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INSTITUTO POLITÉCNICO NACIONAL INSTITUTO POLITÉCNICO NACIONAL

INSTITUTO POLITÉCNICO NACIONAL - PowerPoint Presentation

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INSTITUTO POLITÉCNICO NACIONAL - PPT Presentation

INSTITUTO POLITÉCNICO NACIONAL ESCUELA SUPERIOR DE CÓMPUTO   Cryptography M en C Nidia Asunción Cortez Duarte Cryptography NCD 2 Maestría en Ciencias Criptografía CINVESTAVIPN Ingeniería Sistemas Computacionales ID: 771727

ncd cryptography security information cryptography ncd information security key alice message classical encryption system encrypt john alphabet eva techniques

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INSTITUTO POLITÉCNICO NACIONAL ESCUELA SUPERIOR DE CÓMPUTO   Cryptography M. en C. Nidia Asunción Cortez Duarte

Cryptography -NCD 2 Maestría en Ciencias (Criptografía) CINVESTAV-IPN Ingeniería Sistemas Computacionales ESCOM-IPN (10ma generación) nidiacortez3@gmail.com www.comunidad.escom.ipn.mx/ncortez/ Departamento de Ingeniería en Sistemas Computacionales

Name Why did you choose this optative class? What do you know about cryptography?What’s the difference between cryptography and security information?Do you like program in HW or SW? Why? Cryptography -NCD 3

Cryptography -NCD 4 2015-2016/02 Group 3CM3Monday, Thursday 7:00 - 8:30Friday 8:30 – 10:00Laboratory LS3 (tolerance of 10 min)

AIM OF THE LEARNING UNIT: The student designs primitives and cryptographic applications using existant algorithms, techniques and existant tools.Cryptography -NCD5

Cryptography -NCD 6 Alice Bob

Cryptography -NCD 7 Alice Bob Candy

Cryptography -NCD 8 Security Shell Model

CONTENTS: U1: Cryptography Fundamentals . Definition and importance of cryptographyCryptographic services.Cryptographic system characteristics AttacksU2: Symmetric Cryptography. Symmetric cryptography characteristics  Perfect secrecyClassical cryptosystemsModern cryptography algorithmsModes of operationCryptography -NCD9

CONTENTS: U3: Public key Cryptography. Public key cryptography characteristics. Integers modulo n.Number theoryPublic key algorithmsU4: Digital Signatures. Hash functionsMessage authentication codes: MACDigital signatures.Cryptography -NCD10

REFERENCES Trappe, W. Washington, L. (2006). Introduction to Cryptography with Coding Theory (2ª Ed.). United States of America: Ed. Prentice Hall. ISBN-13: 978-0130618146.  Stallings, W. (2010). Cryptography and network security (5ª Ed.). United States of America: Ed. Prentice Hall. ISBN-13: 97800136097044.  Stinson, D. R. (2005). Cryptography: theory and practice (3ª Ed.). United States of America: Ed. Chapman&Hall/CRC. ISBN-13: 978-1584885085. Konheim, A. G. (2007). Computer Security and cryptography. United States of America: Ed. John Wiley & Sons. ISBN-13: 978-0471947837. Paar, C. Pelzl, J. Preneel B. (2009). Understanding Cryptography: A textbook for students and practitioners. United States of America: Ed. Springer Verlag. ISBN-13: 978-3642041006. Cryptography -NCD 11

LEARNING EVALUATION   Assessment Portfolio of Evidences: 1 2 3 Exercise-solving (class or hw) 30% 20% Laboratory Practices 20% 30% Learning Evidence 40% 40% 30% Quiz(s) 10% 10% Project 10% 70% Cryptography -NCD12

HW1 Read the story "The Gold Bug" In teams of 5 next Monday expose the story in English! http://www.comunidad.escom.ipn.mx/ncortez/Cryptography -NCD13

Class Cryptography -NCD 14

Since humans began sending each other secretmessages, they have been writing in code.Those messages wereMilitary plansSensitive blueprintsLove lettersEncrypting the communication can protect it from prying eyes.Cryptography -NCD 15

For thousands of years we have been inventing codes, and when those were broken we set about inventing better codes. The search for the unbreakable code continues ! Cryptography -NCD 16

Since a dictionary Kriptos = hide and graphos = write, the art to write in an enigmatic mode. .Cryptography -NCD17Cryptography

Cryptography -NCD 18 Cryptography Classical Modern TranspositionSubstitutionSymmetricAsymmetricalBlock Flows

Exersice Encrypt your first name with all the classic ciphers we will seeCipher n i d i a key Caesars QLGLD Shift-3 … … …Cryptography -NCD19

Exercise Suppose someone uses the Shift-19 cipher and sends the message LHXTLR to you, find the original message.Cryptography -NCD20

Let C1=3p+2C2= 2p+5Encrypt “ cryptography class” Cryptography -NCD21

Let C1=3p+2C2= 2p+5Encrypt “ cryptography class” Cryptography -NCD22

Let Encryption function C=7p+5 Find the decryption function C= LFICHLFIJTBIJLH Find the plaintext Cryptography -NCD 23

Cryptography -NCD 24 Julius Caesar 100 BC RomanShift CipherEgyptian writing systemhieroglyphRosetta StoneAncient Egyptian hieroglyps Demotic Ancient Greek

Cryptography -NCD 25 Slaves Shift-cipher Pig-pen Enigma Machine

Vigenere Encrypt p=cryptography class using the key=secretCryptography -NCD26

“ The study of mathematical techniques related to the aspects of information security, such as confidentiality, integrity and availability of the data, authentication of entity and origin, it doesn’t includes only the media to provide information security, but to a set of techniques.” Menezes & VanstoneCryptography -NCD27CryptographyHandbook of Applied Cryptography

Text Message which will be transmited in a safe way. Cipher Message that results after an encryption of the text. Key Is the information which allows to encrypt and decrypt the message.Cryptography -NCD28Cryptography

Cryptography -NCD 29 Cryptology Discipline which studies how to achieve secure communications over ways which aren’t besides it resolves another issues. (Disciplina que estudia cómo lograr comunicaciones seguras a través de formas que no son)Cryptography : the art to write in an enigmatic mode Cryptoanalisys Discipline which studies how to break cryptographic schemas.

Cryptography -NCD 30 In its clasification in science, cryptography comes from a branch of the mathematic, which was initiated by the mathematic Claude Elwood Shannon in 1948, denominated “Theory of the Information”. This branch of the science which is divided in: “Code Theory” and “Cryptology”. As the same way Cryptology is divided in Cryptanalisys and Cryptography, as it is shown in the next figure: Mathematics Theory of the InformationCode TheoryCryptologyCryptographyCryptoanalisys

Cryptography -NCD 31 Historically Cryptography can be clasified in two: Classical Cryptography it’s the one which was used before the actual age until half XX Century. It also can be understood as non computarized cryptography or non digitized.The used methods were varied, some very simple and other very complex to cryptanalize for the age.It can be said that the modern Cryptography was initiated after 3 facts: The first was the publication of the “Theory of Information” by Shannon.The second, the appearance in 1974 of the standard of the encryption system DES (Data Encryption Standard) and finally with the appearance of the study in 1976 made by Whitfield Diffle and Martin Hellman about the application of mathematic functions in a single way to a decrypt model named public key encrypt.Both classical and modern cryptography are classified in accordance to the techniques or methods which are used to encrypt messages. Clasification

Cryptography -NCD 32 Cryptography Classical Modern TranspositionSustitutionSymmetricAsymmetricalBlock Flows

Cryptography -NCD 33 As it was mentioned, classical cryptography is very old. The cryptographical techniques were very clever and were used to send secret messages between people who had the power or in the war age to send instructions. Unlike the modern cryptography, the algorythm of the cryptographic system was kept in secret.Classical Cryptography also includes the construction of machines, which through mechanisms, commonly gear and rotors, they transform a clear message to a encrypted message, like the Enigma machine used in the World War II.Classical Cryptography

Cryptography -NCD 34 Historical overview

Cryptography -NCD 35

Cryptography -NCD 36 Classical Encrypt

Cryptography -NCD 37 Babington’s mono-alphabetical encryption Used by Maria I, queen of the Scots [1542 AD]

The encryption alphabet consists in a rearrangement of the original text’s alphabet. Like that each letter of the original alphabet is always replaced for the same letter of the encryption alphabet 38 Sustitution Encrypt Cryptography-NCD Cryptography -NCD … How many different keys are in our alphabet ?

Cryptography -NCD 39 53++!305))6*;4826)4+.)4+);806*;48!8`60))85;]8*:+*8!83(88)5*!; 46(;88*96*?;8)*+(;485);5*!2:*+(;4956*2(5*-4)8`8*; 4069285);)6 !8)4++;1(+9;48081;8:8+1;48!85;4)485!528806*81(+9;48;(88;4(+?3 4;48)4+;161;:188;+?;'A good glass in the bishop's hostel in the devil's seat twenty-onedegrees and thirteen minutes northeast and by north main branchseventh limb east side shoot from the left eye of the death's-heada bee line from the tree through the shot fifty feet out.'

Class 3 Cryptography -NCD 40

Cryptography is a very useful tool when we want Computer Security confidentiality and integritycan be guaranteed, but we must know how touse it, to achieve that it’s important to haveclear the basic concepts of the moderncryptographyc systems. 41Cryptography -NCD Introduction

The need of Information Security in an enterprise has changed in the last decades, before the use of the computers, Information Security was provided by physical media, for example the use of safes and administrative measures, like document clasification procedures. With the computer, and even more with the arrival of the Internet, it has been essential the use of automatized tools for the protection of files and information stored in the computers, some of this tools are firewalls, IDS (Intrution Detection System) and cryptographyc systems. Cryptography -NCD 42

Cryptography -NCD 43 Attacks

Cryptography -NCD 44 Alice John

Eva’s objectives 1.Read the original message. 2.Get Alice’s secret key. 3.Modify the original message. 4 .Usurp Alice’s identity.Kerckhkoff’s PrincipleIt parts from the premise that the foe knows the used cryptographic algorithm. So, the system’s security must be based on:• The algorithm quality (strenght).• The key size (bit size of the key).Cryptography -NCD45

Cryptography -NCD 46 Alice John Eva

Cryptography -NCD 47 Alice John Eva Interruption

Cryptography -NCD 48 Alice John Eva InterruptionInterception

Cryptography -NCD 49 Alice John Eva InterruptionInterceptionModification

Cryptography -NCD 50 Alice John Eva InterruptionInterceptionModificationFabrication

Cryptography -NCD 51 “Yes, I do.” Alice “No, I don’t.”Alice

Cryptography -NCD 52 Definitions Security According to the Real Spanish Academy means:Attribute of secure.Said of a mechanism which assures a correct behavior, forseeing failures, frustration or violent. Information Security. We can talk about it like the set of rules, plans and actions which allow the assurance of the information keeping the properties of confidentiality, integity and availability. Confidentiality means that the information can be read only by those who are authorized. Integrity means that the information can only be created and modified for those who are authorized, and that the information keeps it hole structure and completeness. Avilability means that the information must be accessible for consult or modification in the time it’s needed only for those who are authorized. Computer Security. Set of policies and mechanisms which allows us to guarantee the confidentiality, integrity and availability of the system resources (Understand system resources as the processing memory, storage in a physical device, processing time, band width and the information stored in the system).

Cryptography -NCD 53 Integridad Autenticación No repudio

HOMEWORK Consider the spanish alphabet, m=3 P=“amigoconductor” Key=“peligroso” find CFind www.comunidad.escom.ipn.mx/ncortez/ Download RFC DES   Cryptography -NCD 54

Cryptography -NCD 55