DOCSLIB.ORG

Modified LOKI97 Algorithm Based on DNA Technique and Permutation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Modified LOKI97 Algorithm Based on DNA Technique and Permutation 76 المجلة العراقية لتكنولوجيا المعلومات.. المجلد. 8 - العدد. 2 - 2018 Modified LOKI97 Algorithm Based on DNA Technique and Permutation Assist. Prof. Dr. Alaa Kadhim M.Sc. Shahad Husham University of Technology / Computer science department E-mail: [email protected] ABSTRACT As is common, in the cryptography, that any encryption algorithm may be vulnerable to breakage, but that conflicts with the most significant goal of any encryption algorithm, which is to conserve sensitive information that will be transmitted via an unsafe channel, therefore the algorithms must be designed to be resistant against the attacks and adversaries, by increasing the complexity of some internal functions, raised the number of rounds or using some techniques such as artificial intelligence to develop this algorithm. In this paper, has been proposed an approach to develop the classical LOKI97 algorithm by enhancement some of its internal functions for increasing the confusion and diffusion to possess resistance against the attacker. 77 المجلة العراقية لتكنولوجيا المعلومات.. المجلد. 8 - العدد. 2 - 2018 المستخلص كما هو شائع في التشفير ان خوارزميه التشفير قد تكون عرضه للكسر ولكن هذا يتعارض مع الهدف اﻻكثر اهميه في خوارزميه التشفير والتهيئه لحمايه المعلومات الحساسه في الرساله تنتقل ضمن قناه غير امنه ولذلك يجب ان تكون الخوارزميه مصممه لتكون مقاومه ضد محاوﻻت الكسر من خﻻل زياده التعقيد ببعض الوضائف الداخليه وزياده عدد الدورات واستخدام بعض التقنيات الذكاء اﻻصطناعي لتطويرهذه الخوارزمية. في هذا البحث , تم اقتراح تطوير خوارزمية LOKI97 , من خﻻل تطوير بعض دوالها لزيادة درجة تعقيدها مما يجعلها تمتلك أرتباك وانتشار عالي , لتكون أكثر قوة ضد اﻻخت ارق . Keywords: Block Cipher, LOKI97, Permutation, DNA Technique 1. Introduction Maintaining and protecting information security has been and still which is the main objective of information security programs such the large organizations and companies spend thousands of dollars and working hours to maintain their information systems. Since attacks are a daily occurrence on their sources of information and systems as well as the evolution of these attacks, the need for information security development goes hand in hand with the evolution of these attacks [1]. In the current era, it became clear that a most important means of protecting sensitive information and accurate data is using cryptography. The cryptography is considered a powerful and effective way to protect information as well as send it quickly and 78 المجلة العراقية لتكنولوجيا المعلومات.. المجلد. 8 - العدد. 2 - 2018 to check the process of sending and receiving it correctly. Where the cryptography can now be regarded as the cornerstone of his peace of the computers and telecommunications because it provides the secure services needed by any party wishing to secure its digital data [2]. 2. LOKI97 Overview [3] The family of a block cipher of (Loki89, Loki91) is designed to be as replacing of data encryption standard (DES) algorithm, and it is very similar to DES in its structure. LOKI97 is one member of the LOKI family, designing by Lawrie Brown. This algorithm, is a new Feistel cipher of 16 round and using a data of 128 bits by employ a complex non-linear function (F). It is using 128, 192, or 256-bit keys. The LOKI97 is designing as a development of Loki 91, by increasing the number of rounds up to 16 and increase the data input from 64-bits to 128-bits, and made the function (F-function) more complicated that is using also in the key schedule. The following figure showed the main F-function of LOKI97. 79 المجلة العراقية لتكنولوجيا المعلومات.. المجلد. 8 - العدد. 2 - 2018 3. The Proposed Work In LOKI89,91 some weaknesses appeared such as key scheduling that have been handled in LOKI97, it has also been increasing the length of the block in addition to the complexity of the F-function and use this nonlinear complex function in its key scheduler. In LOKI97 algorithm, there are some fragility in internal functions component. In this paper, the proposal has 80 المجلة العراقية لتكنولوجيا المعلومات.. المجلد. 8 - العدد. 2 - 2018 improved some functions which are keyed-permutation, permutation function and S-box. The proposal of developing the LOKI97 algorithms is consisting of five internal functions which were included two layers of S- boxes (AES S-box). The first and second phases were a dynamic shifting function and a dynamic DNA addition function. The dynamic shift function that used in this proposal, is featured by awarding a high diffusion. As for the DNA technique, has been used because it is characterized by many advantages such as its privilege of huge capacity in the data storage, in addition to its speed, where the conventional computers can perform nearly (millions of instructions per second), while, as clarified by Adelman, DNA strands has made the computations at a speed of about 10 ^ 9 or better, which can be said to be about 100 times faster than quickest computers. The last phase in the proposed algorithm is the LOKI- permutation function, which is the same permutation function, has been used in the classical LOKI97 algorithm. The following presented figure (2) illustrated the proposed work. 81 المجلة العراقية لتكنولوجيا المعلومات.. المجلد. 8 - العدد. 2 - 2018 3.1 Dynamic Shift Function The keyed permutation function which located in the main function of the LOKI97 algorithm has been replaced by the dynamic shift function. The dynamic circular left shift function is granted a high diffusion to the input bits, it receives 64 bits of input block and 32 bits of a key block then producing a cipher text of 64 bits as an output. It begins by dividing the input block to eight blocks of the length (8 bits), and this division is also done on the key block to gain eight blocks of length 4 bits. Then, every key block will convert from binary code to the equivalent 82 المجلة العراقية لتكنولوجيا المعلومات.. المجلد. 8 - العدد. 2 - 2018 decimal number, and setting every number as a switch key to the input blocks, this means, the shift will apply on every block of the input to the left direction according to the number of the equivalent key block. 83 المجلة العراقية لتكنولوجيا المعلومات.. المجلد. 8 - العدد. 2 - 2018 For example, if the input block was (10010110), the key block is (1001), convert the key block to decimal to be (9), this means performs the left shifting process on the block (9th times). 84 المجلة العراقية لتكنولوجيا المعلومات.. المجلد. 8 - العدد. 2 - 2018 So, the block will be (00101101). When applied the inverse algorithm to retrieve the original block, the shifting process performs in the right direction so the block (00101101) will shift as the key block (1001), (9th times to the right) to be (10010110). 3.2 Dynamic DNA Addition Function: In this proposal has been dispensed with the idea of the compression, by deleting the expansion function in the LOKI97 standard algorithm that gives a 96 bits as an input to this S-box. So the expansion function will have replaced by the dynamic DNA addition function. The dynamic DNA addition function is a proposed function designed to be depend on the dynamic key. This function will have received a key of 32 bits, this key will be subjected to several processing to suit the several stages of this function. The function works according to several steps, in every step will use a key of different length, firstly, the input block is a 64 bits is divided into 32 blocks of (2 bits), then these blocks will be transformed to the equivalent decimal number. These numbers are compensated according to the proposed specific table by using the key. As for the key, as mentioned above, the key will be processing many times. At the beginning, the 32 bits of the key will be expanded to 64 bits by performing the Xor operation between all two adjacent bits (the last bit will be Xor with 0) to 85 المجلة العراقية لتكنولوجيا المعلومات.. المجلد. 8 - العدد. 2 - 2018 get an additional 32 bits, then will be concatenated them with the bits of the original key to form the 64 bits at the end. Then, the second process is splitting the 64 bits of the key into two arrays (odd and even arrays of the 32 bits to each array) and perform the Xor operation between them in gaining the 32 bits and concatenating them with the key of 64 bits to getting 96 bits. In the first stage, the key of 96 bits will be used in the first step of the enciphering, which is dividing the 96 bits into 32 blocks of (3 bits) and transforming these blocks to equivalent decimal number to construct the decimal key blocks. Now, matching the decimal input blocks with the rows of the proposed DNA table (1), while the decimal key blocks will be matched with column of the same table and compensation the resulting code to getting a new sequence of 32 DNA codes. While in the second stage, the key of (64 bits) was used here. It will perform the division of the key into 32 blocks of the length 2 bits, then, coded the 32 blocks by DNA classic codes, which that the 00 is coded to the (A) and 01,10,11 will coded in C, G, T respectively, then will be getting a sequence of DNA code of the key. In the third stage, the DNA-addition operation the table (2) was performed on the two DNA sequences of the input and the key. 86 المجلة العراقية لتكنولوجيا المعلومات.. المجلد. 8 - العدد. 2 - 2018 87 المجلة العراقية لتكنولوجيا المعلومات.. المجلد. 8 - العدد. 2 - 2018 Algorithm (3): Dynamic DNA addition Algorithm Input: 64 bits as input block.
Load more

Recommended publications
  • The Long Road to the Advanced Encryption Standard
    The Long Road to the Advanced Encryption Standard Jean-Luc Cooke CertainKey Inc. [email protected], http://www.certainkey.com/˜jlcooke Abstract 1 Introduction This paper will start with a brief background of the Advanced Encryption Standard (AES) process, lessons learned from the Data Encryp- tion Standard (DES), other U.S. government Two decades ago the state-of-the-art in cryptographic publications and the fifteen first the private sector cryptography was—we round candidate algorithms. The focus of the know now—far behind the public sector. presentation will lie in presenting the general Don Coppersmith’s knowledge of the Data design of the five final candidate algorithms, Encryption Standard’s (DES) resilience to and the specifics of the AES and how it dif- the then unknown Differential Cryptanaly- fers from the Rijndael design. A presentation sis (DC), the design principles used in the on the AES modes of operation and Secure Secure Hash Algorithm (SHA) in Digital Hash Algorithm (SHA) family of algorithms Signature Standard (DSS) being case and will follow and will include discussion about point[NISTDSS][NISTDES][DC][NISTSHA1]. how it is directly implicated by AES develop- ments. The selection and design of the DES was shrouded in controversy and suspicion. This very controversy has lead to a fantastic acceler- Intended Audience ation in private sector cryptographic advance- ment. So intrigued by the NSA’s modifica- tions to the Lucifer algorithm, researchers— This paper was written as a supplement to a academic and industry alike—powerful tools presentation at the Ottawa International Linux in assessing block cipher strength were devel- Symposium.
    [Show full text]
  • 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.
    [Show full text]
  • Perbandingan Algoritma LOKI, GOST, Dan Blowfish Yang Merupakan Kelompok Dari Algorima Block Cipher
    Perbandingan Algoritma LOKI, GOST, dan Blowfish yang Merupakan Kelompok dari Algorima Block Cipher Yongke Yoswara - 13508034 Program Studi Teknik Informatika Sekolah Teknik Elektro dan Informatika Institut Teknologi Bandung, Jl. Ganesha 10 Bandung 40132, Indonesia [email protected] Abstrak—Saat ini begitu banyak algoritma kriptografi karakter. Namun dengan semakin banyaknya penggunaan modern. Algoritma kriptografi modern beroperasi dalam komputer dijital, maka kriptografi modern beroperasi mode bit (berbeda dengan algoritma kriptografi klasik yang dalam mode bit (satuan terkecil dalam dunia dijital). beroperasi pada mode karakter). Ada 2 jenis algoritma yang Walaupun menggunakan mode bit, algoritma dalam beroperasi pada mode bit, yaitu stream cipher dan block cipher. Dalam block cipher, ada 5 prinsip perancangan, yaitu kriptografi modern tetap menggunakan prinsip substitusi : Prinsip Confusion dan Diffusion, Cipher berulang, dan transposisi yang sebenarnya telah digunakan sejak Jaringan Feistel, Kunci lemah, Kotak-S. Jaringan Feistel kriptografi klasik. banyak dipakai pada algoritma DES, LOKI, GOST, Feal, Algoritma kriptografi modern dapat dibagi menjadi Lucifer, Blowfish, dan lain-lain karena model ini bersifat dua, yaitu algoritma simetri dan kunci public. Algoritma reversible untuk proses dekripsi dan enkripsi. Sifat simetri adalah algoritma yang menggunakan kunci yang reversible ini membuat kita tidak perlu membuat algoritma baru untuk mendekripsi cipherteks menjadi plainteks. sama untuk proses enkripsi dan dekripsi. Algoritma simetri yang beroperasi pada mode bit itu sendiri dapat Kata Kunci—block cipher, jaringan feistel, reversible dibagi menjadi 2 jenis, yaitu stream cipher dan block cipher. Stream cipher adalah algoritma kriptografi yang beroperasi dalam bentuk bit tunggal. Sedangkan block I. PENDAHULUAN cipher beroperasi dalam bentuk blok-blok bit. Ada banyak jenis algoritma yang menggunakan stream Sekarang ini, teknologi berkembang sangat pesat.
    [Show full text]
  • Bahles of Cryptographic Algorithms
    Ba#les of Cryptographic Algorithms: From AES to CAESAR in Soware & Hardware Kris Gaj George Mason University Collaborators Joint 3-year project (2010-2013) on benchmarking cryptographic algorithms in software and hardware sponsored by software FPGAs FPGAs/ASICs ASICs Daniel J. Bernstein, Jens-Peter Kaps Patrick Leyla University of Illinois George Mason Schaumont Nazhand-Ali at Chicago University Virginia Tech Virginia Tech CERG @ GMU hp://cryptography.gmu.edu/ 10 PhD students 4 MS students co-advised by Kris Gaj & Jens-Peter Kaps Outline • Introduction & motivation • Cryptographic standard contests Ø AES Ø eSTREAM Ø SHA-3 Ø CAESAR • Progress in evaluation methods • Benchmarking tools • Open problems Cryptography is everywhere We trust it because of standards Buying a book on-line Withdrawing cash from ATM Teleconferencing Backing up files over Intranets on remote server Cryptographic Standards Before 1997 Secret-Key Block Ciphers 1977 1999 2005 IBM DES – Data Encryption Standard & NSA Triple DES Hash Functions 1993 1995 2003 NSA SHA-1–Secure Hash Algorithm SHA SHA-2 1970 1980 1990 2000 2010 time Cryptographic Standard Contests IX.1997 X.2000 AES 15 block ciphers → 1 winner NESSIE I.2000 XII.2002 CRYPTREC XI.2004 V.2008 34 stream 4 HW winners eSTREAM ciphers → + 4 SW winners XI.2007 X.2012 51 hash functions → 1 winner SHA-3 IV.2013 XII.2017 57 authenticated ciphers → multiple winners CAESAR 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 time Why a Contest for a Cryptographic Standard? • Avoid back-door theories • Speed-up
    [Show full text]
  • AES); Cryptography; Cryptanaly- the Candidates
    Volume 104, Number 5, September–October 1999 Journal of Research of the National Institute of Standards and Technology [J. Res. Natl. Inst. Stand. Technol. 104, 435 (1999)] Status Report on the First Round of the Development of the Advanced Encryption Standard Volume 104 Number 5 September–October 1999 James Nechvatal, Elaine Barker, In 1997, the National Institute of Standards (MARS, RC6, Rijndael, Serpent and Donna Dodson, Morris Dworkin, and Technology (NIST) initiated a pro- Twofish) as finalists. The research results James Foti, and Edward Roback cess to select a symmetric-key encryption and rationale for the selection of the fi- algorithm to be used to protect sensitive nalists are documented in this report. National Institute of Standards and (unclassified) Federal information in The five finalists will be the subject of furtherance of NIST’s statutory responsi- further study before the selection of one or Technology, bilities. In 1998, NIST announced the more of these algorithms for inclusion in Gaithersburg, MD 20899-0001 acceptance of 15 candidate algorithms the Advanced Encryption Standard. and requested the assistance of the crypto- Key words: Advanced Encryption graphic research community in analyzing Standard (AES); cryptography; cryptanaly- the candidates. This analysis included an sis; cryptographic algorithms; initial examination of the security and encryption. efficiency characteristics for each al- gorithm. NIST has reviewed the results Accepted: August 11, 1999 of this research and selected five algorithms Available online: http://www.nist.gov/jres Contents 2.4.1.2 Other Architectural Issues ...........442 1. Overview of the Development Process for the Advanced 2.4.1.3 Software .........................442 Encryption Standard and Summary of Round 1 2.4.2 Measured Speed on General Platforms.........442 Evaluations ......................................
    [Show full text]
  • Performance Comparison of the AES Submissions
    Performance Comparison of the AES Submissions Bruce Schneier∗ John Kelseyy Doug Whitingz David Wagnerx Chris Hall{ Niels Ferguson k Version 2.0 February 1, 1999 1 Introduction of the algorithms have different performance char- acteristics for different key lengths. The results are The principal goal guiding the design of any encryp- summarized in Table 1. tion algorithm must be security. In the real world, Nine algorithms|CAST-256, Crypton, DFC, however, performance and implementation cost are E2, Frog, HPC, Mars, RC6, and Serpent|are com- always of concern. Making the assumption that the pletely independent of key length. Two algorithms| major AES candidates are secure (a big assumption, Loki97 and Twofish—encrypt and decrypt indepen- to be sure, but one that is best dealt with in an- dent of key length, but take different times to set up other paper), the most important properties the al- different-size keys1. Twofish takes longer to set up gorithms will be judged on will be the performance a longer key, while Loki97 actually takes less time and cost of implementation. to set up a longer key than it does to set up a In this paper, we will completely ignore secu- shorter key. Four algorithms|DEAL, Magenta, Ri- rity. Instead, we will compare the performance of jndael, and SAFER+|encrypt and decrypt at dif- the leading AES candidates on a variety of common ferent speeds, depending on key length. platforms: 32-bit CPUs, 64-bit CPUs, cheap 8-bit In this paper, we will concentrate on key setup smart-card CPUs, and dedicated hardware.
    [Show full text]
  • Cryptanalysis of Symmetric-Key Primitives Based on the AES Block Cipher Jérémy Jean
    Cryptanalysis of Symmetric-Key Primitives Based on the AES Block Cipher Jérémy Jean To cite this version: Jérémy Jean. Cryptanalysis of Symmetric-Key Primitives Based on the AES Block Cipher. Cryp- tography and Security [cs.CR]. Ecole Normale Supérieure de Paris - ENS Paris, 2013. English. tel- 00911049 HAL Id: tel-00911049 https://tel.archives-ouvertes.fr/tel-00911049 Submitted on 28 Nov 2013 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. Université Paris Diderot École Normale Supérieure (Paris 7) Équipe Crypto Thèse de doctorat Cryptanalyse de primitives symétriques basées sur le chiffrement AES Spécialité : Informatique présentée et soutenue publiquement le 24 septembre 2013 par Jérémy Jean pour obtenir le grade de Docteur de l’Université Paris Diderot devant le jury composé de Directeur de thèse : Pierre-Alain Fouque (Université de Rennes 1, France) Rapporteurs : Anne Canteaut (INRIA, France) Henri Gilbert (ANSSI, France) Examinateurs : Arnaud Durand (Université Paris Diderot, France) Franck Landelle (DGA, France) Thomas Peyrin (Nanyang Technological University, Singapour) Vincent Rijmen (Katholieke Universiteit Leuven, Belgique) Remerciements Je souhaite remercier toutes les personnes qui ont contribué de près ou de loin à mes trois années de thèse.
    [Show full text]
  • Efficiency Testing of ANSI C Implementations of Round 1Candidate Algorithms for The
    Efficiency Testing of ANSI C Implementations of Round1 Candidate Algorithms for the Advanced Encryption Standard Lawrence E. Bassham III Computer Security Division Information Technology Laboratory National Institute of Standards and Technology October 13, 1999 ii 1. INTRODUCTION .................................................................................................................................................. 1 2. SCOPE..................................................................................................................................................................... 1 3. METHODOLOGY ................................................................................................................................................. 1 3.1 TIMING PROGRAM ............................................................................................................................................... 3 3.2 CYCLE COUNTING PROGRAM .............................................................................................................................. 3 4. OBSERVATIONS................................................................................................................................................... 4 4.1 GENERAL............................................................................................................................................................. 4 4.2 ALGORITHM SPECIFIC.........................................................................................................................................
    [Show full text]
  • Statistical Cryptanalysis of Block Ciphers
    Statistical Cryptanalysis of Block Ciphers THESE` N◦ 3179 (2004) PRESENT´ EE´ A` LA FACULTE´ INFORMATIQUE & COMMUNICATIONS Institut de syst`emes de communication SECTION DES SYSTEMES` DE COMMUNICATION ECOLE´ POLYTECHNIQUE FED´ ERALE´ DE LAUSANNE POUR L'OBTENTION DU GRADE DE DOCTEUR ES` SCIENCES PAR Pascal JUNOD ing´enieur informaticien diplom´e EPF de nationalit´e suisse et originaire de Sainte-Croix (VD) accept´ee sur proposition du jury: Prof. Emre Telatar (EPFL), pr´esident du jury Prof. Serge Vaudenay (EPFL), directeur de th`ese Prof. Jacques Stern (ENS Paris, France), rapporteur Prof. em. James L. Massey (ETHZ & Lund University, Su`ede), rapporteur Prof. Willi Meier (FH Aargau), rapporteur Prof. Stephan Morgenthaler (EPFL), rapporteur Lausanne, EPFL 2005 to Mimi and Chlo´e Acknowledgments First of all, I would like to warmly thank my supervisor, Prof. Serge Vaude- nay, for having given to me such a wonderful opportunity to perform research in a friendly environment, and for having been the perfect supervisor that every PhD would dream of. I am also very grateful to the president of the jury, Prof. Emre Telatar, and to the reviewers Prof. em. James L. Massey, Prof. Jacques Stern, Prof. Willi Meier, and Prof. Stephan Morgenthaler for having accepted to be part of the jury and for having invested such a lot of time for reviewing this thesis. I would like to express my gratitude to all my (former and current) col- leagues at LASEC for their support and for their friendship: Gildas Avoine, Thomas Baign`eres, Nenad Buncic, Brice Canvel, Martine Corval, Matthieu Finiasz, Yi Lu, Jean Monnerat, Philippe Oechslin, and John Pliam.
    [Show full text]
  • Beecrypt Ciphers: Speed by Data Length P3-1000-Debian-Etch Beecrypt Ciphers: Speed by Data Length Ath-2000-Debian-Etch Beecrypt Ciphers: Speed by Data Length 5 16 30
    p2-300-debian-etch libgcrypt Ciphers: Absolute Time by Data Length p3-1000-debian-etch libgcrypt Ciphers: Absolute Time by Data Length ath-2000-debian-etch libgcrypt Ciphers: Absolute Time by Data Length 10 1 1 1 0.1 0.1 0.1 0.01 0.01 0.01 0.001 Seconds Seconds 0.001 Seconds 0.001 0.0001 0.0001 0.0001 1e-05 1e-05 1e-05 1e-06 10 100 1000 10000 100000 1000000 10 100 1000 10000 100000 1000000 10 100 1000 10000 100000 1000000 Data Length in Bytes Data Length in Bytes Data Length in Bytes Rijndael Twofish CAST5 Rijndael Twofish CAST5 Rijndael Twofish CAST5 Serpent Blowfish 3DES Serpent Blowfish 3DES Serpent Blowfish 3DES cel-2660-debian-etch libgcrypt Ciphers: Absolute Time by Data Length p4-3200-debian-etch libgcrypt Ciphers: Absolute Time by Data Length p4-3200-gentoo libgcrypt Ciphers: Absolute Time by Data Length 1 1 1 0.1 0.1 0.1 0.01 0.01 0.01 0.001 0.001 0.001 Seconds Seconds Seconds 0.0001 0.0001 0.0001 1e-05 1e-05 1e-05 1e-06 1e-06 1e-06 10 100 1000 10000 100000 1000000 10 100 1000 10000 100000 1000000 10 100 1000 10000 100000 1000000 Data Length in Bytes Data Length in Bytes Data Length in Bytes Rijndael Twofish CAST5 Rijndael Twofish CAST5 Rijndael Twofish CAST5 Serpent Blowfish 3DES Serpent Blowfish 3DES Serpent Blowfish 3DES p2-300-debian-etch libgcrypt Ciphers: Speed by Data Length p3-1000-debian-etch libgcrypt Ciphers: Speed by Data Length ath-2000-debian-etch libgcrypt Ciphers: Speed by Data Length 2.5 8 14 7 12 2 6 10 5 1.5 8 4 6 1 3 Megabyte / Second Megabyte / Second Megabyte / Second 4 2 0.5 1 2 0 0 0 10 100 1000 10000 100000
    [Show full text]
  • Block Ciphers
    ¡ ¢ £ ¤ ¥ ¦ § ¢ ¨ © ¤ ¢ © ¨ ¢ ¨ ¡ ¦ ¦ ¨ ¡ £ £ © © ¡ ¥ ¦ ¦ ¤ 4 BLOCK CIPHERS During the Cold War, the US and Soviets developed their own ciphers. The US government created the Data Encryption Standard (DES), which was adopted as a federal standard from 1979 to 2005, while the KGB developed GOST 28147-89, an algorithm kept secret until 1990 and still used today. In 2000, the US-based National Institute of Standards and Technology (NIST) selected the succes- sor to DES, called the Advanced Encryption Standard (AES), an algorithm developed in Belgium and now found in most electronic devices. AES, DES, and GOST 28147-89 have something in common: they’re all block ciphers , a type of cipher that combines a core algorithm working on blocks of data with a mode of operation, or a technique to process sequences of data blocks. ¡ ¢ £ ¤ ¥ ¦ § ¢ ¨ © ¤ ¢ © ¨ ¢ ¨ ¡ ¦ ¦ ¨ ¡ £ £ © © ¡ ¥ ¦ ¦ ¤ This chapter reviews the core algorithms that underlie block ciphers, discusses their modes of operation, and explains how they all work together. It also discusses how AES works and concludes with coverage of a classic attack tool from the 1970s, the meet-in-the-middle attack, and a favorite attack technique of the 2000s—padding oracles. What Is a Block Cipher? A block cipher consists of an encryption algorithm and a decryption algorithm: x The encryption algorithm ( E) takes a key, K, and a plaintext block, P, and produces a ciphertext block, C. We write an encryption operation as C = E(K, P). x The decryption algorithm ( D) is the inverse of the encryption algorithm and decrypts a message to the original plaintext, P. This operation is written as P = D(K, C).
    [Show full text]
  • Block Ciphers
    BLOCK CIPHERS 1 / 1 Permutations and Inverses A function f : {0, 1}ℓ → {0, 1}ℓ is a permutation if there is an inverse function f −1 : {0, 1}ℓ → {0, 1}ℓ satisfying ∀x ∈ {0, 1}ℓ : f −1(f (x)) = x This means f must be one-to-one and onto, meaning for every y ∈ {0, 1}ℓ there is a unique x ∈ {0, 1}ℓ such that f (x)= y. 2 / 1 Permutations and Inverses x 00 01 10 11 x 00 01 10 11 f (x) 01 11 00 10 f (x) 01 11 11 10 A permutation Not a permutation 3 / 1 Permutations and Inverses x 00 01 10 11 x 00 01 10 11 f (x) 01 11 00 10 f −1(x) 10 00 11 01 A permutation Its inverse 4 / 1 Block Ciphers Let E : {0, 1}k × {0, 1}ℓ → {0, 1}ℓ be a function taking a key K and input x to return output E(K, x). For ℓ ℓ each key K we let EK : {0, 1} → {0, 1} be the function defined by EK (x)= E(K, x) . We say that E is a block cipher if ℓ ℓ • EK : {0, 1} → {0, 1} is a permutation for every K, meaning has −1 an inverse EK , • E, E −1 are efficiently computable, −1 −1 where E (K, x)= EK (x). 5 / 1 Example The table entry corresponding to the key in row K and input in column x is EK (x). 00 01 10 11 00 00 01 10 11 01 01 00 11 10 10 10 11 00 01 11 11 10 01 00 In this case, the inverse cipher E −1 is given by the same table: the table entry corresponding to the key in row K and output in column y is −1 EK (y).
    [Show full text]