunktion vor, welche wir TWISTER nennen. TWISTER wurde fuer den SHA-3 Wettbewerb entwickelt und ist bereits zur ersten Runde angenommen.This thesis focuses on the cryptanalysis and the design of block ciphers and hash func- tions. The thesis starts with an overview of methods for cryptanalysis of block ciphers which are based on differential cryptanalysis. We explain these concepts and also sev- eral combinations of these attacks. We propose new attacks on reduced versions of ARIA and AES. Furthermore, we analyze the strength of the internal block ciphers of hash functions. We propose the first attacks that break the internal block ciphers of Tiger, HAS-160, and a reduced round version of SHACAL-2. The last part of the thesis is concerned with the analysis and the design of cryptographic hash functions. We adopt a block cipher attack called slide attack into the scenario of hash function cryptanalysis. We then use this new method to attack different variants of GRINDAHL and RADIOGATUN. Finally, we propose a new hash function called TWISTER which was designed and pro- posed for the SHA-3 competition. TWISTER was accepted for round one of this com- petition. Our approach follows a new strategy to design a cryptographic hash function. We also describe several attacks on TWISTER and discuss the security issues concern- ing these attack on TWISTER

A Salad of Block Ciphers

This book is a survey on the state of the art in block cipher design and analysis. It is work in progress, and it has been for the good part of the last three years -- sadly, for various reasons no significant change has been made during the last twelve months. However, it is also in a self-contained, useable, and relatively polished state, and for this reason I have decided to release this \textit{snapshot} onto the public as a service to the cryptographic community, both in order to obtain feedback, and also as a means to give something back to the community from which I have learned much. At some point I will produce a final version -- whatever being a ``final version\u27\u27 means in the constantly evolving field of block cipher design -- and I will publish it. In the meantime I hope the material contained here will be useful to other people