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The Design of Rijndael: AES - the Advanced Encryption Standard/Joan Daemen, Vincent Rijmen
Joan Daernen · Vincent Rijrnen Theof Design Rijndael AES - The Advanced Encryption Standard With 48 Figures and 17 Tables Springer Berlin Heidelberg New York Barcelona Hong Kong London Milan Paris Springer TnL-1Jn Joan Daemen Foreword Proton World International (PWI) Zweefvliegtuigstraat 10 1130 Brussels, Belgium Vincent Rijmen Cryptomathic NV Lei Sa 3000 Leuven, Belgium Rijndael was the surprise winner of the contest for the new Advanced En cryption Standard (AES) for the United States. This contest was organized and run by the National Institute for Standards and Technology (NIST) be ginning in January 1997; Rij ndael was announced as the winner in October 2000. It was the "surprise winner" because many observers (and even some participants) expressed scepticism that the U.S. government would adopt as Library of Congress Cataloging-in-Publication Data an encryption standard any algorithm that was not designed by U.S. citizens. Daemen, Joan, 1965- Yet NIST ran an open, international, selection process that should serve The design of Rijndael: AES - The Advanced Encryption Standard/Joan Daemen, Vincent Rijmen. as model for other standards organizations. For example, NIST held their p.cm. Includes bibliographical references and index. 1999 AES meeting in Rome, Italy. The five finalist algorithms were designed ISBN 3540425802 (alk. paper) . .. by teams from all over the world. 1. Computer security - Passwords. 2. Data encryption (Computer sCIence) I. RIJmen, In the end, the elegance, efficiency, security, and principled design of Vincent, 1970- II. Title Rijndael won the day for its two Belgian designers, Joan Daemen and Vincent QA76.9.A25 D32 2001 Rijmen, over the competing finalist designs from RSA, IBl\!I, Counterpane 2001049851 005.8-dc21 Systems, and an English/Israeli/Danish team. -
Improved Rectangle Attacks on SKINNY and CRAFT
Improved Rectangle Attacks on SKINNY and CRAFT Hosein Hadipour1, Nasour Bagheri2 and Ling Song3( ) 1 Department of Mathematics and Computer Science, University of Tehran, Tehran, Iran, [email protected] 2 Electrical Engineering Department, Shahid Rajaee Teacher Training University, Tehran, Iran, [email protected] 3 Jinan University, Guangzhou, China [email protected] Abstract. The boomerang and rectangle attacks are adaptions of differential crypt- analysis that regard the target cipher E as a composition of two sub-ciphers, i.e., 2 2 E = E1 ◦ E0, to construct a distinguisher for E with probability p q by concatenat- ing two short differential trails for E0 and E1 with probability p and q respectively. According to the previous research, the dependency between these two differential characteristics has a great impact on the probability of boomerang and rectangle distinguishers. Dunkelman et al. proposed the sandwich attack to formalise such dependency that regards E as three parts, i.e., E = E1 ◦ Em ◦ E0, where Em contains the dependency between two differential trails, satisfying some differential propagation with probability r. Accordingly, the entire probability is p2q2r. Recently, Song et al. have proposed a general framework to identify the actual boundaries of Em and systematically evaluate the probability of Em with any number of rounds, and applied their method to accurately evaluate the probabilities of the best SKINNY’s boomerang distinguishers. In this paper, using a more advanced method to search for boomerang distinguishers, we show that the best previous boomerang distinguishers for SKINNY can be significantly improved in terms of probability and number of rounds. -
Basic Cryptography
Basic cryptography • How cryptography works... • Symmetric cryptography... • Public key cryptography... • Online Resources... • Printed Resources... I VP R 1 © Copyright 2002-2007 Haim Levkowitz How cryptography works • Plaintext • Ciphertext • Cryptographic algorithm • Key Decryption Key Algorithm Plaintext Ciphertext Encryption I VP R 2 © Copyright 2002-2007 Haim Levkowitz Simple cryptosystem ... ! ABCDEFGHIJKLMNOPQRSTUVWXYZ ! DEFGHIJKLMNOPQRSTUVWXYZABC • Caesar Cipher • Simple substitution cipher • ROT-13 • rotate by half the alphabet • A => N B => O I VP R 3 © Copyright 2002-2007 Haim Levkowitz Keys cryptosystems … • keys and keyspace ... • secret-key and public-key ... • key management ... • strength of key systems ... I VP R 4 © Copyright 2002-2007 Haim Levkowitz Keys and keyspace … • ROT: key is N • Brute force: 25 values of N • IDEA (international data encryption algorithm) in PGP: 2128 numeric keys • 1 billion keys / sec ==> >10,781,000,000,000,000,000,000 years I VP R 5 © Copyright 2002-2007 Haim Levkowitz Symmetric cryptography • DES • Triple DES, DESX, GDES, RDES • RC2, RC4, RC5 • IDEA Key • Blowfish Plaintext Encryption Ciphertext Decryption Plaintext Sender Recipient I VP R 6 © Copyright 2002-2007 Haim Levkowitz DES • Data Encryption Standard • US NIST (‘70s) • 56-bit key • Good then • Not enough now (cracked June 1997) • Discrete blocks of 64 bits • Often w/ CBC (cipherblock chaining) • Each blocks encr. depends on contents of previous => detect missing block I VP R 7 © Copyright 2002-2007 Haim Levkowitz Triple DES, DESX, -
Lecture Note 8 ATTACKS on CRYPTOSYSTEMS I Sourav Mukhopadhyay
Lecture Note 8 ATTACKS ON CRYPTOSYSTEMS I Sourav Mukhopadhyay Cryptography and Network Security - MA61027 Attacks on Cryptosystems • Up to this point, we have mainly seen how ciphers are implemented. • We have seen how symmetric ciphers such as DES and AES use the idea of substitution and permutation to provide security and also how asymmetric systems such as RSA and Diffie Hellman use other methods. • What we haven’t really looked at are attacks on cryptographic systems. Cryptography and Network Security - MA61027 (Sourav Mukhopadhyay, IIT-KGP, 2010) 1 • An understanding of certain attacks will help you to understand the reasons behind the structure of certain algorithms (such as Rijndael) as they are designed to thwart known attacks. • Although we are not going to exhaust all possible avenues of attack, we will get an idea of how cryptanalysts go about attacking ciphers. Cryptography and Network Security - MA61027 (Sourav Mukhopadhyay, IIT-KGP, 2010) 2 • This section is really split up into two classes of attack: Cryptanalytic attacks and Implementation attacks. • The former tries to attack mathematical weaknesses in the algorithms whereas the latter tries to attack the specific implementation of the cipher (such as a smartcard system). • The following attacks can refer to either of the two classes (all forms of attack assume the attacker knows the encryption algorithm): Cryptography and Network Security - MA61027 (Sourav Mukhopadhyay, IIT-KGP, 2010) 3 – Ciphertext-only attack: In this attack the attacker knows only the ciphertext to be decoded. The attacker will try to find the key or decrypt one or more pieces of ciphertext (only relatively weak algorithms fail to withstand a ciphertext-only attack). -
Analysis of Selected Block Cipher Modes for Authenticated Encryption
Analysis of Selected Block Cipher Modes for Authenticated Encryption by Hassan Musallam Ahmed Qahur Al Mahri Bachelor of Engineering (Computer Systems and Networks) (Sultan Qaboos University) – 2007 Thesis submitted in fulfilment of the requirement for the degree of Doctor of Philosophy School of Electrical Engineering and Computer Science Science and Engineering Faculty Queensland University of Technology 2018 Keywords Authenticated encryption, AE, AEAD, ++AE, AEZ, block cipher, CAESAR, confidentiality, COPA, differential fault analysis, differential power analysis, ElmD, fault attack, forgery attack, integrity assurance, leakage resilience, modes of op- eration, OCB, OTR, SHELL, side channel attack, statistical fault analysis, sym- metric encryption, tweakable block cipher, XE, XEX. i ii Abstract Cryptography assures information security through different functionalities, es- pecially confidentiality and integrity assurance. According to Menezes et al. [1], confidentiality means the process of assuring that no one could interpret infor- mation, except authorised parties, while data integrity is an assurance that any unauthorised alterations to a message content will be detected. One possible ap- proach to ensure confidentiality and data integrity is to use two different schemes where one scheme provides confidentiality and the other provides integrity as- surance. A more compact approach is to use schemes, called Authenticated En- cryption (AE) schemes, that simultaneously provide confidentiality and integrity assurance for a message. AE can be constructed using different mechanisms, and the most common construction is to use block cipher modes, which is our focus in this thesis. AE schemes have been used in a wide range of applications, and defined by standardisation organizations. The National Institute of Standards and Technol- ogy (NIST) recommended two AE block cipher modes CCM [2] and GCM [3]. -
On the Decorrelated Fast Cipher (DFC) and Its Theory
On the Decorrelated Fast Cipher (DFC) and Its Theory Lars R. Knudsen and Vincent Rijmen ? Department of Informatics, University of Bergen, N-5020 Bergen Abstract. In the first part of this paper the decorrelation theory of Vaudenay is analysed. It is shown that the theory behind the propo- sed constructions does not guarantee security against state-of-the-art differential attacks. In the second part of this paper the proposed De- correlated Fast Cipher (DFC), a candidate for the Advanced Encryption Standard, is analysed. It is argued that the cipher does not obtain prova- ble security against a differential attack. Also, an attack on DFC reduced to 6 rounds is given. 1 Introduction In [6,7] a new theory for the construction of secret-key block ciphers is given. The notion of decorrelation to the order d is defined. Let C be a block cipher with block size m and C∗ be a randomly chosen permutation in the same message space. If C has a d-wise decorrelation equal to that of C∗, then an attacker who knows at most d − 1 pairs of plaintexts and ciphertexts cannot distinguish between C and C∗. So, the cipher C is “secure if we use it only d−1 times” [7]. It is further noted that a d-wise decorrelated cipher for d = 2 is secure against both a basic linear and a basic differential attack. For the latter, this basic attack is as follows. A priori, two values a and b are fixed. Pick two plaintexts of difference a and get the corresponding ciphertexts. -
Serpent: a Proposal for the Advanced Encryption Standard
Serpent: A Proposal for the Advanced Encryption Standard Ross Anderson1 Eli Biham2 Lars Knudsen3 1 Cambridge University, England; email [email protected] 2 Technion, Haifa, Israel; email [email protected] 3 University of Bergen, Norway; email [email protected] Abstract. We propose a new block cipher as a candidate for the Ad- vanced Encryption Standard. Its design is highly conservative, yet still allows a very efficient implementation. It uses S-boxes similar to those of DES in a new structure that simultaneously allows a more rapid avalanche, a more efficient bitslice implementation, and an easy anal- ysis that enables us to demonstrate its security against all known types of attack. With a 128-bit block size and a 256-bit key, it is as fast as DES on the market leading Intel Pentium/MMX platforms (and at least as fast on many others); yet we believe it to be more secure than three-key triple-DES. 1 Introduction For many applications, the Data Encryption Standard algorithm is nearing the end of its useful life. Its 56-bit key is too small, as shown by a recent distributed key search exercise [28]. Although triple-DES can solve the key length problem, the DES algorithm was also designed primarily for hardware encryption, yet the great majority of applications that use it today implement it in software, where it is relatively inefficient. For these reasons, the US National Institute of Standards and Technology has issued a call for a successor algorithm, to be called the Advanced Encryption Standard or AES. -
Report on the AES Candidates
Rep ort on the AES Candidates 1 2 1 3 Olivier Baudron , Henri Gilb ert , Louis Granb oulan , Helena Handschuh , 4 1 5 1 Antoine Joux , Phong Nguyen ,Fabrice Noilhan ,David Pointcheval , 1 1 1 1 Thomas Pornin , Guillaume Poupard , Jacques Stern , and Serge Vaudenay 1 Ecole Normale Sup erieure { CNRS 2 France Telecom 3 Gemplus { ENST 4 SCSSI 5 Universit e d'Orsay { LRI Contact e-mail: [email protected] Abstract This do cument rep orts the activities of the AES working group organized at the Ecole Normale Sup erieure. Several candidates are evaluated. In particular we outline some weaknesses in the designs of some candidates. We mainly discuss selection criteria b etween the can- didates, and make case-by-case comments. We nally recommend the selection of Mars, RC6, Serp ent, ... and DFC. As the rep ort is b eing nalized, we also added some new preliminary cryptanalysis on RC6 and Crypton in the App endix which are not considered in the main b o dy of the rep ort. Designing the encryption standard of the rst twentyyears of the twenty rst century is a challenging task: we need to predict p ossible future technologies, and wehavetotake unknown future attacks in account. Following the AES pro cess initiated by NIST, we organized an op en working group at the Ecole Normale Sup erieure. This group met two hours a week to review the AES candidates. The present do cument rep orts its results. Another task of this group was to up date the DFC candidate submitted by CNRS [16, 17] and to answer questions which had b een omitted in previous 1 rep orts on DFC. -
The EAX Mode of Operation
A preliminary version of this papers appears in Fast Software Encryption ’04, Lecture Notes in Computer Science, vol. ?? , R. Bimal and W. Meier ed., Springer-Verlag, 2004. This is the full version. The EAX Mode of Operation (A Two-Pass Authenticated-Encryption Scheme Optimized for Simplicity and Efficiency) ∗ † ‡ M. BELLARE P. ROGAWAY D. WAGNER January 18, 2004 Abstract We propose a block-cipher mode of operation, EAX, for solving the problem of authenticated-encryption with associated-data (AEAD). Given a nonce N, a message M, and a header H, our mode protects the privacy of M and the authenticity of both M and H. Strings N, M, and H are arbitrary bit strings, and the mode uses 2|M|/n + |H|/n + |N|/n block-cipher calls when these strings are nonempty and n is the block length of the underlying block cipher. Among EAX’s characteristics are that it is on-line (the length of a message isn’t needed to begin processing it) and a fixed header can be pre-processed, effectively removing the per-message cost of binding it to the ciphertext. EAX is obtained by first creating a generic-composition method, EAX2, and then collapsing its two keys into one. EAX is provably secure under a standard complexity-theoretic assumption. The proof of this fact is novel and involved. EAX is an alternative to CCM [26], which was created to answer the wish within standards bodies for a fully-specified and patent-free AEAD mode. As such, CCM and EAX are two-pass schemes, with one pass for achieving privacy and one for authenticity. -
The Mathemathics of Secrets.Pdf
THE MATHEMATICS OF SECRETS THE MATHEMATICS OF SECRETS CRYPTOGRAPHY FROM CAESAR CIPHERS TO DIGITAL ENCRYPTION JOSHUA HOLDEN PRINCETON UNIVERSITY PRESS PRINCETON AND OXFORD Copyright c 2017 by Princeton University Press Published by Princeton University Press, 41 William Street, Princeton, New Jersey 08540 In the United Kingdom: Princeton University Press, 6 Oxford Street, Woodstock, Oxfordshire OX20 1TR press.princeton.edu Jacket image courtesy of Shutterstock; design by Lorraine Betz Doneker All Rights Reserved Library of Congress Cataloging-in-Publication Data Names: Holden, Joshua, 1970– author. Title: The mathematics of secrets : cryptography from Caesar ciphers to digital encryption / Joshua Holden. Description: Princeton : Princeton University Press, [2017] | Includes bibliographical references and index. Identifiers: LCCN 2016014840 | ISBN 9780691141756 (hardcover : alk. paper) Subjects: LCSH: Cryptography—Mathematics. | Ciphers. | Computer security. Classification: LCC Z103 .H664 2017 | DDC 005.8/2—dc23 LC record available at https://lccn.loc.gov/2016014840 British Library Cataloging-in-Publication Data is available This book has been composed in Linux Libertine Printed on acid-free paper. ∞ Printed in the United States of America 13579108642 To Lana and Richard for their love and support CONTENTS Preface xi Acknowledgments xiii Introduction to Ciphers and Substitution 1 1.1 Alice and Bob and Carl and Julius: Terminology and Caesar Cipher 1 1.2 The Key to the Matter: Generalizing the Caesar Cipher 4 1.3 Multiplicative Ciphers 6 -
Mcoe: a Family of Almost Foolproof On-Line Authenticated Encryption Schemes
McOE: A Family of Almost Foolproof On-Line Authenticated Encryption Schemes Ewan Fleischmann Christian Forler Stefan Lucks Bauhaus-Universit¨atWeimar FSE 2012 Fleischmann, Forler, Lucks. FSE 2012. McOE: A Family . {1{ Overview Fleischmann, Forler, Lucks. FSE 2012. McOE: A Family . {2{ 1. Motivation I Goldwasser and Micali (1984): requirement: given 2 ciphertexts, adversary cannot even detect when the same plaintext has been encrypted twice consequence: encryption stateful or probabilitistic (or both) I Rogaway (FSE 2004): formalizes state/randomness by nonces Plaintext Header Key Nonce 01 02 03 ... Ciphertext Authentication Tag Fleischmann, Forler, Lucks. FSE 2012. McOE: A Family . {3{ Authenticated Encryption I first studied by Katz and Young (FSE 2000) and Bellare and Namprempre (Asiacrypt 2000) I since then many proposed schemes, I nonce based, Plaintext Header Key Nonce I and proven secure assuming a \nonce-respecting01 02 03 ... adversary" I any implementation allowing a nonce reuse is not our problem . but maybe it shouldCiphertext Authentication Tag Fleischmann, Forler, Lucks. FSE 2012. McOE: A Family . {4{ Nonce Reuse in Practice I IEEE 802.11 [Borisov, Goldberg, Wagner 2001] I PS3 [Hotz 2010] I WinZip Encryption [Kohno 2004] I RC4 in MS Word and Excel [Wu 2005] I ... application programmer other issues: mistakes: I restoring a file from a backup I cloning the virtual machine the application runs on I ... Fleischmann, Forler, Lucks. FSE 2012. McOE: A Family . {5{ Nonce Reuse { what to Expect? our reasonable (?) expectations I some plaintext information leaks: I identical plaintexts I common prefixes I ect. I but not too much damage: 1. authentication not affected 2. -
Optimization of Core Components of Block Ciphers Baptiste Lambin
Optimization of core components of block ciphers Baptiste Lambin To cite this version: Baptiste Lambin. Optimization of core components of block ciphers. Cryptography and Security [cs.CR]. Université Rennes 1, 2019. English. NNT : 2019REN1S036. tel-02380098 HAL Id: tel-02380098 https://tel.archives-ouvertes.fr/tel-02380098 Submitted on 26 Nov 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. THÈSE DE DOCTORAT DE L’UNIVERSITE DE RENNES 1 COMUE UNIVERSITE BRETAGNE LOIRE Ecole Doctorale N°601 Mathématique et Sciences et Technologies de l’Information et de la Communication Spécialité : Informatique Par Baptiste LAMBIN Optimization of Core Components of Block Ciphers Thèse présentée et soutenue à RENNES, le 22/10/2019 Unité de recherche : IRISA Rapporteurs avant soutenance : Marine Minier, Professeur, LORIA, Université de Lorraine Jacques Patarin, Professeur, PRiSM, Université de Versailles Composition du jury : Examinateurs : Marine Minier, Professeur, LORIA, Université de Lorraine Jacques Patarin, Professeur, PRiSM, Université de Versailles Jean-Louis Lanet, INRIA Rennes Virginie Lallemand, Chargée de Recherche, LORIA, CNRS Jérémy Jean, ANSSI Dir. de thèse : Pierre-Alain Fouque, IRISA, Université de Rennes 1 Co-dir. de thèse : Patrick Derbez, IRISA, Université de Rennes 1 Remerciements Je tiens à remercier en premier lieu mes directeurs de thèse, Pierre-Alain et Patrick.