Dr. Jinyuan (Stella) Sun Dept. of Electrical Engineering and Computer Science University of Tennessee Fall 2010


 Tyrone Rogers
 3 years ago
 Views:
Transcription
1 CS 494/594 Computer and Network Security Dr. Jinyuan (Stella) Sun Dept. of Electrical Engineering and Computer Science University of Tennessee Fall
2 Introduction to Cryptography What is cryptography? Types of cryptography Attacks on cryptosystem Early ciphers SKC, PKC, Hash Security notions 2
3 What Is Cryptography? Cryptography is the art of secret writing Traditional use: encryption Cryptographic systems: algorithm+secret Cryptology: cryptography+cryptanalysis 3
4 Types of Cryptography Operations used to transform plaintext to ciphertext:  Substitution: each element in plaintext is mapped into another element  Transposition: elements in plaintext are rearranged Number of keys used:  Singlekey: secretkey cryptography  Twokey: publickey cryptography  Zerokey: hash functions The way plaintext is processed:  Block cipher: input & output in blocks  Stream cipher: input & output in bits 4
5 Conventional Cryptography: Symmetric Encryption Plaintext: original message Encryption algorithm: substitutions/transpositions Secret key: independent of plaintext and algorithm Ciphertext: depends on plaintext and key, appears random Decryption algorithm: reverse of encryption 5
6 Attacking Cryptosystems Cryptanalysis: attempts to deduce the plaintext and/or the key being used, with knowledge of the nature of the algorithm + general characteristics of plaintext + some sample plaintextciphertext pairs Bruteforce attack: attacker tries every possible key on a piece of ciphertext until an intelligible translation into plaintext is obtained. On average, half of all possible keys must be tried to achieve success. 6
7 Types of Cryptanalytic Attacks 7
8 Bruteforce Attacks Average Time Required for Exhaustive Key Search 8
9 Early Ciphers: Substitution Substitution: letters of plaintext are replaced by other letters or by numbers or symbols, involves replacing plaintext bit patterns with ciphertext bit patterns Caesar cipher Captain Midnight Secret Decoder Rings Monoalphabetic cipher Hill cipher Polyalphabetic cipher (Vigenere) Onetime pad 9
10 Caesar Cipher Replacing each letter of the alphabet with the letter three places further down the alphabet, e.g., Captain Midnight Secret Decoder Ring (slightly enhanced): If a numerical value is assigned to each letter, for each plaintext letter p, the ciphertext letter C=E(k, p)=(p+k) mod 26 where k takes on the value in [1,25]: Subject to bruteforce attack: simply try all 25 possible k 10
11 Monoalphabetic Cipher The "cipher" line can be any permutation of the 26 alphabetic characters, 26! or around 4x10 26 possible keys: Is it secure enough to resist cryptanalysis? Consider: By exploiting the regularities of the language and counting letter frequencies: The following can be recovered: 11
12 Hill Cipher Takes m successive plaintext letters and substitutes for them m ciphertext letters The substitution is determined by m linear equations in which each character is assigned a numerical value (a = 0, b = 1... z = 25) For example: m = 3 for plaintext paymoremoney and encryption key we have ciphertext: LNSHDLEWMTRW 12
13 Polyalphabetic Cipher Use different monoalphabetic substitutions as one proceeds through the plaintext message Vigenere cipher: best known polyalphabetic cipher. The set of related monoalphabetic substitution rules consists of the 26 Caesar ciphers, with shifts of 0 through 25. For keyword deceptive and plaintext we are discovered save yourself, the encryption works as: Vulnerable to cryptanalysis: the key and plaintext share the same language regularities and frequency distribution of letters. Solutions? 13
14 Onetime Pad Use a random key that is as long as the message so that the key need not be repeated The key is used to encrypt and decrypt a single message, and then is discarded Perfectly secure: unbreakable because it produces random output (from the random key) that bears no statistical relationship to the plaintext Drawbacks: large quantities of random keys needed, key distribution and protection (both sender and receiver) 14
15 Early Ciphers: Transposition Different from substituting a ciphertext symbol for a plaintext symbol Transposition cipher: performs some sort of permutation/rearrangement on plaintext letters Cryptanalysis is straightforward: a transposition cipher has the same letter frequency as plaintext Can be made more secure by performing more than one stage of transposition (result is not easily reconstructed) 15
16 Rail Fence Cipher Simplest transposition cipher Plaintext is written down as a sequence of diagonals and then read off as a sequence of rows Plaintext: Ciphertext: Trivial to attack 16
17 Double Transposition A more complex scheme: permute the order of the columns with a key Double transposition: more than one permutation, number the above plaintext letters 128 and after the first permutation we have After the 2 nd permutation? 17
18 Secret Key Cryptography (SKC) Aka: conventional cryptography, symmetric cryptography Use a single key Ciphertext about the same length as plaintext Examples: Captain Midnight code, monoalphabetic cipher, DES, AES, RC4 plaintext encryption shared secret key ciphertext ciphertext decryption plaintext 18
19 SKC Applications Transmitting over an insecure channel Secure storage on insecure media Authentication: Integrity check: message authentication code (MAC), aka, message integrity check (MIC) 19
20 Public Key Cryptography (PKC) Aka: asymmetric cryptography, invented in 1970s Use two keys: a public key known to everyone, a private key kept secret to the owner Encryption/decryption: encryption can be done by everyone using the recipient s public key, decryption can be done only by the recipient with his/her private key encryption plaintext ciphertext pub B ( puba, pri A) ( pubb, prib) pri B ciphertext decryption plaintext 20
21 PKC Applications Everything that SKC does can be done by PKC Transmitting over an insecure channel Secure storage over insecure media Authentication Key exchange: establish a shared session key with PKC 21
22 PKC Applications (Cont d) Digital signature: nonrepudiation plaintext sign Signed message pri A ( puba, pri A) ( pubb, prib) pub A Signed message verify True or false 22
23 Hash Functions Aka: message digests, oneway transformations Take a message m of arbitrary length (transformed into a string of bits) and computes from it a fixedlength (short) number h(m) Properties:  easytocompute: for any message m, it is relatively easy to compute h(m)  nonreversible: given h(m), there is no way to find an m that hashes to h(m) except trying all possibilities of m  computationally infeasible to find m and m such that h(m)=h(m ) and m!=m 23
24 Applications of Hash Functions Password hashing Message integrity: keyed hash File fingerprint Downline load security Digital signature efficiency 24
25 Security Notions Unconditionally secure: ciphertext generated by the scheme does not contain enough information to determine uniquely the corresponding plaintext, no matter how much ciphertext is available. Perfectly secure, unlimited power of adversary Provably secure: under the assumption of wellknown hard mathematical problem, e.g., factoring large numbers, discrete logarithm problem Computationally secure: if cost of breaking the cipher exceeds the value of the encrypted information, or time required to break the cipher exceeds the useful lifetime of the information, practical security 25
26 Cryptography vs. Steganography Cryptography conceals the context of message Steganography conceals the existence of message, useful when the fact of secret communication should be concealed  an arrangement of words/letters of the overall message spells out the hidden message  character marking: selected letters overwritten in pencil, not visible unless the paper is held at an angle to bright light  invisible ink: substances used for writing but leave no visible trace until heat or some chemical is applied to the paper  pin punctures: small pin punctures on selected letters are not visible unless the paper is held up in front of a light Drawbacks of steganography: high overhead to hide a relatively few bits of information, becomes worthless once the system is discovered (can make insertion depend on key) 26
27 Reading Assignments [Kaufman] Chapter 2 27
uses same key for encryption, decryption classical, conventional, singlekey encryption
CEN 448 Security and Internet Protocols Chapter 2 Classical Encryption Techniques Dr. Mostafa Hassan Dahshan Computer Engineering Department College of Computer and Information Sciences King Saud University
More informationCryptography & Network Security
Cryptography & Network Security Lecture 1: Introduction & Overview 2002. 3. 27 chlim@sejong.ac.kr Common Terms(1) Cryptography: The study of mathematical techniques related to aspects of information security
More informationCryptography and Network Security
Cryptography and Network Security XiangYang Li Introduction The art of war teaches us not on the likelihood of the enemy s not coming, but on our own readiness to receive him; not on the chance of his
More informationAPNIC elearning: Cryptography Basics. Contact: esec02_v1.0
APNIC elearning: Cryptography Basics Contact: training@apnic.net esec02_v1.0 Overview Cryptography Cryptographic Algorithms Encryption SymmetricKey Algorithm Block and Stream Cipher Asymmetric Key Algorithm
More informationNetwork Security. HIT Shimrit TzurDavid
Network Security HIT Shimrit TzurDavid 1 Goals: 2 Network Security Understand principles of network security: cryptography and its many uses beyond confidentiality authentication message integrity key
More informationChapter 11 Security+ Guide to Network Security Fundamentals, Third Edition Basic Cryptography
Chapter 11 Security+ Guide to Network Security Fundamentals, Third Edition Basic Cryptography What Is Steganography? Steganography Process of hiding the existence of the data within another file Example:
More informationNetwork Security. Security Attacks. Normal flow: Interruption: 孫 宏 民 hmsun@cs.nthu.edu.tw Phone: 035742968 國 立 清 華 大 學 資 訊 工 程 系 資 訊 安 全 實 驗 室
Network Security 孫 宏 民 hmsun@cs.nthu.edu.tw Phone: 035742968 國 立 清 華 大 學 資 訊 工 程 系 資 訊 安 全 實 驗 室 Security Attacks Normal flow: sender receiver Interruption: Information source Information destination
More information9/17/2015. Cryptography Basics. Outline. Encryption/Decryption. Cryptanalysis. Caesar Cipher. MonoAlphabetic Ciphers
Cryptography Basics IT443 Network Security Administration Instructor: Bo Sheng Outline Basic concepts in cryptography system Secret cryptography Public cryptography Hash functions 1 2 Encryption/Decryption
More informationCryptography: Motivation. Data Structures and Algorithms Cryptography. Secret Writing Methods. Many areas have sensitive information, e.g.
Cryptography: Motivation Many areas have sensitive information, e.g. Data Structures and Algorithms Cryptography Goodrich & Tamassia Sections 3.1.3 & 3.1.4 Introduction Simple Methods Asymmetric methods:
More informationNetwork Security. Computer Networking Lecture 08. March 19, 2012. HKU SPACE Community College. HKU SPACE CC CN Lecture 08 1/23
Network Security Computer Networking Lecture 08 HKU SPACE Community College March 19, 2012 HKU SPACE CC CN Lecture 08 1/23 Outline Introduction Cryptography Algorithms Secret Key Algorithm Message Digest
More informationSecret Writing. Introduction to Cryptography. Encryption. Decryption. Kerckhoffs s ( ) Principle. Security of Cryptographic System
Introduction to Cryptography ECEN 1200, Telecommunications 1 Secret Writing Cryptography is the science and study of secret writing. More specifically, cryptography is concerned with techniques for enciphering
More informationCryptography and Network Security Chapter 2
Cryptography and Network Security Chapter 2 Fifth Edition by William Stallings Lecture slides by Lawrie Brown (with edits by RHB) Chapter 2 Classical Encryption Techniques "I am fairly familiar with all
More informationApplied Cryptology. Ed Crowley
Applied Cryptology Ed Crowley 1 Basics Topics Basic Services and Operations Symmetric Cryptography Encryption and Symmetric Algorithms Asymmetric Cryptography Authentication, Nonrepudiation, and Asymmetric
More informationCryptography and Network Security
Cryptography and Network Security Spring 2012 http://users.abo.fi/ipetre/crypto/ Lecture 1: Introduction Ion Petre Department of IT, Åbo Akademi University January 10, 2012 1 Motto Unfortunately, the technical
More informationNetwork Security CS 5490/6490 Fall 2015 Lecture Notes 8/26/2015
Network Security CS 5490/6490 Fall 2015 Lecture Notes 8/26/2015 Chapter 2: Introduction to Cryptography What is cryptography? It is a process/art of mangling information in such a way so as to make it
More information159.334 Computer Networks. Network Security 1. Professor Richard Harris School of Engineering and Advanced Technology
Network Security 1 Professor Richard Harris School of Engineering and Advanced Technology Presentation Outline Overview of Identification and Authentication The importance of identification and Authentication
More informationOverview of Cryptographic Tools for Data Security. Murat Kantarcioglu
UT DALLAS Erik Jonsson School of Engineering & Computer Science Overview of Cryptographic Tools for Data Security Murat Kantarcioglu Pag. 1 Purdue University Cryptographic Primitives We will discuss the
More informationIntroduction to Cryptography
Introduction to Cryptography Part 2: publickey cryptography JeanSébastien Coron January 2007 Publickey cryptography Invented by Diffie and Hellman in 1976. Revolutionized the field. Each user now has
More informationCryptology introduction
Cryptology introduction Martin Stanek Department of Computer Science Comenius University stanek@dcs.fmph.uniba.sk Cryptology 1 (2015/16) Content Introduction security requirements Encryption simple examples,
More informationIT Networks & Security CERT Luncheon Series: Cryptography
IT Networks & Security CERT Luncheon Series: Cryptography Presented by Addam Schroll, IT Security & Privacy Analyst 1 Outline History Terms & Definitions Symmetric and Asymmetric Algorithms Hashing PKI
More informationSandeep Mahapatra Department of Computer Science and Engineering PEC, University of Technology s.mahapatra15101987@gmail.com
Computing For Nation Development, March 10 11, 2011 Bharati Vidyapeeth s Institute of Computer Applications and Management, New Delhi A Comparative Evaluation of Various Encryptions Techniques Committing
More informationCryptography and Network Security Department of Computer Science and Engineering Indian Institute of Technology Kharagpur
Cryptography and Network Security Department of Computer Science and Engineering Indian Institute of Technology Kharagpur Module No. # 01 Lecture No. # 05 Classic Cryptosystems (Refer Slide Time: 00:42)
More informationNetwork Security: Cryptography CS/SS G513 S.K. Sahay
Network Security: Cryptography CS/SS G513 S.K. Sahay BITSPilani, K.K. Birla Goa Campus, Goa S.K. Sahay Network Security: Cryptography 1 Introduction Network security: measure to protect data/information
More informationCIS 6930 Emerging Topics in Network Security. Topic 2. Network Security Primitives
CIS 6930 Emerging Topics in Network Security Topic 2. Network Security Primitives 1 Outline Absolute basics Encryption/Decryption; Digital signatures; DH key exchange; Hash functions; Application of hash
More informationCRYPTOGRAPHY IN NETWORK SECURITY
ELE548 Research Essays CRYPTOGRAPHY IN NETWORK SECURITY AUTHOR: SHENGLI LI INSTRUCTOR: DR. JIENCHUNG LO Date: March 5, 1999 Computer network brings lots of great benefits and convenience to us. We can
More informationApplication Layer (1)
Application Layer (1) Functionality: providing applications (email, Web service, USENET, ftp etc) providing support protocols to allow the real applications to function properly (e.g. HTTP for Web appl.)
More informationSecurity usually depends on the secrecy of the key, not the secrecy of the algorithm (i.e., the open design model!)
1 A cryptosystem has (at least) five ingredients: 1. 2. 3. 4. 5. Plaintext Secret Key Ciphertext Encryption algorithm Decryption algorithm Security usually depends on the secrecy of the key, not the secrecy
More informationChapter 10. Network Security
Chapter 10 Network Security 10.1. Chapter 10: Outline 10.1 INTRODUCTION 10.2 CONFIDENTIALITY 10.3 OTHER ASPECTS OF SECURITY 10.4 INTERNET SECURITY 10.5 FIREWALLS 10.2 Chapter 10: Objective We introduce
More informationLecture 9: Application of Cryptography
Lecture topics Cryptography basics Using SSL to secure communication links in J2EE programs Programmatic use of cryptography in Java Cryptography basics Encryption Transformation of data into a form that
More informationToday ENCRYPTION. Cryptography example. Basic principles of cryptography
Today ENCRYPTION The last class described a number of problems in ensuring your security and privacy when using a computer online. This lecture discusses one of the main technological solutions. The use
More informationCryptography and Cryptanalysis
Cryptography and Cryptanalysis Feryâl Alayont University of Arizona December 9, 2003 1 Cryptography: derived from the Greek words kryptos, meaning hidden, and graphos, meaning writing. Cryptography is
More informationCIS433/533  Computer and Network Security Cryptography
CIS433/533  Computer and Network Security Cryptography Professor Kevin Butler Winter 2011 Computer and Information Science A historical moment Mary Queen of Scots is being held by Queen Elizabeth and
More informationTable of Contents. Bibliografische Informationen http://dnb.info/996514864. digitalisiert durch
1 Introduction to Cryptography and Data Security 1 1.1 Overview of Cryptology (and This Book) 2 1.2 Symmetric Cryptography 4 1.2.1 Basics 4 1.2.2 Simple Symmetric Encryption: The Substitution Cipher...
More informationData Encryption A B C D E F G H I J K L M N O P Q R S T U V W X Y Z. we would encrypt the string IDESOFMARCH as follows:
Data Encryption Encryption refers to the coding of information in order to keep it secret. Encryption is accomplished by transforming the string of characters comprising the information to produce a new
More informationChapter 23. Database Security. Security Issues. Database Security
Chapter 23 Database Security Security Issues Legal and ethical issues Policy issues Systemrelated issues The need to identify multiple security levels 2 Database Security A DBMS typically includes a database
More informationBlock encryption. CS4920: Lecture 7 Secret key cryptography. Determining the plaintext ciphertext mapping. CS4920Lecture 7 4/1/2015
CS4920: Lecture 7 Secret key cryptography Reading Chapter 3 (pp. 5975, 9293) Today s Outcomes Discuss block and key length issues related to secret key cryptography Define several terms related to secret
More informationCommon Pitfalls in Cryptography for Software Developers. OWASP AppSec Israel July 2006. The OWASP Foundation http://www.owasp.org/
Common Pitfalls in Cryptography for Software Developers OWASP AppSec Israel July 2006 Shay Zalalichin, CISSP AppSec Division Manager, Comsec Consulting shayz@comsecglobal.com Copyright 2006  The OWASP
More informationSymmetric Key cryptosystem
SFWR C03: Computer Networks and Computer Security Mar 811 200 Lecturer: Kartik Krishnan Lectures 222 Symmetric Key cryptosystem Symmetric encryption, also referred to as conventional encryption or single
More information7! Cryptographic Techniques! A Brief Introduction
7! Cryptographic Techniques! A Brief Introduction 7.1! Introduction to Cryptography! 7.2! Symmetric Encryption! 7.3! Asymmetric (PublicKey) Encryption! 7.4! Digital Signatures! 7.5! Public Key Infrastructures
More informationTutorial 2. May 11, 2015
Tutorial 2 May 11, 2015 I. Basic Notions Review Questions Chapter 5 & 11 Multiplechoice Example Chapter 5 Which is the first step in securing an operating system? a. implement patch management b. configure
More informationSECURITY IMPROVMENTS TO THE DIFFIEHELLMAN SCHEMES
www.arpapress.com/volumes/vol8issue1/ijrras_8_1_10.pdf SECURITY IMPROVMENTS TO THE DIFFIEHELLMAN SCHEMES Malek Jakob Kakish Amman Arab University, Department of Computer Information Systems, P.O.Box 2234,
More informationCS 348: Computer Networks.  Security; 30 th  31 st Oct 2012. Instructor: Sridhar Iyer IIT Bombay
CS 348: Computer Networks  Security; 30 th  31 st Oct 2012 Instructor: Sridhar Iyer IIT Bombay Network security Security Plan (RFC 2196) Identify assets Determine threats Perform risk analysis Implement
More informationNetwork Security (2) CPSC 441 Department of Computer Science University of Calgary
Network Security (2) CPSC 441 Department of Computer Science University of Calgary 1 Friends and enemies: Alice, Bob, Trudy wellknown in network security world Bob, Alice (lovers!) want to communicate
More informationSAMPLE EXAM QUESTIONS MODULE EE5552 NETWORK SECURITY AND ENCRYPTION ECE, SCHOOL OF ENGINEERING AND DESIGN BRUNEL UNIVERSITY UXBRIDGE MIDDLESEX, UK
SAMPLE EXAM QUESTIONS MODULE EE5552 NETWORK SECURITY AND ENCRYPTION September 2010 (reviewed September 2014) ECE, SCHOOL OF ENGINEERING AND DESIGN BRUNEL UNIVERSITY UXBRIDGE MIDDLESEX, UK NETWORK SECURITY
More informationApplication Layer (1)
Application Layer (1) Functionality: providing applications (email, www, USENET etc) providing support protocols to allow the real applications to function properly security comprising a large number
More informationThe Elements of Cryptography
The Elements of Cryptography (March 30, 2016) Abdou Illia Spring 2016 Learning Objectives Discuss Cryptography Terminology Discuss Symmetric Key Encryption Discuss Asymmetric Key Encryption Distinguish
More informationIntroduction to Cryptography CS 355
Introduction to Cryptography CS 355 Lecture 2 Classical Cryptography: Shift Cipher and Substitution Cipher CS 355 Fall 2005/Lecture 2 1 Announcements Join class mailing list CS355_Fall2005@cs.purdue.edu
More informationSECURITY IN NETWORKS
SECURITY IN NETWORKS GOALS Understand principles of network security: Cryptography and its many uses beyond confidentiality Authentication Message integrity Security in practice: Security in application,
More informationEvaluation of the RC4 Algorithm for Data Encryption
Evaluation of the RC4 Algorithm for Data Encryption Allam Mousa (1) and Ahmad Hamad (2) (1) Electrical Engineering Department AnNajah University, Nablus, Palestine (2) Systems Engineer PalTel Company,
More informationLecture 9  Network Security TDTS412006 (ht1)
Lecture 9  Network Security TDTS412006 (ht1) Prof. Dr. Christoph Schuba Linköpings University/IDA Schuba@IDA.LiU.SE Reading: Office hours: [Hal05] 10.110.2.3; 10.2.510.7.1; 10.8.1 910am on Oct. 4+5,
More informationShift Cipher. Ahmet Burak Can Hacettepe University. Substitution Cipher. Enigma Machine. How perfect secrecy can be satisfied?
One Time Pad, Block Ciphers, Encryption Modes Ahmet Burak Can Hacettepe University abc@hacettepe.edu.tr Basic Ciphers Shift Cipher Bruteforce attack can easily break Substitution Cipher Frequency analysis
More informationFundamentals of Computer Security
Fundamentals of Computer Security Spring 2015 Radu Sion Intro Encryption Hash Functions A Message From Our Sponsors Fundamentals System/Network Security, crypto How do things work Why How to design secure
More informationIntroduction To Security and Privacy Einführung in die ITSicherheit I
Introduction To Security and Privacy Einführung in die ITSicherheit I Prof. Dr. rer. nat. Doğan Kesdoğan Institut für Wirtschaftsinformatik kesdogan@fb5.unisiegen.de http://www.unisiegen.de/fb5/itsec/
More informationCryptosystems. Bob wants to send a message M to Alice. Symmetric ciphers: Bob and Alice both share a secret key, K.
Cryptosystems Bob wants to send a message M to Alice. Symmetric ciphers: Bob and Alice both share a secret key, K. C= E(M, K), Bob sends C Alice receives C, M=D(C,K) Use the same key to decrypt. Public
More informationCSCE 465 Computer & Network Security
CSCE 465 Computer & Network Security Instructor: Dr. Guofei Gu http://courses.cse.tamu.edu/guofei/csce465/ Public Key Cryptogrophy 1 Roadmap Introduction RSA DiffieHellman Key Exchange Public key and
More informationMessage Authentication Codes
2 MAC Message Authentication Codes : and Cryptography Sirindhorn International Institute of Technology Thammasat University Prepared by Steven Gordon on 28 October 2013 css322y13s2l08, Steve/Courses/2013/s2/css322/lectures/mac.tex,
More informationCryptographic hash functions and MACs Solved Exercises for Cryptographic Hash Functions and MACs
Cryptographic hash functions and MACs Solved Exercises for Cryptographic Hash Functions and MACs Enes Pasalic University of Primorska Koper, 2014 Contents 1 Preface 3 2 Problems 4 2 1 Preface This is a
More informationCSCIE46: Applied Network Security. Class 1: Introduction Cryptography Primer 1/26/16 CSCIE46: APPLIED NETWORK SECURITY, SPRING 2016 1
CSCIE46: Applied Network Security Class 1: Introduction Cryptography Primer 1/26/16 CSCIE46: APPLIED NETWORK SECURITY, SPRING 2016 1 Welcome to CSCIE46 Classroom & Schedule 53 Church Street L01 Wednesdays,
More informationAC76/AT76 CRYPTOGRAPHY & NETWORK SECURITY DEC 2014
Q.2a. Define Virus. What are the four phases of Viruses? In addition, list out the types of Viruses. A virus is a piece of software that can infect other programs by modifying them; the modification includes
More informationLecture 5  Cryptography
CSE497b Introduction to Computer and Network Security  Spring 2007  Professors Jaeger Lecture 5  Cryptography CSE497b  Spring 2007 Introduction Computer and Network Security Professor Jaeger www.cse.psu.edu/~tjaeger/cse497bs07/
More informationChapter 23. Database Security. Security Issues. Database Security
Chapter 23 Database Security Security Issues Legal and ethical issues Policy issues Systemrelated issues The need to identify multiple security levels 2 Database Security A DBMS typically includes a database
More informationCS 758: Cryptography / Network Security
CS 758: Cryptography / Network Security offered in the Fall Semester, 2003, by Doug Stinson my office: DC 3122 my email address: dstinson@uwaterloo.ca my web page: http://cacr.math.uwaterloo.ca/~dstinson/index.html
More informationChap 2. Basic Encryption and Decryption
Chap 2. Basic Encryption and Decryption H. Lee Kwang Department of Electrical Engineering & Computer Science, KAIST Objectives Concepts of encryption Cryptanalysis: how encryption systems are broken 2.1
More informationCSE331: Introduction to Networks and Security. Lecture 20 Fall 2006
CSE331: Introduction to Networks and Security Lecture 20 Fall 2006 Announcements Homework 2 has been assigned: **NEW DUE DATE** It's now due on Friday, November 3rd. Midterm 2 is Friday, November 10th
More informationNetwork Security. Abusayeed Saifullah. CS 5600 Computer Networks. These slides are adapted from Kurose and Ross 81
Network Security Abusayeed Saifullah CS 5600 Computer Networks These slides are adapted from Kurose and Ross 81 Public Key Cryptography symmetric key crypto v requires sender, receiver know shared secret
More informationFAREY FRACTION BASED VECTOR PROCESSING FOR SECURE DATA TRANSMISSION
FAREY FRACTION BASED VECTOR PROCESSING FOR SECURE DATA TRANSMISSION INTRODUCTION GANESH ESWAR KUMAR. P Dr. M.G.R University, Maduravoyal, Chennai. Email: geswarkumar@gmail.com Every day, millions of people
More informationCryptography and Network Security
Cryptography and Network Security Spring 2012 http://users.abo.fi/ipetre/crypto/ Lecture 3: Block ciphers and DES Ion Petre Department of IT, Åbo Akademi University January 17, 2012 1 Data Encryption Standard
More informationAbout the Tutorial. Audience. Prerequisites. Disclaimer & Copyright. Cryptography
About the Tutorial This tutorial covers the basics of the science of cryptography. It explains how programmers and network professionals can use cryptography to maintain the privacy of computer data. Starting
More informationToday. Network Security. Crypto as Munitions. Crypto as Munitions. History of Cryptography
Network Security Symmetric Key Cryptography Today Substitution Ciphers Transposition Ciphers Cryptanalysis 1 2 Crypto as Munitions Does: protecting information kill enemies? failure to protect information
More informationNetwork Security Technology Network Management
COMPUTER NETWORKS Network Security Technology Network Management Source Encryption E(K,P) Decryption D(K,C) Destination The author of these slides is Dr. Mark Pullen of George Mason University. Permission
More informationStream Ciphers. Example of Stream Decryption. Example of Stream Encryption. Real Cipher Streams. Terminology. Introduction to Modern Cryptography
Introduction to Modern Cryptography Lecture 2 Symmetric Encryption: Stream & Block Ciphers Stream Ciphers Start with a secret key ( seed ) Generate a keying stream ith bit/byte of keying stream is a function
More informationPart I. Universität Klagenfurt  IWAS Multimedia Kommunikation (VK) M. Euchner; Mai 2001. Siemens AG 2001, ICN M NT
Part I Contents Part I Introduction to Information Security Definition of Crypto Cryptographic Objectives Security Threats and Attacks The process Security Security Services Cryptography Cryptography (code
More informationOutline. Computer Science 418. Digital Signatures: Observations. Digital Signatures: Definition. Definition 1 (Digital signature) Digital Signatures
Outline Computer Science 418 Digital Signatures Mike Jacobson Department of Computer Science University of Calgary Week 12 1 Digital Signatures 2 Signatures via Public Key Cryptosystems 3 Provable 4 Mike
More informationIntroduction to Computer Security
Introduction to Computer Security Hash Functions and Digital Signatures Pavel Laskov Wilhelm Schickard Institute for Computer Science Integrity objective in a wide sense Reliability Transmission errors
More informationCryptography and Network Security Prof. D. Mukhopadhyay Department of Computer Science and Engineering Indian Institute of Technology, Karagpur
Cryptography and Network Security Prof. D. Mukhopadhyay Department of Computer Science and Engineering Indian Institute of Technology, Karagpur Lecture No. #06 Cryptanalysis of Classical Ciphers (Refer
More informationAn Introduction to Cryptography and Digital Signatures
An Introduction to Cryptography and Digital Signatures Author: Ian Curry March 2001 Version 2.0 Copyright 20012003 Entrust. All rights reserved. Cryptography The concept of securing messages through
More informationCryptography & Digital Signatures
Cryptography & Digital Signatures CS 594 Special Topics/Kent Law School: Computer and Network Privacy and Security: Ethical, Legal, and Technical Consideration Prof. Sloan s Slides, 2007, 2008 Robert H.
More informationMessage Authentication
Message Authentication message authentication is concerned with: protecting the integrity of a message validating identity of originator nonrepudiation of origin (dispute resolution) will consider the
More informationLukasz Pater CMMS Administrator and Developer
Lukasz Pater CMMS Administrator and Developer EDMS 1373428 Agenda Introduction Why do we need asymmetric ciphers? Oneway functions RSA Cipher Message Integrity Examples Secure Socket Layer Single Sign
More informationCRYPTOGRAPHIC PRIMITIVES AN INTRODUCTION TO THE THEORY AND PRACTICE BEHIND MODERN CRYPTOGRAPHY
CRYPTOGRAPHIC PRIMITIVES AN INTRODUCTION TO THE THEORY AND PRACTICE BEHIND MODERN CRYPTOGRAPHY Robert Sosinski Founder & Engineering Fellow Known as "America's Cryptologic Wing", is the only Air Force
More informationEffective Secure Encryption Scheme [One Time Pad] Using Complement Approach Sharad Patil 1 Ajay Kumar 2
Effective Secure Encryption Scheme [One Time Pad] Using Complement Approach Sharad Patil 1 Ajay Kumar 2 Research Student, Bharti Vidyapeeth, Pune, India sd_patil057@rediffmail.com Modern College of Engineering,
More informationIntroduction. Digital Signature
Introduction Electronic transactions and activities taken place over Internet need to be protected against all kinds of interference, accidental or malicious. The general task of the information technology
More informationPublic Key (asymmetric) Cryptography
PublicKey Cryptography UNIVERSITA DEGLI STUDI DI PARMA Dipartimento di Ingegneria dell Informazione Public Key (asymmetric) Cryptography Luca Veltri (mail.to: luca.veltri@unipr.it) Course of Network Security,
More informationCryptography and Network Security Chapter 11. Fourth Edition by William Stallings
Cryptography and Network Security Chapter 11 Fourth Edition by William Stallings Chapter 11 Message Authentication and Hash Functions At cats' green on the Sunday he took the message from the inside of
More informationCryptographic process for Cyber Safeguard by using PGP
Cryptographic process for Cyber Safeguard by using PGP Bharatratna P. Gaikwad 1 Department of Computer Science and IT, Dr. Babasaheb Ambedkar Marathwada University Aurangabad, India 1 ABSTRACT: Data security
More informationCSE/EE 461 Lecture 23
CSE/EE 461 Lecture 23 Network Security David Wetherall djw@cs.washington.edu Last Time Naming Application Presentation How do we name hosts etc.? Session Transport Network Domain Name System (DNS) Data
More informationChapter 7: Network security
Chapter 7: Network security Foundations: what is security? cryptography authentication message integrity key distribution and certification Security in practice: application layer: secure email transport
More informationKy Vu DeVry University, Atlanta Georgia College of Arts & Science
Ky Vu DeVry University, Atlanta Georgia College of Arts & Science Table of Contents  Objective  Cryptography: An Overview  Symmetric Key  Asymmetric Key  Transparent Key: A Paradigm Shift  Security
More informationClient Server Registration Protocol
Client Server Registration Protocol The ClientServer protocol involves these following steps: 1. Login 2. Discovery phase User (Alice or Bob) has K s Server (S) has hash[pw A ].The passwords hashes are
More informationPUBLIC KEY ENCRYPTION
PUBLIC KEY ENCRYPTION http://www.tutorialspoint.com/cryptography/public_key_encryption.htm Copyright tutorialspoint.com Public Key Cryptography Unlike symmetric key cryptography, we do not find historical
More informationModes of Operation of Block Ciphers
Chapter 3 Modes of Operation of Block Ciphers A bitblock encryption function f: F n 2 Fn 2 is primarily defined on blocks of fixed length n To encrypt longer (or shorter) bit sequences the sender must
More informationThe Data Encryption Standard (DES)
The Data Encryption Standard (DES) As mentioned earlier there are two main types of cryptography in use today  symmetric or secret key cryptography and asymmetric or public key cryptography. Symmetric
More information6.857 Computer and Network Security Fall Term, 1997 Lecture 4 : 16 September 1997 Lecturer: Ron Rivest Scribe: Michelle Goldberg 1 Conditionally Secure Cryptography Conditionally (or computationally) secure
More informationPrinciples of Network Security
he Network Security Model Bob and lice want to communicate securely. rudy (the adversary) has access to the channel. lice channel data, control s Bob Kai Shen data secure sender secure receiver data rudy
More informationCryptography Exercises
Cryptography Exercises 1 Contents 1 source coding 3 2 Caesar Cipher 4 3 Ciphertextonly Attack 5 4 Classification of CryptosystemsNetwork Nodes 6 5 Properties of modulo Operation 10 6 Vernam Cipher 11
More informationRecommendation for Applications Using Approved Hash Algorithms
NIST Special Publication 800107 Recommendation for Applications Using Approved Hash Algorithms Quynh Dang Computer Security Division Information Technology Laboratory C O M P U T E R S E C U R I T Y February
More informationIntroduction to Symmetric and Asymmetric Cryptography
Introduction to Symmetric and Asymmetric Cryptography Ali E. Abdallah Birmingham CityUniversity Email: Ali.Abdallah@bcu.ac.uk Lectures are part of the project: ConSoLiDatE Multidisciplinary Cooperation
More informationSecurity and Cryptography just by images
Security and Cryptography just by images Pascal Lafourcade 2009 pascal.lafourcade@imag.fr 1 / 52 Motivations Applications 2 / 52 Motivations Secrecy or Confidentiality Alice communicates with the White
More informationSecurity and Cryptography 1. Stefan Köpsell, Thorsten Strufe. Module 4: Basic Crypto, Stream Ciphers
Security and Cryptography 1 Stefan Köpsell, Thorsten Strufe Module 4: Basic Crypto, Stream Ciphers Disclaimer: Günter Schäfer, Mark Manulis, large parts from Dan Boneh Dresden, WS 16/17 Reprise from the
More informationOverview. SSL Cryptography Overview CHAPTER 1
CHAPTER 1 Note The information in this chapter applies to both the ACE module and the ACE appliance unless otherwise noted. The features in this chapter apply to IPv4 and IPv6 unless otherwise noted. Secure
More information