Prof. Jk LEE/security1 Secure Encryption Systems 암호화복호화 공통비밀키 암호시스템.

Slides:

Advertisements

Similar presentations

Chapter 3 Public Key Cryptography and Message authentication.

Advertisements

Asymmetric Digital Signatures And Key Exchange Prof. Ravi Sandhu.

Asymmetric Encryption Prof. Ravi Sandhu. 2 © Ravi Sandhu PUBLIC KEY ENCRYPTION Encryption Algorithm E Decryption Algorithm D Plain- text Plain- text Ciphertext.

Public Key Cryptography Nick Feamster CS 6262 Spring 2009.

Cryptography and Network Security Chapter 9

Information Security & Cryptographic Principles. Infosec and Cryptography Subjects / Topics : 1. Introduction to computer cryptography 1. Introduction.

CSE331: Introduction to Networks and Security Lecture 19 Fall 2002.

22C:19 Discrete Structures Integers and Modular Arithmetic

22C:19 Discrete Math Integers and Modular Arithmetic Fall 2010 Sukumar Ghosh.

CS470, A.SelcukPublic Key Cryptography1 CS 470 Introduction to Applied Cryptography Instructor: Ali Aydin Selcuk.

Public Encryption: RSA

Cryptography1 CPSC 3730 Cryptography Chapter 9 Public Key Cryptography and RSA.

Cryptography Prof. Seth D. Bergmann Rowan University Computer Science.

Ref: Pfleeger96, Ch.31 NP-Complete Problems Reference: Pfleeger, Charles P., Security in Computing, 2nd Edition, Prentice Hall, 1996.

Chapter 3 Encryption Algorithms & Systems (Part C)

Fall 2010/Lecture 311 CS 426 (Fall 2010) Public Key Encryption and Digital Signatures.

Chapter 3 Encryption Algorithms & Systems (Part B)

Introduction to Computer and Network Security Iliano Cervesato 26 August 2008 – Modern Cryptography.

UMass Lowell Computer Science Analysis of Algorithms Prof. Karen Daniels Fall, 2001 Lecture 7 Tuesday, 11/6/01 Number-Theoretic Algorithms Chapter.

Introduction to Computer and Network Security Iliano Cervesato 2 September 2008 – Public-key Encryption.

Public Key Cryptography Bryan Pearsaul. Outline What is Cryptology? Symmetric Ciphers Asymmetric Ciphers Diffie-Hellman RSA (Rivest/Shamir/Adleman) Moral.

Public-Key Cryptography and RSA CSE 651: Introduction to Network Security.

Public Key Model 8. Cryptography part 2.

CSCI 398 Research Topics in Computer Science Yana Kortsarts Computer Science Department Widener University Chester, PA.

Chapter 12 Cryptography Explained. Search Problems Specified by an algorithm C Two inputs ◦ I is the instance. ◦ S is the solution. ◦ Must complete in.

© Neeraj Suri EU-NSF ICT March 2006 DEWSNet Dependable Embedded Wired/Wireless Networks MUET Jamshoro Computer Security: Principles and Practice Slides.

Prime Numbers Prime numbers only have divisors of 1 and self

Network and Communications Network Security Department of Computer Science Virginia Commonwealth University.

1 Network Security Lecture 6 Public Key Algorithms Waleed Ejaz

Computer System Security CSE 5339/7339

RSA Ramki Thurimella.

The Early Days of RSA -- History and Lessons Ronald L. Rivest MIT Lab for Computer Science ACM Turing Award Lecture.

Cryptography  Why Cryptography  Symmetric Encryption  Key exchange  Public-Key Cryptography  Key exchange  Certification.

1 Lecture 9 Public Key Cryptography Public Key Algorithms CIS CIS 5357 Network Security.

CSCE 201 Introduction to Information Security Fall 2010 Data Protection.

Midterm Review Cryptography & Network Security

Public Key Cryptography By: Noor Dhia Al- Shakarchy.

Public Key Encryption Terminology RSA Hash functions CSCE Farkas.

Public Key Encryption CS432 – Security in Computing Copyright © 2005, 2008 by Scott Orr and the Trustees of Indiana University.

Cryptography and Network Security Chapter 9 - Public-Key Cryptography

P1. Public-Key Cryptography and RSA 5351: Introduction to Cryptography Spring 2013.

CS461/ECE422 Spring 2012 Nikita Borisov — UIUC1.  Text Chapters 2 and 21  Handbook of Applied Cryptography, Chapter 8 

Computer Security: Principles and Practice First Edition by William Stallings and Lawrie Brown Lecture slides by Lawrie Brown Chapter 2 – Cryptographic.

Chapter 3 Encryption Algorithms & Systems. csci5233 computer security & integrity (Chap. 3) 2 Outline NP-completeness & Encryption Symmetric (secret key)

24-Nov-15Security Cryptography Cryptography is the science and art of transforming messages to make them secure and immune to attacks. It involves plaintext,

Chapter 3 Encryption Algorithms & Systems (Part D)

Chapter 3 – Public Key Cryptography and RSA (A). Private-Key Cryptography traditional private/secret/single-key cryptography uses one key shared by both.

COMP 424 Lecture 04 Advanced Encryption Techniques (DES, AES, RSA)

Encryption Basics Module 7 Section 2. History of Encryption Secret - NSA National Security Agency –has powerful computers - break codes –monitors all.

Public Key Cryptosystem Introduced in 1976 by Diffie and Hellman [2] In PKC different keys are used for encryption and decryption 1978: First Two Implementations.

Introduction to Cryptography Lecture 9. Public – Key Cryptosystems Each participant has a public key and a private key. It should be infeasible to determine.

Cryptography and Network Security Third Edition by William Stallings Lecture slides by Lawrie Brown.

Week 4 - Wednesday.  What did we talk about last time?  Finished DES  AES.

Introduction to Pubic Key Encryption CSCI 5857: Encoding and Encryption.

Public Key Cryptosystem In Symmetric or Private Key cryptosystems the encryption and decryption keys are either the same or can be easily found from each.

Security. Cryptography (1) Intruders and eavesdroppers in communication.

Cryptography Deffie hellman. organization Foundations Symmetric key Symmetric key weaknesses Assymmetric key Deffie hellman – key exchange RSA – public.

Hard Problems Some problems are hard to solve.  No polynomial time algorithm is known.  E.g., NP-hard problems such as machine scheduling, bin packing,

Lecture 5 Asymmetric Cryptography. Private-Key Cryptography Traditional private/secret/single key cryptography uses one key Shared by both sender and.

Digital Signatures.

Public Key Encryption.

Basics of Cryptography

Public Key Encryption and Digital Signatures

Public-Key Cryptography and RSA

RSA and El Gamal Cryptosystems

Private-Key Cryptography

Asymmetric Cryptography

ICS 353: Design and Analysis of Algorithms

Public-key encryption

Public Key Cryptography

Presentation transcript:

Prof. Jk LEE/security1 Secure Encryption Systems 암호화복호화 공통비밀키 암호시스템

Prof. Jk LEE/security2 3.Secure Encryption Systems  Symmetric encryption  Asymmetric encryption  Encryption algorithms DES,RSA and El Gamal  Hash algorithms  Clipper

Prof. Jk LEE/security3 Hard Problems:complexity  NP-complete problems:  easy to state,no hard understand, straight forward to solve  satisfiability: true or false  Knapsack: target  Clique: a graph in which each vertex is connected to every other vertex

Prof. Jk LEE/security4  Characteristics of NP-complete problems  The class P and NP  NP-completeness and Cryptography

Prof. Jk LEE/security5 Properties of Arithmetic  Primes  Greatest common divisor  Modular arithmetic  Properties of Modular Arithmetic  Fermat’s theorem  Algorithm for computing Inverses

Prof. Jk LEE/security6  Public key encryption Systems  Proposed by Diffie and Hellman 1976  Merkle-Hellman knapsacks  Rivest-Shamir-Adelman(RSA) Encryption  El Gamal and Digital Signature Algorithms  Hash Algorithms

Prof. Jk LEE/security7 Symmetric systems(SS) Symmetric systems(SS)  Single key system-->symmetric system  problem of ss:  if the key revealed?  Distribution of key?  The number of keys increase?  Weak about the attack?

Prof. Jk LEE/security8 DES( data Encryption Standard )  Developed by US gov. for use by the general public  Plain text:64bit  key: 56bit

Prof. Jk LEE/security9 Using Encryption:protocols and Practices

Prof. Jk LEE/security10 Distributed center for EI

Prof. Jk LEE/security11 Cycles of Substituition and Permutation

Prof. Jk LEE/security12 A Cycle in the DES

Prof. Jk LEE/security13

Prof. Jk LEE/security14

Prof. Jk LEE/security15

Prof. Jk LEE/security16 Key transformation

Prof. Jk LEE/security17

Prof. Jk LEE/security18 P-Boxs

Prof. Jk LEE/security19

Prof. Jk LEE/security20

Prof. Jk LEE/security21 Decryption Decryption

Prof. Jk LEE/security22 DES 에 관한 우려사항  56 비트 키 사용에 관한 우려  DES 알고리즘의 성질에 관한 우려