Security Handshake Pitfalls
|
|
- Shanon Norman
- 5 years ago
- Views:
Transcription
1 Security Handshake Pitfalls Ahmet Burak Can Hacettepe University 1
2 Cryptographic Authentication Password authentication is subject to eavesdropping Alternative: Cryptographic challenge-response Symmetric key Public key 2
3 Symmetric Key Challenge-Response An example protocol: I m a challenge R F(K AB,R) Authentication not mutual (login only) Subject to connection hijacking (login only) Subject to off-line password guessing (if K is derived from password) s database has keys in the clear 3
4 Symmetric Key Challenge-Response An alternative protocol: I m K AB {R} R Requires reversible cryptography Subject to dictionary attack, without eavesdropping, if R is recognizable Can be used for mutual authentication if R is recognizable and has limited lifetime 4
5 Symmetric Key Challenge-Response A one-message protocol: I m, K AB {timestamp} Easy integration into password-sending systems More efficient: Single message, stateless Care needed against replays: timeout needed Care needed if key is common across servers Clock has to be protected as well Alternatively, with a hash function, send, I m, timestamp, H(K AB,timestamp) 5
6 Public Key Challenge-Response By signature: I m R [R] A 6
7 Public Key Challenge-Response By decryption: I m {R} A R Problem: (or Trudy) can get to sign/decrypt any text he chooses. Solutions: Never use the same key for different purposes (e.g., for login and signature) Use formatted challenges 7
8 Mutual Authentication An example protocol: I m R 1 F(K AB,R 1 ) R 2 F(K AB,R 2 ) 8
9 Mutual Authentication with Few Messages Number of messages for mutual authentication can be reduced: I m, R 2 R 1, F(K AB,R 2 ) F(K AB,R 1 ) However, this protocol is vulnerable to Reflection attack Dictionary attack :Trudy can do dictionary attack against K AB acting as, without eavesdropping. 9
10 Reflection Attack: Original session: I m, R 2 Trudy R 1, F(K AB,R 2 ) F(K AB,R 1 ) Decoy session: I m, R 1 Trudy R 3, F(K AB,R 1 ) 10
11 Results from Reflection Attack Solutions: Different keys for and Formatted challenges, different for and Principle: Initiator should be the first to prove its identity 11
12 A Modified Mutual Authentication Scheme Solution against both problems: I m R 1 F(K AB,R 1 ), R 2 F(K AB,R 2 ) Dictionary attack is still possible if Trudy can impersonate. 12
13 Mutual Authentication with Public Keys I m, {R 2 } B R 2, {R 1 } A R 1 Problem: How can the public/private keys be remembered by ordinary users? Possibly, they can be retrieved from a server with password based authentication & encryption. 13
14 Session Key Establishment A session key is needed for integrity protection and encryption in a communication session. It must be different for each session unguessable by an eavesdropper not K AB {x} for some x predictable/extractable by an attacker Session keys can be established by using Symmetric encryption Public key encryption 14
15 Session Key Establishment with Symmetric Encryption I m R K AB {R} Do not use K AB {R} or K AB {R+1} Take (K AB +1){R} as the session key. I m R+1 K AB {R+1} 15
16 Session Key Establishment with Public Key Cryptosystem An alternative is to use Diffie-Helman key exchange algorithm. Another alternative with PKC, send additional random nonces {R} A, {R} B and use them to derive a session key. {R 1 } B {R 2 } A K R 1 R 2 = K = R 1 R2 16
17 Key Establishment and Authentication with KDC A simple protocol:, K A {, K AB } KDC K B {, K AB } Problem: Potential delayed key delivery to. (besides others) 17
18 Key Establishment and Authentication with KDC Another simple protocol:, K A {, K AB }, ticket B where ticket B = K B {, K AB } KDC, ticket B Problems: No freshness guarantee for K AB & need to authenticate 18
19 Nonces Nonce: Something created for one particular occasion Nonce types: Random numbers Timestamps Sequence numbers Random nonces needed for unpredictability Obtaining random nonces from timestamps: encryption with a secret key. 19
20 Needham-Schroeder Protocol N 1,, K A {N 1,, K AB, ticket B } where ticket B = K B {K AB, } KDC ticket B, K AB {N 2 } K AB {N 2-1, N 3 } K AB {N 3-1} 20
21 Needham-Schroeder Protocol Ticket is double-encrypted. (unnecessary) N 1 : for authenticating KDC & freshness of K AB. N 2, N 3 : for key confirmation, mutual authentication Why are the challenges N 2, N 3 encrypted? Problem: doesn t have freshness guarantee for K AB (i.e., can t detect replays). 21
22 Replaying Tickets Messages should be integrity protected. Otherwise, cutand-paste reflection attacks possible: replay ticket B, K AB {N 2 } Trudy K AB {N 2-1, N 3 } K AB {N 3-1} ticket B, K AB {N 3 } Trudy K AB {N 3-1, N 4 } 22
23 Expanded Needham-Schroeder Protocol hello K B {N B } N 1,,, K B {N B } K A {N 1,, K AB, ticket B } where ticket B = K B {K AB,, N B } KDC ticket B, K AB {N 2 } K AB {N 2-1, N 3 } K AB {N 3-1} 23
24 Protocol Performance Comparison Computational Complexity: (to minimize CPU time, power consumption) Number of private-key operations public-key bytes encrypted with secret key bytes hashed Communication Complexity: Number of message rounds Bandwidth consumption 24
Security Handshake Pitfalls
Cryptographic Authentication Security Handshake Pitfalls Ahmet Burak Can Hacettepe University abc@hacettepe.edu.tr Password authentication is subject to eavesdropping Alternative: Cryptographic challenge-response
More informationOutline. Login w/ Shared Secret: Variant 1. Login With Shared Secret: Variant 2. Login Only Authentication (One Way) Mutual Authentication
Outline Security Handshake Pitfalls (Chapter 11 & 12.2) Login Only Authentication (One Way) Login i w/ Shared Secret One-way Public Key Lamport s Hash Mutual Authentication Shared Secret Public Keys Timestamps
More informationCSC 474/574 Information Systems Security
CSC 474/574 Information Systems Security Topic 3.3: Security Handshake Pitfalls CSC 474/574 Dr. Peng Ning 1 Authentication Handshakes Secure communication almost always includes an initial authentication
More informationAuthentication Handshakes
AIT 682: Network and Systems Security Topic 6.2 Authentication Protocols Instructor: Dr. Kun Sun Authentication Handshakes Secure communication almost always includes an initial authentication handshake.
More informationDr. Jinyuan (Stella) Sun Dept. of Electrical Engineering and Computer Science University of Tennessee Fall 2010
CS 494/594 Computer and Network Security Dr. Jinyuan (Stella) Sun Dept. of Electrical Engineering and Computer Science University of Tennessee Fall 2010 1 Security Handshake Pitfalls Login only Mutual
More informationSecurity Handshake Pitfalls
Hello Challenge R f(k, R f(k, R Problems: 1. Authentication is not mutual only authenticates Anyone can send the challenge R. f(k, R Problems: 1. Authentication is not mutual only authenticates Anyone
More informationSecurity Handshake Pitfalls
Security Handshake Pitfalls 1 Authentication Handshakes Secure communication almost always includes an initial authentication handshake: Authenticate each other Establish sessions keys This process may
More information6. Security Handshake Pitfalls Contents
Contents 1 / 45 6.1 Introduction 6.2 Log-in Only 6.3 Mutual Authentication 6.4 Integrity/Encryption of Data 6.5 Mediated Authentication (with KDC) 6.6 Bellovin-Merrit 6.7 Network Log-in and Password Guessing
More informationCIS 6930/4930 Computer and Network Security. Topic 6.2 Authentication Protocols
CIS 6930/4930 Computer and Network Security Topic 6.2 Authentication Protocols 1 Authentication Handshakes Secure communication almost always includes an initial authentication handshake. Authenticate
More informationCSCI 667: Concepts of Computer Security. Lecture 9. Prof. Adwait Nadkarni
CSCI 667: Concepts of Computer Security Lecture 9 Prof. Adwait Nadkarni 1 Derived from slides by William Enck, Micah Sherr, Patrick McDaniel, Peng Ning, and Vitaly Shmatikov Authentication Alice? Bob?
More information0/41. Alice Who? Authentication Protocols. Andreas Zeller/Stephan Neuhaus. Lehrstuhl Softwaretechnik Universität des Saarlandes, Saarbrücken
0/41 Alice Who? Authentication Protocols Andreas Zeller/Stephan Neuhaus Lehrstuhl Softwaretechnik Universität des Saarlandes, Saarbrücken The Menu 1/41 Simple Authentication Protocols The Menu 1/41 Simple
More information10/1/2015. Authentication. Outline. Authentication. Authentication Mechanisms. Authentication Mechanisms. Authentication Mechanisms
Authentication IT443 Network Security Administration Instructor: Bo Sheng Authentication Mechanisms Key Distribution Center and Certificate Authorities Session Key 1 2 Authentication Authentication is
More informationProtocols II. Computer Security Lecture 12. David Aspinall. 17th February School of Informatics University of Edinburgh
Protocols II Computer Security Lecture 12 David Aspinall School of Informatics University of Edinburgh 17th February 2011 Outline Introduction Shared-key Authentication Asymmetric authentication protocols
More informationPassword. authentication through passwords
Password authentication through passwords Human beings Short keys; possibly used to generate longer keys Dictionary attack: adversary tries more common keys (easy with a large set of users) Trojan horse
More informationTest 2 Review. (b) Give one significant advantage of a nonce over a timestamp.
Test 2 Review Name Student ID number Notation: {X} Bob Apply Bob s public key to X [Y ] Bob Apply Bob s private key to Y E(P, K) Encrypt P with symmetric key K D(C, K) Decrypt C with symmetric key K h(x)
More informationAuthentication. Strong Password Protocol. IT352 Network Security Najwa AlGhamdi
Authentication Strong Password Protocol 1 Strong Password Protocol Scenario : Alice uses any workstation to log to the server B, using a password to authenticate her self. Various way to do that? Use Ur
More informationCryptography CS 555. Topic 16: Key Management and The Need for Public Key Cryptography. CS555 Spring 2012/Topic 16 1
Cryptography CS 555 Topic 16: Key Management and The Need for Public Key Cryptography CS555 Spring 2012/Topic 16 1 Outline and Readings Outline Private key management between two parties Key management
More informationCIS 6930/4930 Computer and Network Security. Topic 7. Trusted Intermediaries
CIS 6930/4930 Computer and Network Security Topic 7. Trusted Intermediaries 1 Trusted Intermediaries Problem: authentication for large networks Solution #1 Key Distribution Center (KDC) Representative
More informationAuthentication Protocols. Outline. Who Is Authenticated?
Authentication Protocols Guevara Noubir College of Computer and Information Science Northeastern University noubir@ccs.neu.edu Outline Overview of Authentication Systems [Chapter 9] Authentication of People
More informationSession key establishment protocols
our task is to program a computer which gives answers which are subtly and maliciously wrong at the most inconvenient possible moment. -- Ross Anderson and Roger Needham, Programming Satan s computer Session
More informationSession key establishment protocols
our task is to program a computer which gives answers which are subtly and maliciously wrong at the most inconvenient possible moment. -- Ross Anderson and Roger Needham, Programming Satan s computer Session
More informationCryptographic Protocols 1
Cryptographic Protocols 1 Luke Anderson luke@lukeanderson.com.au 5 th May 2017 University Of Sydney Overview 1. Crypto-Bulletin 2. Problem with Diffie-Hellman 2.1 Session Hijacking 2.2 Encrypted Key Exchange
More informationHOST Authentication Overview ECE 525
Authentication Overview Authentication refers to the process of verifying the identity of the communicating principals to one another Usually sub-divided into Entity authentication Authentication in real-time
More informationSecurity and Privacy in Computer Systems. Lecture 7 The Kerberos authentication system. Security policy, security models, trust Access control models
CS 645 Security and Privacy in Computer Systems Lecture 7 The Kerberos authentication system Last Week Security policy, security models, trust Access control models The Bell-La Padula (BLP) model The Biba
More informationCS 470 Spring Security. Mike Lam, Professor. a.k.a. Why on earth do Alice and Bob need to talk so much?!? Content taken from the following:
50fb6be35f4c3105 9d4ed08fb86d8887 b746c452a9c9443b 15b22f450c76218e CS 470 Spring 2017 9df7031cdbff9d10 b700a92855f16328 5b757e66d2131841 62fedd7d9131e42e Mike Lam, Professor Security a.k.a. Why on earth
More informationIssues. Separation of. Distributed system security. Security services. Security policies. Security mechanism
Module 9 - Security Issues Separation of Security policies Precise definition of which entities in the system can take what actions Security mechanism Means of enforcing that policy Distributed system
More informationLecture 5: Protocols - Authentication and Key Exchange* CS 392/6813: Computer Security Fall Nitesh Saxena
Lecture 5: Protocols - Authentication and Key Exchange* CS 392/6813: Computer Security Fall 2009 Nitesh Saxena *Adopted from a previous lecture by Gene Tsudik Course Admin HW3 Problem 3 due Friday midnight
More informationUser Authentication. Modified By: Dr. Ramzi Saifan
User Authentication Modified By: Dr. Ramzi Saifan Authentication Verifying the identity of another entity Computer authenticating to another computer Person authenticating to a local/remote computer Important
More informationNetwork Security CHAPTER 31. Solutions to Review Questions and Exercises. Review Questions
CHAPTER 3 Network Security Solutions to Review Questions and Exercises Review Questions. A nonce is a large random number that is used only once to help distinguish a fresh authentication request from
More informationReal-time protocol. Chapter 16: Real-Time Communication Security
Chapter 16: Real-Time Communication Security Mohammad Almalag Dept. of Computer Science Old Dominion University Spring 2013 1 Real-time protocol Parties negotiate interactively (Mutual) Authentication
More informationIdeal Security Protocol. Identify Friend or Foe (IFF) MIG in the Middle 4/2/2012
Ideal Security Protocol Satisfies security requirements Requirements must be precise Efficient Small computational requirement Small bandwidth usage, network delays Not fragile Works when attacker tries
More informationECE596C: Handout #9. Authentication Using Shared Secrets. Electrical and Computer Engineering, University of Arizona, Loukas Lazos
ECE596C: Handout #9 Authentication Using Shared Secrets Electrical and Computer Engineering, University of Arizona, Loukas Lazos Abstract. In this lecture we introduce the concept of authentication and
More informationCS 470 Spring Security. Mike Lam, Professor. a.k.a. Why on earth do Alice and Bob need to share so many secrets?!?
50fb6be35f4c3105 9d4ed08fb86d8887 b746c452a9c9443b 15b22f450c76218e CS 470 Spring 2018 9df7031cdbff9d10 b700a92855f16328 5b757e66d2131841 62fedd7d9131e42e Mike Lam, Professor Security a.k.a. Why on earth
More informationTest 2 Review. 1. (10 points) Timestamps and nonces are both used in security protocols to prevent replay attacks.
Test 2 Review Name Student ID number Notation: {X} Bob Apply Bob s public key to X [Y ] Bob Apply Bob s private key to Y E(P, K) Encrypt P with symmetric key K D(C, K) Decrypt C with symmetric key K h(x)
More informationCryptographic Checksums
Cryptographic Checksums Mathematical function to generate a set of k bits from a set of n bits (where k n). k is smaller then n except in unusual circumstances Example: ASCII parity bit ASCII has 7 bits;
More informationCristina Nita-Rotaru. CS355: Cryptography. Lecture 17: X509. PGP. Authentication protocols. Key establishment.
CS355: Cryptography Lecture 17: X509. PGP. Authentication protocols. Key establishment. Public Keys and Trust Public Key:P A Secret key: S A Public Key:P B Secret key: S B How are public keys stored How
More informationUser Authentication. Modified By: Dr. Ramzi Saifan
User Authentication Modified By: Dr. Ramzi Saifan Authentication Verifying the identity of another entity Computer authenticating to another computer Person authenticating to a local/remote computer Important
More informationCS 494/594 Computer and Network Security
CS 494/594 Computer and Network Security Dr. Jinyuan (Stella) Sun Dept. of Electrical Engineering and Computer Science University of Tennessee Fall 2010 1 Real-Time Communication Security Network layers
More informationUser Authentication Protocols
User Authentication Protocols Class 5 Stallings: Ch 15 CIS-5370: 26.September.2016 1 Announcement Homework 1 is due today by end of class CIS-5370: 26.September.2016 2 User Authentication The process of
More informationStrong Password Protocols
Strong Password Protocols Strong Password Protocols Password authentication over a network Transmit password in the clear. Open to password sniffing. Open to impersonation of server. Do Diffie-Hellman
More informationTrusted Intermediaries
AIT 682: Network and Systems Security Topic 7. Trusted Intermediaries Instructor: Dr. Kun Sun Trusted Intermediaries Problem: authentication for large networks Solution #1 Key Distribution Center (KDC)
More informationAIT 682: Network and Systems Security
AIT 682: Network and Systems Security Topic 7. Trusted Intermediaries Instructor: Dr. Kun Sun Trusted Intermediaries Problem: authentication for large networks Solution #1 Key Distribution Center (KDC)
More information1.264 Lecture 27. Security protocols Symmetric cryptography. Next class: Anderson chapter 10. Exercise due after class
1.264 Lecture 27 Security protocols Symmetric cryptography Next class: Anderson chapter 10. Exercise due after class 1 Exercise: hotel keys What is the protocol? What attacks are possible? Copy Cut and
More informationL13. Reviews. Rocky K. C. Chang, April 10, 2015
L13. Reviews Rocky K. C. Chang, April 10, 2015 1 Foci of this course Understand the 3 fundamental cryptographic functions and how they are used in network security. Understand the main elements in securing
More informationKey Establishment and Authentication Protocols EECE 412
Key Establishment and Authentication Protocols EECE 412 1 where we are Protection Authorization Accountability Availability Access Control Data Protection Audit Non- Repudiation Authentication Cryptography
More informationData Security and Privacy. Topic 14: Authentication and Key Establishment
Data Security and Privacy Topic 14: Authentication and Key Establishment 1 Announcements Mid-term Exam Tuesday March 6, during class 2 Need for Key Establishment Encrypt K (M) C = Encrypt K (M) M = Decrypt
More informationUNIT - IV Cryptographic Hash Function 31.1
UNIT - IV Cryptographic Hash Function 31.1 31-11 SECURITY SERVICES Network security can provide five services. Four of these services are related to the message exchanged using the network. The fifth service
More informationCryptography and Network Security
Cryptography and Network Security Third Edition by William Stallings Lecture slides by Lawrie Brown Chapter 14 Authentication Applications We cannot enter into alliance with neighbouring princes until
More informationUser Authentication Protocols Week 7
User Authentication Protocols Week 7 CEN-5079: 2.October.2017 1 Announcement Homework 1 is posted on the class webpage Due in 2 weeks 10 points (out of 100) subtracted each late day CEN-5079: 2.October.2017
More informationLecture 1: Course Introduction
Lecture 1: Course Introduction Thomas Johansson T. Johansson (Lund University) 1 / 37 Chapter 9: Symmetric Key Distribution To understand the problems associated with managing and distributing secret keys.
More informationAcknowledgments. CSE565: Computer Security Lectures 16 & 17 Authentication & Applications
CSE565: Computer Security Lectures 16 & 17 Authentication & Applications Shambhu Upadhyaya Computer Science & Eng. University at Buffalo Buffalo, New York 14260 Lec 16.1 Acknowledgments Material for some
More informationDistributed Systems. 25. Authentication Paul Krzyzanowski. Rutgers University. Fall 2018
Distributed Systems 25. Authentication Paul Krzyzanowski Rutgers University Fall 2018 2018 Paul Krzyzanowski 1 Authentication For a user (or process): Establish & verify identity Then decide whether to
More informationUnit-VI. User Authentication Mechanisms.
Unit-VI User Authentication Mechanisms Authentication is the first step in any cryptographic solution Authentication can be defined as determining an identity to the required level of assurance Passwords
More information(2½ hours) Total Marks: 75
(2½ hours) Total Marks: 75 N. B.: (1) All questions are compulsory. (2) Makesuitable assumptions wherever necessary and state the assumptions made. (3) Answers to the same question must be written together.
More informationCS November 2018
Authentication Distributed Systems 25. Authentication For a user (or process): Establish & verify identity Then decide whether to allow access to resources (= authorization) Paul Krzyzanowski Rutgers University
More informationIntroduction. Trusted Intermediaries. CSC/ECE 574 Computer and Network Security. Outline. CSC/ECE 574 Computer and Network Security.
Trusted Intermediaries CSC/ECE 574 Computer and Network Security Topic 7. Trusted Intermediaries Problem: authentication for large networks Solution #1 Key Distribution Center () Representative solution:
More informationCryptography & Key Exchange Protocols. Faculty of Computer Science & Engineering HCMC University of Technology
Cryptography & Key Exchange Protocols Faculty of Computer Science & Engineering HCMC University of Technology Outline 1 Cryptography-related concepts 2 3 4 5 6 7 Key channel for symmetric cryptosystems
More informationCryptography and Network Security. Prof. D. Mukhopadhyay. Department of Computer Science and Engineering. Indian Institute of Technology, Kharagpur
Cryptography and Network Security Prof. D. Mukhopadhyay Department of Computer Science and Engineering Indian Institute of Technology, Kharagpur Module No. # 01 Lecture No. # 38 A Tutorial on Network Protocols
More informationSecurity: Focus of Control. Authentication
Security: Focus of Control Three approaches for protection against security threats a) Protection against invalid operations b) Protection against unauthorized invocations c) Protection against unauthorized
More informationComputer Security. 08r. Pre-exam 2 Last-minute Review Cryptography. Paul Krzyzanowski. Rutgers University. Spring 2018
Computer Security 08r. Pre-exam 2 Last-minute Review Cryptography Paul Krzyzanowski Rutgers University Spring 2018 March 26, 2018 CS 419 2018 Paul Krzyzanowski 1 Cryptographic Systems March 26, 2018 CS
More informationCSC/ECE 774 Advanced Network Security
Computer Science CSC/ECE 774 Advanced Network Security Topic 2. Network Security Primitives CSC/ECE 774 Dr. Peng Ning 1 Outline Absolute basics Encryption/Decryption; Digital signatures; D-H key exchange;
More informationIdentification Schemes
Identification Schemes Lecture Outline Identification schemes passwords one-time passwords challenge-response zero knowledge proof protocols Authentication Data source authentication (message authentication):
More information1 Identification protocols
ISA 562: Information Security, Theory and Practice Lecture 4 1 Identification protocols Now that we know how to authenticate messages using MACs, a natural question is, how can we use MACs to prove that
More informationNetwork Security Chapter 8
Network Security Chapter 8 Cryptography Symmetric-Key Algorithms Public-Key Algorithms Digital Signatures Management of Public Keys Communication Security Authentication Protocols Email Security Web Security
More informationCIS 6930/4930 Computer and Network Security. Final exam review
CIS 6930/4930 Computer and Network Security Final exam review About the Test This is an open book and open note exam. You are allowed to read your textbook and notes during the exam; You may bring your
More informationComputer Security 4/12/19
Authentication Computer Security 09. Authentication Identification: who are you? Authentication: prove it Authorization: you can do it Paul Krzyzanowski Protocols such as Kerberos combine all three Rutgers
More informationNetwork Security (NetSec)
Chair of Network Architectures and Services Department of Informatics Technical University of Munich Network Security (NetSec) IN2101 WS 17/18 Prof. Dr.-Ing. Georg Carle Dr. Heiko Niedermayer Cornelius
More informationL7: Key Distributions. Hui Chen, Ph.D. Dept. of Engineering & Computer Science Virginia State University Petersburg, VA 23806
L7: Key Distributions Hui Chen, Ph.D. Dept. of Engineering & Computer Science Virginia State University Petersburg, VA 23806 9/16/2015 CSCI 451 - Fall 2015 1 Acknowledgement Many slides are from or are
More informationModelling and Analysing of Security Protocol: Lecture 1. Introductions to Modelling Protocols. Tom Chothia CWI
Modelling and Analysing of Security Protocol: Lecture 1 Introductions to Modelling Protocols Tom Chothia CWI This Course This course will primarily teaching you: How to design your own secure communication
More informationMessage authentication
Message authentication -- Reminder on hash unctions -- MAC unctions hash based block cipher based -- Digital signatures (c) Levente Buttyán (buttyan@crysys.hu) Hash unctions a hash unction is a unction
More informationLecture 19: cryptographic algorithms
Lecture 19: cryptographic algorithms Operating Systems and Networks Behzad Bordbar School of Computer Science, University of Birmingham, UK 179 Overview Cryptographic algorithms symmetric: TEA asymmetric:
More informationSecurity: Focus of Control
Security: Focus of Control Three approaches for protection against security threats a) Protection against invalid operations b) Protection against unauthorized invocations c) Protection against unauthorized
More informationAuthentication in Distributed Systems
Authentication in Distributed Systems Introduction Crypto transforms (communications) security problems into key management problems. To use encryption, digital signatures, or MACs, the parties involved
More informationNetwork Security. Kerberos and other Frameworks for Client Authentication. Dr. Heiko Niedermayer Cornelius Diekmann. Technische Universität München
Network Security Kerberos and other Frameworks for Client Authentication Dr. Heiko Niedermayer Cornelius Diekmann Lehrstuhl für Netzarchitekturen und Netzdienste Institut für Informatik Version: January
More informationLecture 15: Cryptographic algorithms
06-06798 Distributed Systems Lecture 15: Cryptographic algorithms 22 March, 2002 1 Overview Cryptographic algorithms symmetric: TEA asymmetric: RSA Digital signatures digital signatures with public key
More informationAuthentication in real world: Kerberos, SSH and SSL. Zheng Ma Apr 19, 2005
Authentication in real world: Kerberos, SSH and SSL Zheng Ma Apr 19, 2005 Where are we? After learning all the foundation of modern cryptography, we are ready to see some real world applications based
More informationElements of Cryptography and Computer and Network Security Computer Science 134 (COMPSCI 134) Fall 2016 Instructor: Karim ElDefrawy
Elements of Cryptography and Computer and Network Security Computer Science 134 (COMPSCI 134) Fall 2016 Instructor: Karim ElDefrawy Homework 3 Due: Monday, 11/28/2016 at 11:55pm PT Solution: Will be posted
More informationCSC 774 Network Security
CSC 774 Network Security Topic 2. Review of Cryptographic Techniques CSC 774 Dr. Peng Ning 1 Outline Encryption/Decryption Digital signatures Hash functions Pseudo random functions Key exchange/agreement/distribution
More informationLecture 9. Authentication & Key Distribution
Lecture 9 Authentication & Key Distribution 1 Where are we now? We know a bit of the following: Conventional (symmetric) cryptography Hash functions and MACs Public key (asymmetric) cryptography Encryption
More informationKurose & Ross, Chapters (5 th ed.)
Kurose & Ross, Chapters 8.2-8.3 (5 th ed.) Slides adapted from: J. Kurose & K. Ross \ Computer Networking: A Top Down Approach (5 th ed.) Addison-Wesley, April 2009. Copyright 1996-2010, J.F Kurose and
More informationCPSC 467b: Cryptography and Computer Security
CPSC 467b: Cryptography and Computer Security Michael J. Fischer Lecture 24 April 16, 2012 CPSC 467b, Lecture 24 1/33 Kerberos Secure Shell (SSH) Transport Layer Security (TLS) Digital Rights Management
More informationLecture Nov. 21 st 2006 Dan Wendlandt ISP D ISP B ISP C ISP A. Bob. Alice. Denial-of-Service. Password Cracking. Traffic.
15-441 Lecture Nov. 21 st 2006 Dan Wendlandt Worms & Viruses Phishing End-host impersonation Denial-of-Service Route Hijacks Traffic modification Spyware Trojan Horse Password Cracking IP Spoofing DNS
More informationCSC 482/582: Computer Security. Security Protocols
Security Protocols Topics 1. Basic Concepts of Cryptography 2. Security Protocols 3. Authentication Protocols 4. Key Exchange Protocols 5. Kerberos 6. Public Key Infrastructure Encryption and Decryption
More informationICT 6541 Applied Cryptography Lecture 8 Entity Authentication/Identification
ICT 6541 Applied Cryptography Lecture 8 Entity Authentication/Identification Hossen Asiful Mustafa Introduction Entity Authentication is a technique designed to let one party prove the identity of another
More informationAuthentication. Overview of Authentication systems. IT352 Network Security Najwa AlGhamdi
Authentication Overview of Authentication systems 1 Approaches for Message Authentication Authentication is process of reliably verifying the identity of someone. Authentication Schemes 1. Password-based
More informationCS /29/17. Paul Krzyzanowski 1. Fall 2016: Question 2. Distributed Systems. Fall 2016: Question 2 (cont.) Fall 2016: Question 3
Fall 2016: Question 2 You have access to a file of class enrollment lists. Each line contains {course_number, student_id}. Distributed Systems 2017 Pre-exam 3 review Selected questions from past exams
More informationComputer Networks. Wenzhong Li. Nanjing University
Computer Networks Wenzhong Li Nanjing University 1 Chapter 7. Network Security Network Attacks Cryptographic Technologies Message Integrity and Authentication Key Distribution Firewalls Transport Layer
More informationInformation Security CS 526
Information Security CS 526 Topic 14: Key Distribution & Agreement, Secure Communication Topic 14: Secure Communication 1 Readings for This Lecture On Wikipedia Needham-Schroeder protocol (only the symmetric
More informationCS 161 Computer Security
Paxson Spring 2011 CS 161 Computer Security Discussion 9 March 30, 2011 Question 1 Another Use for Hash Functions (8 min) The traditional Unix system for password authentication works more or less like
More informationCSCE 813 Internet Security Kerberos
CSCE 813 Internet Security Kerberos Professor Lisa Luo Fall 2017 What is Kerberos? An authentication server system from MIT; versions 4 and 5 Provide authentication for a user that works on a workstation
More informationSpring 2010: CS419 Computer Security
Spring 2010: CS419 Computer Security Vinod Ganapathy Lecture 7 Topic: Key exchange protocols Material: Class handout (lecture7_handout.pdf) Chapter 2 in Anderson's book. Today s agenda Key exchange basics
More informationSecuring Internet Communication: TLS
Securing Internet Communication: TLS CS 161: Computer Security Prof. David Wagner March 11, 2016 Today s Lecture Applying crypto technology in practice Two simple abstractions cover 80% of the use cases
More informationElements of Cryptography and Computer and Network Security Computer Science 134 (COMPSCI 134) Fall 2016 Instructor: Karim ElDefrawy
Elements of Cryptography and Computer and Network Security Computer Science 134 (COMPSCI 134) Fall 2016 Instructor: Karim ElDefrawy Homework 3 Due: Monday, 11/28/2016 at 11:55pm PT Solution: Will be posted
More information5. Authentication Contents
Contents 1 / 47 Introduction Password-based Authentication Address-based Authentication Cryptographic Authentication Protocols Eavesdropping and Server Database Reading Trusted Intermediaries Session Key
More informationElements of Security
Elements of Security Dr. Bill Young Department of Computer Sciences University of Texas at Austin Last updated: April 8, 2015 at 12:47 Slideset 7: 1 Car Talk Puzzler You have a friend in a police state
More informationח'/סיון/תשע "א. RSA: getting ready. Public Key Cryptography. Public key cryptography. Public key encryption algorithms
Public Key Cryptography Kurose & Ross, Chapters 8.28.3 (5 th ed.) Slides adapted from: J. Kurose & K. Ross \ Computer Networking: A Top Down Approach (5 th ed.) AddisonWesley, April 2009. Copyright 19962010,
More informationCS Protocol Design. Prof. Clarkson Spring 2017
CS 5430 Protocol Design Prof. Clarkson Spring 2017 Review Cryptography: Encryption, block ciphers, block cipher modes, MACs, cryptographic hash functions, digital signatures, authenticated encryption,
More informationAIT 682: Network and Systems Security
AIT 682: Network and Systems Security Final Exam Review Instructor: Dr. Kun Sun Topics covered by Final Topic before Midterm 10% Topic after Midterm 90% Date: 12/13/2017 7:30am 10:15am Place: the same
More informationA Two-Fold Authentication Mechanism for Network Security
Asian Journal of Engineering and Applied Technology ISSN 2249-068X Vol. 7 No. 2, 2018, pp. 86-90 The Research Publication, www.trp.org.in A Two-Fold for Network Security D. Selvamani 1 and V Selvi 2 1
More informationA SECURE PASSWORD-BASED REMOTE USER AUTHENTICATION SCHEME WITHOUT SMART CARDS
ISSN 1392 124X INFORMATION TECHNOLOGY AND CONTROL, 2012, Vol.41, No.1 A SECURE PASSWORD-BASED REMOTE USER AUTHENTICATION SCHEME WITHOUT SMART CARDS Bae-Ling Chen 1, Wen-Chung Kuo 2*, Lih-Chyau Wuu 3 1
More information