Tweakable Block Ciphers
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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]. -
Substitution-Permutation Networks, Pseudorandom Functions, and Natural Proofs∗
Substitution-permutation networks, pseudorandom functions, and natural proofs∗ Eric Miles† Emanuele Viola‡ August 20, 2015 Abstract This paper takes a new step towards closing the gap between pseudorandom func- tions (PRF) and their popular, bounded-input-length counterparts. This gap is both quantitative, because these counterparts are more efficient than PRF in various ways, and methodological, because these counterparts usually fit in the substitution-permutation network paradigm (SPN), which has not been used to construct PRF. We give several candidate PRF that are inspired by the SPN paradigm. Most Fi of our candidates are more efficient than previous ones. Our main candidates are: : 0, 1 n 0, 1 n is an SPN whose S-box is a random function on b bits given F1 { } → { } as part of the seed. We prove that resists attacks that run in time 2ǫb. F1 ≤ : 0, 1 n 0, 1 n is an SPN where the S-box is (patched) field inversion, F2 { } → { } a common choice in practical constructions. We show that is computable with F2 boolean circuits of size n logO(1) n, and that it has exponential security 2Ω(n) against · linear and differential cryptanalysis. : 0, 1 n 0, 1 is a non-standard variant on the SPN paradigm, where F3 { } → { } “states” grow in length. We show that is computable with TC0 circuits of size F3 n1+ǫ, for any ǫ> 0, and that it is almost 3-wise independent. : 0, 1 n 0, 1 uses an extreme setting of the SPN parameters (one round, F4 { } → { } one S-box, no diffusion matrix). The S-box is again (patched) field inversion. -
1 Review of Counter-Mode Encryption ¡
Comments to NIST concerning AES Modes of Operations: CTR-Mode Encryption Helger Lipmaa Phillip Rogaway Helsinki University of Technology (Finland) and University of California at Davis (USA) and University of Tartu (Estonia) Chiang Mai University (Thailand) [email protected] [email protected] http://www.tml.hut.fi/ helger http://www.cs.ucdavis.edu/ rogaway David Wagner University of California Berkeley (USA) [email protected] http://www.cs.berkeley.edu/ wagner Abstract Counter-mode encryption (“CTR mode”) was introduced by Diffie and Hellman already in 1979 [5] and is already standardized by, for example, [1, Section 6.4]. It is indeed one of the best known modes that are not standardized in [10]. We suggest that NIST, in standardizing AES modes of operation, should include CTR-mode encryption as one possibility for the next reasons. First, CTR mode has significant efficiency advantages over the standard encryption modes without weakening the security. In particular its tight security has been proven. Second, most of the perceived disadvantages of CTR mode are not valid criticisms, but rather caused by the lack of knowledge. 1 Review of Counter-Mode Encryption ¡ Notation. Let EK X ¢ denote the encipherment of an n-bit block X using key K and a block cipher E. For concreteness £ ¤ we assume that E £ AES, so n 128. If X is a nonempty string and i is a nonnegative integer, then X i denotes ¥ the ¥ X -bit string that one gets by regarding X as a nonnegative number (written in binary, most significant bit first), X ¦ ¥ ¥ adding i to this number, taking the result modulo 2 ¦ , and converting this number back into an X -bit string. -
Patent-Free Authenticated-Encryption As Fast As OCB
Patent-Free Authenticated-Encryption As Fast As OCB Ted Krovetz Computer Science Department California State University Sacramento, California, 95819 USA [email protected] Abstract—This paper presents an efficient authenticated encryp- VHASH hash family [4]. The resulting authenticated encryp- tion construction based on a universal hash function and block tion scheme peaks at 12.8 cpb, while OCB peaks at 13.9 cpb in cipher. Encryption is achieved via counter-mode while authenti- our experiments. The paper closes with a performance com- cation uses the Wegman-Carter paradigm. A single block-cipher parison of several well-known authenticated encryption algo- key is used for both operations. The construction is instantiated rithms [6]. using the hash functions of UMAC and VMAC, resulting in authenticated encryption with peak performance about ten per- cent slower than encryption alone. II. SECURITY DEFINITIONS We adopt the notions of security from [7], and summarize Keywords- Authenticated encryption, block-cipher mode-of- them less formally here. An authenticated encryption with as- operation, AEAD, UMAC, VMAC. sociated data (AEAD) scheme is a triple S = (K,E,D), where K is a set of keys, and E and D are encryption and decryption I. INTRODUCTION functions. Encryption occurs by computing E(k,n,h,p,f), which Traditionally when one wanted to both encrypt and authen- returns (c,t), for key k, nonce n, header h, plaintext m and ticate communications, one would encrypt the message under footer f. Ciphertext c is the encryption of p, and tag t authenti- one key and authenticate the resulting ciphertext under a sepa- cates h, c and f. -
Modes of Operation for Compressed Sensing Based Encryption
Modes of Operation for Compressed Sensing based Encryption DISSERTATION zur Erlangung des Grades eines Doktors der Naturwissenschaften Dr. rer. nat. vorgelegt von Robin Fay, M. Sc. eingereicht bei der Naturwissenschaftlich-Technischen Fakultät der Universität Siegen Siegen 2017 1. Gutachter: Prof. Dr. rer. nat. Christoph Ruland 2. Gutachter: Prof. Dr.-Ing. Robert Fischer Tag der mündlichen Prüfung: 14.06.2017 To Verena ... s7+OZThMeDz6/wjq29ACJxERLMATbFdP2jZ7I6tpyLJDYa/yjCz6OYmBOK548fer 76 zoelzF8dNf /0k8H1KgTuMdPQg4ukQNmadG8vSnHGOVpXNEPWX7sBOTpn3CJzei d3hbFD/cOgYP4N5wFs8auDaUaycgRicPAWGowa18aYbTkbjNfswk4zPvRIF++EGH UbdBMdOWWQp4Gf44ZbMiMTlzzm6xLa5gRQ65eSUgnOoZLyt3qEY+DIZW5+N s B C A j GBttjsJtaS6XheB7mIOphMZUTj5lJM0CDMNVJiL39bq/TQLocvV/4inFUNhfa8ZM 7kazoz5tqjxCZocBi153PSsFae0BksynaA9ZIvPZM9N4++oAkBiFeZxRRdGLUQ6H e5A6HFyxsMELs8WN65SCDpQNd2FwdkzuiTZ4RkDCiJ1Dl9vXICuZVx05StDmYrgx S6mWzcg1aAsEm2k+Skhayux4a+qtl9sDJ5JcDLECo8acz+RL7/ ovnzuExZ3trm+O 6GN9c7mJBgCfEDkeror5Af4VHUtZbD4vALyqWCr42u4yxVjSj5fWIC9k4aJy6XzQ cRKGnsNrV0ZcGokFRO+IAcuWBIp4o3m3Amst8MyayKU+b94VgnrJAo02Fp0873wa hyJlqVF9fYyRX+couaIvi5dW/e15YX/xPd9hdTYd7S5mCmpoLo7cqYHCVuKWyOGw ZLu1ziPXKIYNEegeAP8iyeaJLnPInI1+z4447IsovnbgZxM3ktWO6k07IOH7zTy9 w+0UzbXdD/qdJI1rENyriAO986J4bUib+9sY/2/kLlL7nPy5Kxg3 Et0Fi3I9/+c/ IYOwNYaCotW+hPtHlw46dcDO1Jz0rMQMf1XCdn0kDQ61nHe5MGTz2uNtR3bty+7U CLgNPkv17hFPu/lX3YtlKvw04p6AZJTyktsSPjubqrE9PG00L5np1V3B/x+CCe2p niojR2m01TK17/oT1p0enFvDV8C351BRnjC86Z2OlbadnB9DnQSP3XH4JdQfbtN8 BXhOglfobjt5T9SHVZpBbzhDzeXAF1dmoZQ8JhdZ03EEDHjzYsXD1KUA6Xey03wU uwnrpTPzD99cdQM7vwCBdJnIPYaD2fT9NwAHICXdlp0pVy5NH20biAADH6GQr4Vc -
Secret-Key Encryption Introduction
Secret-Key Encryption Introduction • Encryption is the process of encoding a message in such a way that only authorized parties can read the content of the original message • History of encryption dates back to 1900 BC • Two types of encryption • secret-key encryption : same key for encryption and decryption • pubic-key encryption : different keys for encryption and decryption • We focus on secret-key encryption in this chapter Substitution Cipher • Encryption is done by replacing units of plaintext with ciphertext, according to a fixed system. • Units may be single letters, pairs of letters, triplets of letters, mixtures of the above, and so forth • Decryption simply performs the inverse substitution. • Two typical substitution ciphers: • monoalphabetic - fixed substitution over the entire message • Polyalphabetic - a number of substitutions at different positions in the message Monoalphabetic Substitution Cipher • Encryption and decryption Breaking Monoalphabetic Substitution Cipher • Frequency analysis is the study of the frequency of letters or groups of letters in a ciphertext. • Common letters : T, A, E, I, O • Common 2-letter combinations (bigrams): TH, HE, IN, ER • Common 3-letter combinations (trigrams): THE, AND, and ING Breaking Monoalphabetic Substitution Cipher • Letter Frequency Analysis results: Breaking Monoalphabetic Substitution Cipher • Bigram Frequency Analysis results: Breaking Monoalphabetic Substitution Cipher • Trigram Frequency analysis results: Breaking Monoalphabetic Substitution Cipher • Applying the partial mappings… Data Encryption Standard (DES) • DES is a block cipher - can only encrypt a block of data • Block size for DES is 64 bits • DES uses 56-bit keys although a 64-bit key is fed into the algorithm • Theoretical attacks were identified. None was practical enough to cause major concerns. -
The Evolution of Authenticated Encryption
The Evolution of Authenticated Encryption Phillip Rogaway University of California, Davis, USA Those who’ve worked with me on AE: Mihir Bellare Workshop on Real-World Cryptography John Black Thursday, 10 January 2013 Ted Krovetz Stanford, California, USA Chanathip Namprempre Tom Shrimpton David Wagner 1/40 Traditional View (~2000) Of Symmetric Goals K K Sender Receiver Privacy Authenticity (confidentiality) (data-origin authentication) Encryption Authenticated Encryption Message scheme Achieve both of these aims Authentication Code (MAC) IND-CPA [Goldwasser, Micali 1982] Existential-unforgeability under ACMA [Bellare, Desai, Jokipii, R 1997] [Goldwasser, Micali, Rivest 1984, 1988], [Bellare, Kilian, R 1994], [Bellare, Guerin, R 1995] 2/40 Needham-Schroeder Protocol (1978) Attacked by Denning-Saco (1981) Practioners never saw a b IND-CPA as S encryption’s goal A . B . NA {N . B . s . {s . A} } 1 A b a 2 a b {s . A} A 3 b B 4 {NB}s 5 {NB -1 }s 3/40 Add redundancy No authenticity for any S = f (P) CBC ~ 1980 Doesn’t work Beyond CBC MAC: regardless of how you compute unkeyed checksums don’t work even the (unkeyed) checksum S = R(P1, …, Pn) with IND-CCA or NM-CPA schemes (Wagner) [An, Bellare 2001] 4/40 Add more arrows PCBC 1982 Doesn’t work See [Yu, Hartman, Raeburn 2004] The Perils of Unauthenticated Encryption: Kerberos Version 4 for real-world attacks 5/40 Add yet more stuff iaPCBC [Gligor, Donescu 1999] Doesn’t work Promptly broken by Jutla (1999) & Ferguson, Whiting, Kelsey, Wagner (1999) 6/40 Emerging understanding that: - We’d like -
Optimizing Authenticated Encryption Algorithms
Masaryk University Faculty of Informatics Optimizing authenticated encryption algorithms Master’s Thesis Ondrej Mosnáček Brno, Fall 2017 Masaryk University Faculty of Informatics Optimizing authenticated encryption algorithms Master’s Thesis Ondrej Mosnáček Brno, Fall 2017 This is where a copy of the official signed thesis assignment and a copy ofthe Statement of an Author is located in the printed version of the document. Declaration Hereby I declare that this paper is my original authorial work, which I have worked out on my own. All sources, references, and literature used or excerpted during elaboration of this work are properly cited and listed in complete reference to the due source. Ondrej Mosnáček Advisor: Ing. Milan Brož i Acknowledgement I would like to thank my advisor, Milan Brož, for his guidance, pa- tience, and helpful feedback and advice. Also, I would like to thank my girlfriend Ludmila, my family, and my friends for their support and kind words of encouragement. If I had more time, I would have written a shorter letter. — Blaise Pascal iii Abstract In this thesis, we look at authenticated encryption with associated data (AEAD), which is a cryptographic scheme that provides both confidentiality and integrity of messages within a single operation. We look at various existing and proposed AEAD algorithms and compare them both in terms of security and performance. We take a closer look at three selected candidate families of algorithms from the CAESAR competition. Then we discuss common facilities provided by the two most com- mon CPU architectures – x86 and ARM – that can be used to implement cryptographic algorithms efficiently. -
On the Security of CTR + CBC-MAC NIST Modes of Operation – Additional CCM Documentation
On the Security of CTR + CBC-MAC NIST Modes of Operation { Additional CCM Documentation Jakob Jonsson? jakob [email protected] Abstract. We analyze the security of the CTR + CBC-MAC (CCM) encryption mode. This mode, proposed by Doug Whiting, Russ Housley, and Niels Ferguson, combines the CTR (“counter”) encryption mode with CBC-MAC message authentication and is based on a block cipher such as AES. We present concrete lower bounds for the security of CCM in terms of the security of the underlying block cipher. The conclusion is that CCM provides a level of privacy and authenticity that is in line with other proposed modes such as OCB. Keywords: AES, authenticated encryption, modes of operation. Note: A slightly different version of this paper will appear in the Proceedings from Selected Areas of Cryptography (SAC) 2002. 1 Introduction Background. Block ciphers are popular building blocks in cryptographic algo rithms intended to provide information services such as privacy and authenticity. Such block-cipher based algorithms are referred to as modes of operation. Exam ples of encryption modes of operation are Cipher Block Chaining Mode (CBC) [23], Electronic Codebook Mode (ECB) [23], and Counter Mode (CTR) [9]. Since each of these modes provides privacy only and not authenticity, most applica tions require that the mode be combined with an authentication mechanism, typically a MAC algorithm [21] based on a hash function such as SHA-1 [24]. For example, a popular cipher suite in SSL/TLS [8] combines CBC mode based on Triple-DES [22] with the MAC algorithm HMAC [26] based on SHA-1. -
AUTHENTICATED ENCRYPTION in HARDWARE by Milind M. Parelkar
AUTHENTICATED ENCRYPTION IN HARDWARE by Milind M. Parelkar A Thesis Submitted to the Graduate Faculty of George Mason University in Partial Ful¯llment of the the Requirements for the Degree of Master of Science Electrical and Computer Engineering Committee: Dr. Kris Gaj, Thesis Director Dr. William Sutton Dr. Peter Pachowicz Andre Manitius, Chairman, Department of Electrical and Computer Engineering Lloyd J. Gri±ths, Dean, School of Information Technology and Engineering Date: Fall 2005 George Mason University Fairfax, VA Authenticated Encryption in Hardware A thesis submitted in partial ful¯llment of the requirements for the degree of Master of Science at George Mason University By Milind M. Parelkar Bachelor of Engineering University of Mumbai(Bombay), India, 2002 Director: Dr. Kris Gaj, Associate Professor Department of Electrical and Computer Engineering Fall 2005 George Mason University Fairfax, VA ii Copyright °c 2005 by Milind M. Parelkar All Rights Reserved iii Acknowledgments I would like to thank Dr. Kris Gaj for helping me throughout the course of this research. Special thanks to Pawel Chodowiec, without whose help, it would have been very di±cult to come up with good results, on time. iv Table of Contents Page Abstract . xii 1 Authenticated Encryption - Introduction and Motivation . 1 1.1 Cryptographic Goals . 1 1.2 What is Authenticated - Encryption? . 2 1.3 Target Applications for Authenticated - Encryption . 7 1.3.1 Encryption and Authentication of FPGA Bitstream . 7 1.3.2 Authenticated - Encryption in 802.11 Wireless LANs . 11 1.4 Authentication Techniques . 12 1.4.1 Hash Functions . 12 1.4.2 Message Authentication Codes (MACs) . -
Lecture Notes in Computer Science 6841 Commenced Publication in 1973 Founding and Former Series Editors: Gerhard Goos, Juris Hartmanis, and Jan Van Leeuwen
Lecture Notes in Computer Science 6841 Commenced Publication in 1973 Founding and Former Series Editors: Gerhard Goos, Juris Hartmanis, and Jan van Leeuwen Editorial Board David Hutchison Lancaster University, UK Takeo Kanade Carnegie Mellon University, Pittsburgh, PA, USA Josef Kittler University of Surrey, Guildford, UK Jon M. Kleinberg Cornell University, Ithaca, NY, USA Alfred Kobsa University of California, Irvine, CA, USA Friedemann Mattern ETH Zurich, Switzerland John C. Mitchell Stanford University, CA, USA Moni Naor Weizmann Institute of Science, Rehovot, Israel Oscar Nierstrasz University of Bern, Switzerland C. Pandu Rangan Indian Institute of Technology, Madras, India Bernhard Steffen TU Dortmund University, Germany Madhu Sudan Microsoft Research, Cambridge, MA, USA Demetri Terzopoulos University of California, Los Angeles, CA, USA Doug Tygar University of California, Berkeley, CA, USA Gerhard Weikum Max Planck Institute for Informatics, Saarbruecken, Germany Phillip Rogaway (Ed.) Advances in Cryptology – CRYPTO 2011 31st Annual Cryptology Conference Santa Barbara, CA, USA, August 14-18, 2011 Proceedings 13 Volume Editor Phillip Rogaway University of California Department of Computer Science Davis, CA 95616, USA E-mail: [email protected] ISSN 0302-9743 e-ISSN 1611-3349 ISBN 978-3-642-22791-2 e-ISBN 978-3-642-22792-9 DOI 10.1007/978-3-642-22792-9 Springer Heidelberg Dordrecht London New York Library of Congress Control Number: 2011932695 CR Subject Classification (1998): E.3, G.2.1, F.2.1-2, D.4.6, K.6.5, C.2, J.1 LNCS Sublibrary: SL 4 – Security and Cryptology © International Association for Cryptologic Research 2011 This work is subject to copyright. -
Secure Image Transferring Using Asymmetric Crypto System
Oo Khet Khet Khaing et al.; International Journal of Advance Research and Development (Volume 4, Issue 9) Available online at: www.ijarnd.com Secure image transferring using asymmetric crypto system Khet Khet Khaing Oo1, Yan Naung Soe2, Yi Mar Myint3 1,2University of Computer Studies, Myitkyina, Myanmar 3University of Computer Studies, Monywa, Myanmar ABSTRACT defined as Plain Text. The message that cannot be understood by anyone or meaningless message is what we call as Cipher Nowadays, with the growth of technology, security is an Text. Encryption is the process of converting plaintext into important issue in communication. In many applications, the ciphertext with a key. A Key is a numeric or alphanumeric text transmission of data (massage, image and so on) is needed to or maybe a special symbol. Decryption is a reverse process of provide security against from preventing unauthorized users. encryption in which original message is retrieved from the Cryptography is a technique that provides secure ciphertext. Encryption takes place at the sender end and communication. The two widely accepted and used Decryption takes place at the receiver end. cryptographic methods are symmetric and asymmetric. There are so many different techniques should be used to protect A system or product that provides encryption and decryption is confidential image data from unauthorized access. This called cryptosystem. Cryptosystem uses encryption algorithms system provides secure image transmission between sender that determine how simple or complex the encryption process and receiver. This system uses Optimal Asymmetric will be, the necessary software component, and the key Encryption Padding (OAEP) with RSA encryption algorithm (usually a long string of bits), which works with the algorithm to provide security during transmission.