The Dblock Family of Block Ciphers
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The First Biclique Cryptanalysis of Serpent-256
The First Biclique Cryptanalysis of Serpent-256 Gabriel C. de Carvalho1, Luis A. B. Kowada1 1Instituto de Computac¸ao˜ – Universidade Federal Fluminense (UFF) – Niteroi´ – RJ – Brazil Abstract. The Serpent cipher was one of the finalists of the AES process and as of today there is no method for finding the key with fewer attempts than that of an exhaustive search of all possible keys, even when using known or chosen plaintexts for an attack. This work presents the first two biclique attacks for the full-round Serpent-256. The first uses a dimension 4 biclique while the second uses a dimension 8 biclique. The one with lower dimension covers nearly 4 complete rounds of the cipher, which is the reason for the lower time complex- ity when compared with the other attack (which covers nearly 3 rounds of the cipher). On the other hand, the second attack needs a lot less pairs of plain- texts for it to be done. The attacks require 2255:21 and 2255:45 full computations of Serpent-256 using 288 and 260 chosen ciphertexts respectively with negligible memory. 1. Introduction The Serpent cipher is, along with MARS, RC6, Twofish and Rijindael, one of the AES process finalists [Nechvatal et al. 2001] and has not had, since its proposal, its full round versions attacked. It is a Substitution Permutation Network (SPN) with 32 rounds, 128 bit block size and accepts keys of sizes 128, 192 and 256 bits. Serpent has been targeted by several cryptanalysis [Kelsey et al. 2000, Biham et al. 2001b, Biham et al. -
Differential Cryptanalysis of the BSPN Block Cipher Structure
Differential Cryptanalysis of the BSPN Block Cipher Structure Liam Keliher AceCrypt Research Group Department of Mathematics & Computer Science Mount Allison University Sackville, New Brunswick, Canada [email protected] Abstract. BSPN (byte-oriented SPN ) is a general block cipher struc ture presented at SAC’96 by Youssef et al. It was designed as a more ef ficient version of the bit-oriented SPN structure published earlier in 1996 by Heys and Tavares in the Journal of Cryptology. BSPN is a flexible SPN structure in which only the linear transformation layer is exactly specified, while s-boxes, key-scheduling details, and number of rounds are intentionally left unspecified. Because BSPN can be implemented very efficiently in hardware, several researchers have recommended the 64-bit version as a lightweight cipher for use in wireless sensor networks (WSNs). Youssef et al. perform preliminary analysis on BSPN (using typical block sizes and numbers of rounds) and claim it is resistant to differential and linear cryptanalysis. However, in this paper we show that even if BSPN (similarly parameterized) is instantiated with strong AES- like s-boxes, there exist high probability differentials that allow BSPN to be broken using differential cryptanalysis. In particular, up to 9 rounds of BSPN with a 64-bit block size can be attacked, and up to 18 rounds with a 128-bit block size can be attacked. Keywords: BSPN, block cipher, SPN, differential cryptanalysis, wire less sensor network (WSN) 1 Introduction BSPN (byte-oriented SPN ) is a general block cipher structure presented at SAC’96 by Youssef et al. [19]. It was designed as a more efficient byte-oriented version of the bit-oriented SPN structure published by Heys and Tavares in the Journal of Cryptology [5]. -
SHA-3 Conference, March 2012, Skein: More Than Just a Hash Function
Skein More than just a hash function Third SHA-3 Candidate Conference 23 March 2012 Washington DC 1 Skein is Skein-512 • Confusion is common, partially our fault • Skein has two special-purpose siblings: – Skein-256 for extreme memory constraints – Skein-1024 for the ultra-high security margin • But for SHA-3, Skein is Skein-512 – One hash function for all output sizes 2 Skein Architecture • Mix function is 64-bit ARX • Permutation: relocation of eight 64-bit words • Threefish: tweakable block cipher – Mix + Permutation – Simple key schedule – 72 rounds, subkey injection every four rounds – Tweakable-cipher design key to speed, security • Skein chains Threefish with UBI chaining mode – Tweakable mode based on MMO – Provable properties – Every hashed block is unique • Variable size output means flexible to use! – One function for any size output 3 The Skein/Threefish Mix 4 Four Threefish Rounds 5 Skein and UBI chaining 6 Fastest in Software • 5.5 cycles/byte on 64-bit reference platform • 17.4 cycles/byte on 32-bit reference platform • 4.7 cycles/byte on Itanium • 15.2 cycles/byte on ARM Cortex A8 (ARMv7) – New numbers, best finalist on ARMv7 (iOS, Samsung, etc.) 7 Fast and Compact in Hardware • Fast – Skein-512 at 32 Gbit/s in 32 nm in 58 k gates – (57 Gbit/s if processing two messages in parallel) • To maximize hardware performance: – Use a fast adder, rely on simple control structure, and exploit Threefish's opportunities for pipelining – Do not trust your EDA tool to generate an efficient implementation • Compact design: – Small FPGA -
Bicliques for Preimages: Attacks on Skein-512 and the SHA-2 Family
Bicliques for Preimages: Attacks on Skein-512 and the SHA-2 family Dmitry Khovratovich1 and Christian Rechberger2 and Alexandra Savelieva3 1Microsoft Research Redmond, USA 2DTU MAT, Denmark 3National Research University Higher School of Economics, Russia Abstract. We present the new concept of biclique as a tool for preimage attacks, which employs many powerful techniques from differential cryptanalysis of block ciphers and hash functions. The new tool has proved to be widely applicable by inspiring many authors to publish new re- sults of the full versions of AES, KASUMI, IDEA, and Square. In this paper, we demonstrate how our concept results in the first cryptanalysis of the Skein hash function, and describe an attack on the SHA-2 hash function with more rounds than before. Keywords: SHA-2, SHA-256, SHA-512, Skein, SHA-3, hash function, meet-in-the-middle attack, splice-and-cut, preimage attack, initial structure, biclique. 1 Introduction The last years saw an exciting progress in preimage attacks on hash functions. In contrast to collision search [29, 26], where differential cryptanalysis has been in use since 90s, there had been no similarly powerful tool for preimages. The situation changed dramatically in 2008, when the so-called splice-and-cut framework has been applied to MD4 and MD5 [2, 24], and later to SHA-0/1/2 [1, 3], Tiger [10], and other primitives. Despite amazing results on MD5, the applications to SHA-x primitives seemed to be limited by the internal properties of the message schedule procedures. The only promising element, the so-called initial structure tool, remained very informal and complicated. -
Darxplorer a Toolbox for Cryptanalysis and Cipher Designers
DARXplorer a Toolbox for Cryptanalysis and Cipher Designers Dennis Hoppe Bauhaus-University Weimar 22nd April 2009 Dennis Hoppe (BUW) DARXplorer 22nd April 2009 1 / 31 Agenda 1 Introduction to Hash Functions 2 The ThreeFish Block Cipher 3 Differential Cryptanalysis 4 DARXplorer { DC of ThreeFish 5 Results on ThreeFish 6 Generalization of DARXplorer Dennis Hoppe (BUW) DARXplorer 22nd April 2009 2 / 31 Agenda 1 Introduction to Hash Functions 2 The ThreeFish Block Cipher 3 Differential Cryptanalysis 4 DARXplorer { DC of ThreeFish 5 Results on ThreeFish 6 Generalization of DARXplorer Dennis Hoppe (BUW) DARXplorer 22nd April 2009 3 / 31 Introduction to Hash Functions Hash Functions A hash function H : f0; 1g∗ ! f0; 1gn is used to compute an n-bit fingerprint from an arbitrarily-sized input M 2 f0; 1g∗ Most of them are based on a compression function C : f0; 1gn × f0; 1gm ! f0; 1gn with fixed size input Computation: Hi := C(Hi−1;Mi) C C C H[0] H[1] . H[L-1] H[L] M[1] M[2] . M[L] Dennis Hoppe (BUW) DARXplorer 22nd April 2009 4 / 31 Introduction to Hash Functions { cont'd Compression Functions A crucial building block of iterated hash functions is the compression function C Designer often make use of block ciphers Which properties should be imposed on C to guarantee that the hash function satisfies certain properties? Theorem (Damg˚ard-Merkle) If the compression function C is collision-resistant, then the hash function H is collision-resistant as well. If the compression function C is preimage-resistant, then the hash function H is preimage-resistant as well. -
A Lightweight Encryption Algorithm for Secure Internet of Things
Pre-Print Version, Original article is available at (IJACSA) International Journal of Advanced Computer Science and Applications, Vol. 8, No. 1, 2017 SIT: A Lightweight Encryption Algorithm for Secure Internet of Things Muhammad Usman∗, Irfan Ahmedy, M. Imran Aslamy, Shujaat Khan∗ and Usman Ali Shahy ∗Faculty of Engineering Science and Technology (FEST), Iqra University, Defence View, Karachi-75500, Pakistan. Email: fmusman, [email protected] yDepartment of Electronic Engineering, NED University of Engineering and Technology, University Road, Karachi 75270, Pakistan. Email: firfans, [email protected], [email protected] Abstract—The Internet of Things (IoT) being a promising and apply analytics to share the most valuable data with the technology of the future is expected to connect billions of devices. applications. The IoT is taking the conventional internet, sensor The increased number of communication is expected to generate network and mobile network to another level as every thing mountains of data and the security of data can be a threat. The will be connected to the internet. A matter of concern that must devices in the architecture are essentially smaller in size and be kept under consideration is to ensure the issues related to low powered. Conventional encryption algorithms are generally confidentiality, data integrity and authenticity that will emerge computationally expensive due to their complexity and requires many rounds to encrypt, essentially wasting the constrained on account of security and privacy [4]. energy of the gadgets. Less complex algorithm, however, may compromise the desired integrity. In this paper we propose a A. Applications of IoT: lightweight encryption algorithm named as Secure IoT (SIT). -
Identifying Open Research Problems in Cryptography by Surveying Cryptographic Functions and Operations 1
International Journal of Grid and Distributed Computing Vol. 10, No. 11 (2017), pp.79-98 http://dx.doi.org/10.14257/ijgdc.2017.10.11.08 Identifying Open Research Problems in Cryptography by Surveying Cryptographic Functions and Operations 1 Rahul Saha1, G. Geetha2, Gulshan Kumar3 and Hye-Jim Kim4 1,3School of Computer Science and Engineering, Lovely Professional University, Punjab, India 2Division of Research and Development, Lovely Professional University, Punjab, India 4Business Administration Research Institute, Sungshin W. University, 2 Bomun-ro 34da gil, Seongbuk-gu, Seoul, Republic of Korea Abstract Cryptography has always been a core component of security domain. Different security services such as confidentiality, integrity, availability, authentication, non-repudiation and access control, are provided by a number of cryptographic algorithms including block ciphers, stream ciphers and hash functions. Though the algorithms are public and cryptographic strength depends on the usage of the keys, the ciphertext analysis using different functions and operations used in the algorithms can lead to the path of revealing a key completely or partially. It is hard to find any survey till date which identifies different operations and functions used in cryptography. In this paper, we have categorized our survey of cryptographic functions and operations in the algorithms in three categories: block ciphers, stream ciphers and cryptanalysis attacks which are executable in different parts of the algorithms. This survey will help the budding researchers in the society of crypto for identifying different operations and functions in cryptographic algorithms. Keywords: cryptography; block; stream; cipher; plaintext; ciphertext; functions; research problems 1. Introduction Cryptography [1] in the previous time was analogous to encryption where the main task was to convert the readable message to an unreadable format. -
Deep Learning-Based Cryptanalysis of Lightweight Block Ciphers
Hindawi Security and Communication Networks Volume 2020, Article ID 3701067, 11 pages https://doi.org/10.1155/2020/3701067 Research Article Deep Learning-Based Cryptanalysis of Lightweight Block Ciphers Jaewoo So Department of Electronic Engineering, Sogang University, Seoul 04107, Republic of Korea Correspondence should be addressed to Jaewoo So; [email protected] Received 5 February 2020; Revised 21 June 2020; Accepted 26 June 2020; Published 13 July 2020 Academic Editor: Umar M. Khokhar Copyright © 2020 Jaewoo So. +is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Most of the traditional cryptanalytic technologies often require a great amount of time, known plaintexts, and memory. +is paper proposes a generic cryptanalysis model based on deep learning (DL), where the model tries to find the key of block ciphers from known plaintext-ciphertext pairs. We show the feasibility of the DL-based cryptanalysis by attacking on lightweight block ciphers such as simplified DES, Simon, and Speck. +e results show that the DL-based cryptanalysis can successfully recover the key bits when the keyspace is restricted to 64 ASCII characters. +e traditional cryptanalysis is generally performed without the keyspace restriction, but only reduced-round variants of Simon and Speck are successfully attacked. Although a text-based key is applied, the proposed DL-based cryptanalysis can successfully break the full rounds of Simon32/64 and Speck32/64. +e results indicate that the DL technology can be a useful tool for the cryptanalysis of block ciphers when the keyspace is restricted. -
Cryptanalysis of Block Ciphers, Stream Ciphers, Modes of Operation Of
Outline Computer Science 418 1 Attacks on Block Ciphers Security of Block Ciphers, Stream Ciphers, Modes of Operation Exhaustive Attacks Meet-in-the-Middle Attack on Double Encryption Analytic Attacks Mike Jacobson 2 Stream Ciphers Department of Computer Science University of Calgary Synchronous Stream Ciphers (SSC) Self-Synchronizing Stream Ciphers (Self-SSC) Week 6 3 Modes of Operation for Block Ciphers Mike Jacobson (University of Calgary) Computer Science 418 Week 6 1 / 34 Mike Jacobson (University of Calgary) Computer Science 418 Week 6 2 / 34 Attacks on Block Ciphers Attacks on Block Ciphers Exhaustive Attacks Security of AES Exhaustive Search Set N = jKj (number of keys). Simple exhaustive search (COA) | requires jKj encryptions There is no mathematical proof that AES is secure feasible for DES | N = 256 ≈ 1017 possible keys. 112 34 All we know is that in practice, it withstands all modern attacks. infeasible for 3DES { N = 2 ≈ 10 possible key combinations. infeasible for AES { N = 2128 ≈ 1038 possible keys This lecture: overview of modern attacks on block ciphers Parallelism can speed up exhaustive search. Perspective: there are approximately 1040 water molecules in Lake Ontario. 1038 is significantly bigger than the number of water molecules in Lake Louise or in the stretch of the Bow River through Calgary! Mike Jacobson (University of Calgary) Computer Science 418 Week 6 3 / 34 Mike Jacobson (University of Calgary) Computer Science 418 Week 6 4 / 34 Attacks on Block Ciphers Exhaustive Attacks Attacks on Block Ciphers Exhaustive Attacks Improvement for DES Hellman's Time-memory tradeoff (1980) KPA that shortens search time by using a lot of memory. -
Future Internet (FI) and Innovative Internet Technologies and Mobile Communication (IITM)
Chair of Network Architectures and Services Department of Informatics Technical University of Munich Proceedings of the Seminars Future Internet (FI) and Innovative Internet Technologies and Mobile Communication (IITM) Summer Semester 2018 26. 2. 2017 – 19. 8. 2018 Munich, Germany Editors Georg Carle, Daniel Raumer, Stephan Gunther,¨ Benedikt Jaeger Publisher Chair of Network Architectures and Services Network Architectures and Services NET 2018-11-1 Lehrstuhl für Netzarchitekturen und Netzdienste Fakultät für Informatik Technische Universität München Proceedings zu den Seminaren Future Internet (FI) und Innovative Internet-Technologien und Mobilkommunikation (IITM) Sommersemester 2018 München, 26. 2. 2017 – 19. 8. 2018 Editoren: Georg Carle, Daniel Raumer, Stephan Günther, Benedikt Jaeger Network Architectures and Services NET 2018-11-1 Proceedings of the Seminars Future Internet (FI) and Innovative Internet Technologies and Mobile Communication (IITM) Summer Semester 2018 Editors: Georg Carle Lehrstuhl für Netzarchitekturen und Netzdienste (I8) Technische Universität München 85748 Garching b. München, Germany E-mail: [email protected] Internet: https://net.in.tum.de/~carle/ Daniel Raumer Lehrstuhl für Netzarchitekturen und Netzdienste (I8) E-mail: [email protected] Internet: https://net.in.tum.de/~raumer/ Stephan Günther Lehrstuhl für Netzarchitekturen und Netzdienste (I8) E-mail: [email protected] Internet: https://net.in.tum.de/~guenther/ Benedikt Jaeger Lehrstuhl für Netzarchitekturen und Netzdienste (I8) E-mail: [email protected] Internet: https://net.in.tum.de/~jaeger/ Cataloging-in-Publication Data Seminars FI & IITM SS 18 Proceedings zu den Seminaren „Future Internet“ (FI) und „Innovative Internet-Technologien und Mobilkom- munikation“ (IITM) München, Germany, 26. 2. 2017 – 19. 8. -
ICEBERG : an Involutional Cipher Efficient for Block Encryption in Reconfigurable Hardware
1 ICEBERG : an Involutional Cipher Efficient for Block Encryption in Reconfigurable Hardware. Francois-Xavier Standaert, Gilles Piret, Gael Rouvroy, Jean-Jacques Quisquater, Jean-Didier Legat UCL Crypto Group Laboratoire de Microelectronique Universite Catholique de Louvain Place du Levant, 3, B-1348 Louvain-La-Neuve, Belgium standaert,piret,rouvroy,quisquater,[email protected] Abstract. We present a fast involutional block cipher optimized for re- configurable hardware implementations. ICEBERG uses 64-bit text blocks and 128-bit keys. All components are involutional and allow very effi- cient combinations of encryption/decryption. Hardware implementations of ICEBERG allow to change the key at every clock cycle without any per- formance loss and its round keys are derived “on-the-fly” in encryption and decryption modes (no storage of round keys is needed). The result- ing design offers better hardware efficiency than other recent 128-key-bit block ciphers. Resistance against side-channel cryptanalysis was also con- sidered as a design criteria for ICEBERG. Keywords: block cipher design, efficient implementations, reconfigurable hardware, side-channel resistance. 1 Introduction In October 2000, NIST (National Institute of Standards and Technology) se- lected Rijndael as the new Advanced Encryption Standard. The selection pro- cess included performance evaluation on both software and hardware platforms. However, as implementation versatility was a criteria for the selection of the AES, it appeared that Rijndael is not optimal for reconfigurable hardware im- plementations. Its highly expensive substitution boxes are a typical bottleneck but the combination of encryption and decryption in hardware is probably as critical. In general, observing the AES candidates [1, 2], one may assess that the cri- teria selected for their evaluation led to highly conservative designs although the context of certain cryptanalysis may be considered as very unlikely (e.g. -
A Re-Examine on Assorted Digital Image Encryption Algorithm's
Biostatistics and Biometrics Open Access Journal ISSN: 2573-2633 Review Article Biostat Biometrics Open Acc J Volume 4 Issue 2 - January 2018 Copyright © All rights are reserved by Thippanna G DOI: 10.19080/BBOAJ.2018.04.555633 A Re-Examine on Assorted Digital Image Encryption Algorithm’s Techniques Thippanna G* Assistant Professor, CSSR & SRRM Degree and PG College, India Submission: October 05, 2017; Published: January 17, 2018 *Corresponding author: Thippanna G, Assistant Professor, CSSR & SRRM Degree and PG College, India, Tel: ; Email: Abstract Image Encryption is a wide area epic topic to research. Encryption basically deals with converting data or information from its original form to another unreadable and unrecognizable form that hides the information in it. The protection of information from unauthorized access is important in network/internet communication. The use of Encryption is provides the data security. The Encrypted Image is secure from any kind cryptanalysis. In the proposed dissertation explain the different encryption algorithms and their approaches to encrypt the images. In this paper introduced a case study on assorted digital image encryption techniques, are helpful to gives knowledge on entire digital image encryption techniques. This can offer authentication of users, and integrity, accuracy and safety of images that is roaming over communication. Moreover, associate image based knowledge needs additional effort throughout encoding and cryptography. Keywords : Encryption; Cryptanalysis; Cryptographic; Algorithm; Block ciphers; Stream ciphers; Asymmetric Encryption Abbreviations : AES: Advanced Encryption Standard; DSA: Digital Signature Algorithm; DSS: Digital Signature Standard; ECDSA: Elliptic Curve Digital Signature Algorithm; DSA: Digital Signature Algorithm Introduction Some cryptographic methods rely on the secrecy of the Encryption algorithms encryption algorithms; such algorithms are only of historical Encryption algorithm, or cipher, is a mathematical function interest and are not adequate for real-world needs.