ROEVER ENGINEERING COLLEGE Elambalur,Perambalur DEPARTMENT OF CSE NP UNIT-I

Size: px
Start display at page:

Download "ROEVER ENGINEERING COLLEGE Elambalur,Perambalur DEPARTMENT OF CSE NP UNIT-I"

Transcription

1 1.List out the features of x.25 ROEVER ENGINEERING COLLEGE Elambalur,Perambalur DEPARTMENT OF CSE NP UNIT-I * Call control packets, used for setting up and clearing virtual circuits, are carried on the same channel and the same virtual circuit as data packets. In effect, inband signaling is used. * Multiplexing of virtual circuits takes place at layer 3. * Both layer 2 and layer 3 include flow control and error control mechanisms 2.what are the key difference between frame rely and x.25? * Call control signaling is carried on a separate logical connection from user data. Thus, intermediate nodes need not maintain state tables or process messages Relating to call control on an individual per-connection basis. * Multiplexing and switching of logical connections take place at layer 2 instead Of layer 3, eliminating one entire layer of processing. * There is no hop-by-hop flow control and error control. End-to-end flow control

2 And error control, if they are employed at all, are the responsibility of a higher layer. 3. Explain about the frame rely architecture. Frame rely architecture support two modes of operation that is two separate planes of operation: a control (C) plane, which is involved in the establishment and termination of logical connections, and a user (U) plane, which is responsible for the transfer of user data between subscribers. Thus, C-plane protocols are between a subscriber and the network, while U-plane protocols provide endto-end functionality 4. What are the core functions of LAPF? * Frame delimiting, alignment, and transparency * Frame multiplexing/demultiplexing using the address field * Inspection of the frame to ensure that it consists of an integral number of octets prior to zero-bit insertion or following zero-bit extraction * Inspection of the frame to ensure that it is neither too long nor too short * Detection of transmission errors * Congestion control functions *The last function listed above is new to LAPF

3 5. What is control plan? The control plane for frame-mode bearer services is similar to that for common channel Signaling in circuit-switching services, in that a separate logical channel used for control information. In the case of ISDN, control signaling is done over the D channel, to control the establishment and termination of frame-mode virtual calls on the D, B, and H channels (see Appendix A). At the data link layer, LAPD (Q.921) is used to provide a reliable data link control service, with error control and flow control, between user (TE) and network (NT) over the D channel. This data link service is used for the exchange of Q.933 control-signaling messages. 6. W hat is user plan? For the actual transfer of information between end users, the user-plane protocol is LAPF (Link Access Procedure for Frame-Mode Bearer Services), which is defined in Q.922. Q.922 is an enhanced version of LAPD (Q.921). Only the core functions of LAPF are used for frame relay: * Frame delimiting, alignment, and transparency * Frame multiplexing/demultiplexing using the address field * Inspection of the frame to ensure that it consists of an integral number of octets prior to zero-bit insertion or following zero-bit extraction * Inspection of the frame to ensure that it is neither too long nor too short * Detection of transmission errors * Congestion control functions

4 7. Give the various view point of ISDN? * Principles of ISDN * The user interface * Objectives * Services 8. List out the services of ISDN? 1. Support of voice and nonvoice applications using a limited set of Standardized Facilities 2. Support,for switched and nonswitched applications 3. Reliance on 64-kbps connections. 4. Intelligence in the network. 5. Layered protocol architecture. 9. List out the objectives of ISDN? Standardization Transparency. Separation of competitive functions.

5 eased and switched services. Cost-related tariffs.. Smooth migration. Multiplexed support. 10. List out the series of ISDN. * Series-General Concepts * Series-Service Capabilities * Series-Network Aspects * Series-User-Network Interfaces * Series-Internet work Interfaces * Series-Maintenance Principles 11. Give the types of ISDN channel. * B channel: 64 kbps * D channel: 16 or 64 kbps * H channel: 384(H0), 1536(H11), and 1920 (H12) kbps

6 12. What is B channel? The B channel is the basic user channel. It can be used to carry digital data, PCM-encoded digital voice, or a mixture of lower-rate traffic, including digital data and digitized voice encoded at a fraction of 64 kbps. In the case of mixed traffic, all traffic must be destined for the same endpoint. 13. How do you set up connection over B channel? * Circuit-switched. * Packet-switched. * Frame mode. * Semipermanent. 14. What is D channel? The D channel serves two purposes. First, it carries signaling information to control circuitswitched calls on associated B channels at the user interface. In addition, the D channel may be used for packet-switching or low-speed (e.g., 100 bps) telemetry at times when no signaling information is waiting. 15. What is H channel? H channels are provided for user information at higher bit rates. The user may employ such a channel as a high-speed trunk, or the channel may be subdivided according to the user's own TDM scheme.

7 Examples of applications include fast facsimile, video, high-speed data, high-quality audio, and multiple information streams at lower data rates. 16. How do you establish ISDN connection? ISDN provides four types of service for end-to-end communication: * Circuit-switched calls over a B channel. * Semi permanent connections over a B channel. * Packet-switched calls over a B channel. * Packet-switched calls over the D channel. UNIT-II 1.List out the features of x.25 * Call control packets, used for setting up and clearing virtual circuits, are carried on the same channel and the same virtual circuit as data packets. In effect, inband signaling is used. *Multiplexing of virtual circuits takes place at layer 3. *Both layer 2 and layer 3 include flow control and error control mechanisms 2.what are the key difference between frame rely and x.25? * Call control signaling is carried on a separate logical connection from user data.

8 Thus, intermediate nodes need not maintain state tables or process messages Relating to call control on an individual per-connection basis. * Multiplexing and switching of logical connections take place at layer 2 instead Of layer 3, eliminating one entire layer of processing. * There is no hop-by-hop flow control and error control. End-to-end flow control And error control, if they are employed at all, are the responsibility of a higher layer. 3. Explain about the frame rely architecture. Frame rely architecture support two modes of operation that is two separate planes of operation: a control (C) plane, which is involved in the establishment and termination of logical connections, and a user (U) plane, which is responsible for the transfer of user data between subscribers. Thus, C-plane protocols are between a subscriber and the network, while U-plane protocols provide endto-end functionality 4. What are the core functions of LAPF? * Frame delimiting, alignment, and transparency * Frame multiplexing/demultiplexing using the address field * Inspection of the frame to ensure that it consists of an integral number of octets prior to zero-bit insertion or following zero-bit extraction * Inspection of the frame to ensure that it is neither too long nor too short

9 * Detection of transmission errors * Congestion control functions *The last function listed above is new to LAPF, and 5. What is control plan? The control plane for frame-mode bearer services is similar to that for common channel Signaling in circuit-switching services, in that a separate logical channel used for control information. In the case of ISDN, control signaling is done over the D channel, to control the establishment and termination of framemode virtual calls on the D, B, and H channels (see Appendix A). At the data link layer, LAPD (Q.921) is used to provide a reliable data link control service, with error control and flow control, between user (TE) and network (NT) over the D channel. This data link service is used for the exchange of Q.933 control-signaling messages. 6. W hat is user plan? For the actual transfer of information between end users, the user-plane protocol is LAPF (Link Access Procedure for Frame-Mode Bearer Services), which is defined in Q.922. Q.922 is an enhanced version of LAPD (Q.921). Only the core functions of LAPF are used for frame relay: * Frame delimiting, alignment, and transparency

10 * Frame multiplexing/demultiplexing using the address field * Inspection of the frame to ensure that it consists of an integral number of octets prior to zero-bit insertion or following zero-bit extraction * Inspection of the frame to ensure that it is neither too long nor too short * Detection of transmission errors * Congestion control functions 7. Give the various view point of ISDN? * Principles of ISDN * The user interface * Objectives * Services 8. List out the services of ISDN? 1. Support of voice and nonvoice applications using a limited set of Standardized Facilities 2. Support,for switched and nonswitched applications

11 3. Reliance on 64-kbps connections. 4. Intelligence in the network. 5. Layered protocol architecture. 9. List out the objectives of ISDN? Standardization Transparency. Separation of competitive functions. eased and switched services. Cost-related tariffs.. Smooth migration. Multiplexed support. 10. List out the series of ISDN. * Series-General Concepts * Series-Service Capabilities * Series-Network Aspects

12 * Series-User-Network Interfaces * Series-Internet work Interfaces Series-Maintenance Principles 11. Give the types of ISDN channel. * B channel: 64 kbps * D channel: 16 or 64 kbps * H channel: 384(H0), 1536(H11), and 1920 (H12) kbps 12. What is B channel? The B channel is the basic user channel. It can be used to carry digital data, PCM-encoded digital voice, or a mixture of lower-rate traffic, including digital data and digitized voice encoded at a fraction of 64 kbps. In the case of mixed traffic, all traffic must be destined for the same endpoint. 13. How do you set up connection over B channel? * Circuit-switched. * Packet-switched. * Frame mode.

13 * Semipermanent. 14. What is D channel? The D channel serves two purposes. First, it carries signaling information to control circuit-switched calls on associated B channels at the user interface. In addition, the D channel may be used for packet-switching or low-speed (e.g., 100 bps) telemetry at times when no signaling information is waiting. 15. What is H channel? H channels are provided for user information at higher bit rates. The user may employ such a channel as a high-speed trunk, or the channel may be subdivided according to the user's own TDM scheme. Examples of applications include fast facsimile, video, high-speed data, highquality audio, and multiple information streams at lower data rates. 16. How do you establish ISDN connection? ISDN provides four types of service for end-to-end communication: * Circuit-switched calls over a B channel. * Semipermanent connections over a B channel. * Packet-switched calls over a B channel. * Packet-switched calls over the D channel.

14 UNIT-III 1. What are the essential ingredients of a symmetric cipher? It consists of five ingredients namely Plain text Encryption algorithm Secret key Cipher key Decryption algorithm 2. What are the two basic functions used in encryption algorithms? The two basic functions used in encryption algorithms are Substitution Transposition 3. How many keys are required for two people to communicate via a cipher? If both sender and receiver use the same key, the system is referred to as symmetric, single key, or conventional encryption. If the sender and receiver each use a different key, the system is referred to as asymmetric two-key, or public-key encryption 4. What is the difference between a block cipher and a stream cipher? A block cipher processes the input one block of elements at a time, producing an output block for each input block. A stream cipher processes the input elements continuously, producing output one element at a time, as it goes along.

15 5. What are the essential ingredients of a symmetric cipher? It consists of five ingredients namely Plain text Encryption algorithm Secret key Cipher key Decryption algorithm 6. how do you encryption and decryption are done using RSA crypto-system. RSA cryptosystem: 1. Generate two large random primes, p and q, of approximately equal size such that their product n=p q is of the required bit length. 2. Compute n=pq and and (o) phi=(p-1)(q-1). 3. Choose an integer e,1<e<phi, such that gcd(e,phi)=1. 4. Compute the secret exponent d,1<d<phi, such that ed=1 (mode phi). 5. The public key is(n,e) and the private key is (n,d). Keep all the values d,p,q and phi secret. 7.How do elliptic curve take part in encryption and decryption process? Encryption: Sender A does the following: 1. Obtain the recipint B s public key (n,e) 2. Represents the plaintext message a positive integer m. 3. Computes the ciphertext c=m mod n 4. Sends the ciphertext c to B 8. What is message authentication? It is a procedure that verifies whether the received message comes from assigned source has not been altered. It uses message authentication codes, hash algorithms to authenticate the message.

16 9. Define the classes of message authentication function. Message encryption: The entire cipher text would be used for authentication. Message Authentication Code: It is a function of message and secret key produce a fixed length value. Hash function: Some function that map a message of any length to fixed length which serves as authentication. 10. What are the requirements for message authentication? The requirements for message authentication are Disclosure: Traffic Analysis: Masquerade: Content modification:. Sequence modification: Timing modification: Source repudiation: Destination repudiation: 11. What you meant by hash function? Hash function accept a variable size message M as input and produces a fixed size hash code H(M) called as message digest as output. It is the variation on the message authentication code. 12. Differentiate MAC and Hash function? MAC: In Message Authentication Code, the secret key shared by sender and receiver. The MAC is appended to the message at the source at a time which the message is assumed or known to be correct. Hash Function: The hash value is appended to the message at the source at time when the message is assumed or known to be correct. The hash function itself not considered to be secret. 13. Any three hash algorithm. MD5 (Message Digest version 5) algorithm.

17 SHA_1 (Secure Hash Algorithm). RIPEMD_160 algorithm. 14. What are the requirements of the hash function? H can be applied to a block of data of any size. H produces a fixed length output. H(x) is relatively easy to compute for any given x, making both hardware and software implementations practical. 15. What you meant by MAC? MAC is Message Authentication Code. It is a function of message and secret key which produce a fixed length value called as MAC. MAC = CK (M) Where M K = variable length message = secret key shared by sender and receiver. C K(M) = fixed length authenticator. 16. Differentiate internal and external error control. Internal error control: In internal error control, an error detecting code also known as frame check sequence or checksum. External error control: In external error control, error detecting codes are appended after encryption. 17. What is the meet in the middle attack? This is the cryptanalytic attack that attempts to find the value in each of the range and domain of the composition of two functions such that the forward mapping of one through the first function is the same as the inverse image of the other through the second function-quite literally meeting in the middle of the composed function. 18. What is the role of compression function in hash function? The hash algorithm involves repeated use of a compression function f, that takes two inputs and produce a n-bit output. At the start of hashing the chaining variable has an initial value that is specified as part of

18 the algorithm. The final value of the chaining variable is the hash value usually b>n; hence the term compression.

Integrated services Digital Network

Integrated services Digital Network Integrated services Digital Network 1 Integrated Services Digital Network Public networks are used for a variety of services Public Switched Telephone Network Private Lines (leased) Packet Switched Data

More information

Security+ Guide to Network Security Fundamentals, Third Edition. Chapter 11 Basic Cryptography

Security+ Guide to Network Security Fundamentals, Third Edition. Chapter 11 Basic Cryptography Security+ Guide to Network Security Fundamentals, Third Edition Chapter 11 Basic Cryptography Objectives Define cryptography Describe hashing List the basic symmetric cryptographic algorithms 2 Objectives

More information

Introduction to Network Security Missouri S&T University CPE 5420 Data Integrity Algorithms

Introduction to Network Security Missouri S&T University CPE 5420 Data Integrity Algorithms Introduction to Network Security Missouri S&T University CPE 5420 Data Integrity Algorithms Egemen K. Çetinkaya Egemen K. Çetinkaya Department of Electrical & Computer Engineering Missouri University of

More information

William Stallings Data and Computer Communications 7 th Edition. Chapter 10 Circuit Switching and Packet Switching

William Stallings Data and Computer Communications 7 th Edition. Chapter 10 Circuit Switching and Packet Switching William Stallings Data and Computer Communications 7 th Edition Chapter 10 Circuit Switching and Packet Switching Switching Networks Long distance transmission is typically done over a network of switched

More information

KALASALINGAM UNIVERSITY

KALASALINGAM UNIVERSITY KALASALINGAM UNIVERSITY (Kalasalingam Academy of Research and Education) DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING CLASS NOTES CRYPTOGRAPHY AND NETWOTK SECURITY (CSE 405) Prepared by M.RAJA AP/CSE

More information

Cryptographic Concepts

Cryptographic Concepts Outline Identify the different types of cryptography Learn about current cryptographic methods Chapter #23: Cryptography Understand how cryptography is applied for security Given a scenario, utilize general

More information

Circuit Switching and Packet Switching

Circuit Switching and Packet Switching Chapter 10: Circuit Switching and Packet Switching CS420/520 Axel Krings Page 1 Switching Networks Long distance transmission is typically done over a network of switched nodes Nodes not concerned with

More information

Security Requirements

Security Requirements Message Authentication and Hash Functions CSCI 454/554 Security Requirements disclosure traffic analysis masquerade content modification sequence modification timing modification source repudiation destination

More information

06/02/ Local & Metropolitan Area Networks. 0. Overview. Terminology ACOE322. Lecture 8 Network Security

06/02/ Local & Metropolitan Area Networks. 0. Overview. Terminology ACOE322. Lecture 8 Network Security 1 Local & Metropolitan Area Networks ACOE322 Lecture 8 Network Security Dr. L. Christofi 1 0. Overview As the knowledge of computer networking and protocols has become more widespread, so the threat of

More information

(2½ hours) Total Marks: 75

(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 information

ST.MOTHER THERESA ENGINEERING COLLEGE

ST.MOTHER THERESA ENGINEERING COLLEGE ST.MOTHER CHETTINAD COLLEGE OF ENGINEERING THERESA & TECHNOLOGY ENGINEERING COLLEGE DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING SUBJECT CODE: CS 2060 SEM/YEAR: VII/IV SUBJECT NAME: HIGH SPEED

More information

CSCE 715: Network Systems Security

CSCE 715: Network Systems Security CSCE 715: Network Systems Security Chin-Tser Huang huangct@cse.sc.edu University of South Carolina Next Topic in Cryptographic Tools Symmetric key encryption Asymmetric key encryption Hash functions and

More information

Spring 2010: CS419 Computer Security

Spring 2010: CS419 Computer Security Spring 2010: CS419 Computer Security MAC, HMAC, Hash functions and DSA Vinod Ganapathy Lecture 6 Message Authentication message authentication is concerned with: protecting the integrity of a message validating

More information

Cryptography (DES+RSA) by Amit Konar Dept. of Math and CS, UMSL

Cryptography (DES+RSA) by Amit Konar Dept. of Math and CS, UMSL Cryptography (DES+RSA) by Amit Konar Dept. of Math and CS, UMSL Transpositional Ciphers-A Review Decryption 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Encryption 1 2 3 4 5 6 7 8 A G O O D F R I E N D I S A T R E

More information

Security. Communication security. System Security

Security. Communication security. System Security Security Communication security security of data channel typical assumption: adversary has access to the physical link over which data is transmitted cryptographic separation is necessary System Security

More information

Sankalchand Patel College of Engineering, Visnagar Department of Computer Engineering & Information Technology. Question Bank

Sankalchand Patel College of Engineering, Visnagar Department of Computer Engineering & Information Technology. Question Bank Sankalchand Patel College of Engineering, Visnagar Department of Computer Engineering & Information Technology Question Bank Subject: Information Security (160702) Class: BE Sem. VI (CE/IT) Unit-1: Conventional

More information

Data and Computer Communications

Data and Computer Communications Data and Computer Communications Chapter 10 Circuit Switching and Packet Switching Eighth Edition by William Stallings Lecture slides by Lawrie Brown Circuit Switching and Packet Switching He got into

More information

Frame Relay. Raj Jain. Professor of Computer and Information Sciences. The Ohio State University

Frame Relay. Raj Jain. Professor of Computer and Information Sciences. The Ohio State University Frame Relay Professor of Computer and Information Sciences Columbus, OH 43210 Jain@ACM.Org http://www.cis.ohio-state.edu/~jain/ 1 Overview What is Frame Relay? Why not leased lines or X.25? Frame formats

More information

L13. Reviews. Rocky K. C. Chang, April 10, 2015

L13. 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 information

Encryption Algorithms Authentication Protocols Message Integrity Protocols Key Distribution Firewalls

Encryption Algorithms Authentication Protocols Message Integrity Protocols Key Distribution Firewalls Security Outline Encryption Algorithms Authentication Protocols Message Integrity Protocols Key Distribution Firewalls Overview Cryptography functions Secret key (e.g., DES) Public key (e.g., RSA) Message

More information

Public Key Cryptography

Public Key Cryptography graphy CSS322: Security and Cryptography Sirindhorn International Institute of Technology Thammasat University Prepared by Steven Gordon on 29 December 2011 CSS322Y11S2L07, Steve/Courses/2011/S2/CSS322/Lectures/rsa.tex,

More information

CSCI 454/554 Computer and Network Security. Topic 5.2 Public Key Cryptography

CSCI 454/554 Computer and Network Security. Topic 5.2 Public Key Cryptography CSCI 454/554 Computer and Network Security Topic 5.2 Public Key Cryptography Outline 1. Introduction 2. RSA 3. Diffie-Hellman Key Exchange 4. Digital Signature Standard 2 Introduction Public Key Cryptography

More information

Encryption. INST 346, Section 0201 April 3, 2018

Encryption. INST 346, Section 0201 April 3, 2018 Encryption INST 346, Section 0201 April 3, 2018 Goals for Today Symmetric Key Encryption Public Key Encryption Certificate Authorities Secure Sockets Layer Simple encryption scheme substitution cipher:

More information

Digests Requirements MAC Hash function Security of Hash and MAC Birthday Attack MD5 SHA RIPEMD Digital Signature Standard Proof of DSS

Digests Requirements MAC Hash function Security of Hash and MAC Birthday Attack MD5 SHA RIPEMD Digital Signature Standard Proof of DSS UNIT III AUTHENTICATION Digests Requirements MAC Hash function Security of Hash and MAC Birthday Attack MD5 SHA RIPEMD Digital Signature Standard Proof of DSS Authentication Requirements Disclosure Release

More information

Outline. CSCI 454/554 Computer and Network Security. Introduction. Topic 5.2 Public Key Cryptography. 1. Introduction 2. RSA

Outline. CSCI 454/554 Computer and Network Security. Introduction. Topic 5.2 Public Key Cryptography. 1. Introduction 2. RSA CSCI 454/554 Computer and Network Security Topic 5.2 Public Key Cryptography 1. Introduction 2. RSA Outline 3. Diffie-Hellman Key Exchange 4. Digital Signature Standard 2 Introduction Public Key Cryptography

More information

How many DES keys, on the average, encrypt a particular plaintext block to a particular ciphertext block?

How many DES keys, on the average, encrypt a particular plaintext block to a particular ciphertext block? Homework 1. Come up with as efficient an encoding as you can to specify a completely general one-to-one mapping between 64-bit input values and 64-bit output values. 2. Token cards display a number that

More information

Outline. Public Key Cryptography. Applications of Public Key Crypto. Applications (Cont d)

Outline. Public Key Cryptography. Applications of Public Key Crypto. Applications (Cont d) Outline AIT 682: Network and Systems Security 1. Introduction 2. RSA 3. Diffie-Hellman Key Exchange 4. Digital Signature Standard Topic 5.2 Public Key Cryptography Instructor: Dr. Kun Sun 2 Public Key

More information

Introduction to Cryptography. Vasil Slavov William Jewell College

Introduction to Cryptography. Vasil Slavov William Jewell College Introduction to Cryptography Vasil Slavov William Jewell College Crypto definitions Cryptography studies how to keep messages secure Cryptanalysis studies how to break ciphertext Cryptology branch of mathematics,

More information

The question paper contains 40 multiple choice questions with four choices and students will have to pick the correct one (each carrying ½ marks.).

The question paper contains 40 multiple choice questions with four choices and students will have to pick the correct one (each carrying ½ marks.). Time: 3hrs BCA III Network security and Cryptography Examination-2016 Model Paper 2 M.M:50 The question paper contains 40 multiple choice questions with four choices and students will have to pick the

More information

CRYPTOLOGY KEY MANAGEMENT CRYPTOGRAPHY CRYPTANALYSIS. Cryptanalytic. Brute-Force. Ciphertext-only Known-plaintext Chosen-plaintext Chosen-ciphertext

CRYPTOLOGY KEY MANAGEMENT CRYPTOGRAPHY CRYPTANALYSIS. Cryptanalytic. Brute-Force. Ciphertext-only Known-plaintext Chosen-plaintext Chosen-ciphertext CRYPTOLOGY CRYPTOGRAPHY KEY MANAGEMENT CRYPTANALYSIS Cryptanalytic Brute-Force Ciphertext-only Known-plaintext Chosen-plaintext Chosen-ciphertext 58 Types of Cryptographic Private key (Symmetric) Public

More information

Cryptography and Network Security

Cryptography and Network Security Cryptography and Network Security Third Edition by William Stallings Lecture slides by Lawrie Brown Chapter 15 Electronic Mail Security Despite the refusal of VADM Poindexter and LtCol North to appear,

More information

Computer Security: Principles and Practice

Computer Security: Principles and Practice Computer Security: Principles and Practice Chapter 2 Cryptographic Tools First Edition by William Stallings and Lawrie Brown Lecture slides by Lawrie Brown Cryptographic Tools cryptographic algorithms

More information

Cryptographic Hash Functions

Cryptographic Hash Functions Cryptographic Hash Functions Cryptographic Hash Functions A cryptographic hash function takes a message of arbitrary length and creates a message digest of fixed length. Iterated Hash Function A (compression)

More information

Cryptography MIS

Cryptography MIS Cryptography MIS-5903 http://community.mis.temple.edu/mis5903sec011s17/ Cryptography History Substitution Monoalphabetic Polyalphabetic (uses multiple alphabets) uses Vigenere Table Scytale cipher (message

More information

IEEE Std and IEEE Std 1363a Ashley Butterworth Apple Inc.

IEEE Std and IEEE Std 1363a Ashley Butterworth Apple Inc. apple IEEE Std 1363-2000 and IEEE Std 1363a-2004 Ashley Butterworth Apple Inc. The Titles IEEE Std 1363-2000 - IEEE Standard Specifications for Public-Key Cryptography IEED Std 1363a-2004 - IEEE Standard

More information

Distributed Systems. 26. Cryptographic Systems: An Introduction. Paul Krzyzanowski. Rutgers University. Fall 2015

Distributed Systems. 26. Cryptographic Systems: An Introduction. Paul Krzyzanowski. Rutgers University. Fall 2015 Distributed Systems 26. Cryptographic Systems: An Introduction Paul Krzyzanowski Rutgers University Fall 2015 1 Cryptography Security Cryptography may be a component of a secure system Adding cryptography

More information

COMP4109 : Applied Cryptography

COMP4109 : Applied Cryptography COMP4109 : Applied Cryptography Fall 2013 M. Jason Hinek Carleton University Applied Cryptography Day 2 information security cryptographic primitives unkeyed primitives NSA... one-way functions hash functions

More information

Public Key Algorithms

Public Key Algorithms Public Key Algorithms 1 Public Key Algorithms It is necessary to know some number theory to really understand how and why public key algorithms work Most of the public key algorithms are based on modular

More information

CRYPTOGRAPHY AND NETWROK SECURITY-QUESTION BANK

CRYPTOGRAPHY AND NETWROK SECURITY-QUESTION BANK CRYPTOGRAPHY AND NETWROK SECURITY-QUESTION BANK UNIT-1 1. Answer the following: a. What is Non-repudiation b. Distinguish between stream and block ciphers c. List out the problems of one time pad d. Define

More information

Lecture (04 & 05) Packet switching & Frame Relay techniques Dr. Ahmed ElShafee

Lecture (04 & 05) Packet switching & Frame Relay techniques Dr. Ahmed ElShafee Agenda Lecture (04 & 05) Packet switching & Frame Relay techniques Dr. Ahmed ElShafee Packet switching technique Packet switching protocol layers (X.25) Frame Relay ١ Dr. Ahmed ElShafee, ACU Fall 2011,

More information

Lecture (04 & 05) Packet switching & Frame Relay techniques

Lecture (04 & 05) Packet switching & Frame Relay techniques Lecture (04 & 05) Packet switching & Frame Relay techniques Dr. Ahmed ElShafee ١ Dr. Ahmed ElShafee, ACU Fall 2011, Networks I Agenda Packet switching technique Packet switching protocol layers (X.25)

More information

Module 13 Network Security. Version 1 ECE, IIT Kharagpur

Module 13 Network Security. Version 1 ECE, IIT Kharagpur Module 13 Network Security Lesson 40 Network Security 13.1.1 INTRODUCTION Network Security assumes a great importance in the current age. In this chapter we shall look at some of the security measures

More information

LECTURE NOTES ON PUBLIC- KEY CRYPTOGRAPHY. (One-Way Functions and ElGamal System)

LECTURE NOTES ON PUBLIC- KEY CRYPTOGRAPHY. (One-Way Functions and ElGamal System) Department of Software The University of Babylon LECTURE NOTES ON PUBLIC- KEY CRYPTOGRAPHY (One-Way Functions and ElGamal System) By College of Information Technology, University of Babylon, Iraq Samaher@itnet.uobabylon.edu.iq

More information

Winter 2011 Josh Benaloh Brian LaMacchia

Winter 2011 Josh Benaloh Brian LaMacchia Winter 2011 Josh Benaloh Brian LaMacchia Symmetric Cryptography January 20, 2011 Practical Aspects of Modern Cryptography 2 Agenda Symmetric key ciphers Stream ciphers Block ciphers Cryptographic hash

More information

Cryptography and Network Security Chapter 12. Message Authentication. Message Security Requirements. Public Key Message Encryption

Cryptography and Network Security Chapter 12. Message Authentication. Message Security Requirements. Public Key Message Encryption Cryptography and Network Security Chapter 12 Fifth Edition by William Stallings Lecture slides by Lawrie Brown Chapter 12 Message Authentication Codes At cats' green on the Sunday he took the message from

More information

Chapter 9. Public Key Cryptography, RSA And Key Management

Chapter 9. Public Key Cryptography, RSA And Key Management Chapter 9 Public Key Cryptography, RSA And Key Management RSA by Rivest, Shamir & Adleman of MIT in 1977 The most widely used public-key cryptosystem is RSA. The difficulty of attacking RSA is based on

More information

14. Internet Security (J. Kurose)

14. Internet Security (J. Kurose) 14. Internet Security (J. Kurose) 1 Network security Foundations: what is security? cryptography authentication message integrity key distribution and certification Security in practice: application layer:

More information

Kurose & Ross, Chapters (5 th ed.)

Kurose & 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 information

Cryptography and Network Security

Cryptography and Network Security Cryptography and Network Security Spring 2012 http://users.abo.fi/ipetre/crypto/ Lecture 14: Folklore, Course summary, Exam requirements Ion Petre Department of IT, Åbo Akademi University 1 Folklore on

More information

Security: Cryptography

Security: Cryptography Security: Cryptography Computer Science and Engineering College of Engineering The Ohio State University Lecture 38 Some High-Level Goals Confidentiality Non-authorized users have limited access Integrity

More information

Princess Nora Bint Abdulrahman University College of computer and information sciences Networks department Networks Security (NET 536)

Princess Nora Bint Abdulrahman University College of computer and information sciences Networks department Networks Security (NET 536) Princess Nora Bint Abdulrahman University College of computer and information sciences Networks department Networks Security (NET 536) Prepared by Dr. Samia Chelloug E-mail: samia_chelloug@yahoo.fr Content

More information

Introduction. CSE 5351: Introduction to cryptography Reading assignment: Chapter 1 of Katz & Lindell

Introduction. CSE 5351: Introduction to cryptography Reading assignment: Chapter 1 of Katz & Lindell Introduction CSE 5351: Introduction to cryptography Reading assignment: Chapter 1 of Katz & Lindell 1 Cryptography Merriam-Webster Online Dictionary: 1. secret writing 2. the enciphering and deciphering

More information

CSE 3461/5461: Introduction to Computer Networking and Internet Technologies. Network Security. Presentation L

CSE 3461/5461: Introduction to Computer Networking and Internet Technologies. Network Security. Presentation L CS 3461/5461: Introduction to Computer Networking and Internet Technologies Network Security Study: 21.1 21.5 Kannan Srinivasan 11-27-2012 Security Attacks, Services and Mechanisms Security Attack: Any

More information

APNIC elearning: Cryptography Basics

APNIC elearning: Cryptography Basics APNIC elearning: Cryptography Basics 27 MAY 2015 03:00 PM AEST Brisbane (UTC+10) Issue Date: Revision: Introduction Presenter Sheryl Hermoso Training Officer sheryl@apnic.net Specialties: Network Security

More information

Frame Relay. Raj Jain. Professor of Computer and Information Sciences. The Ohio State University. Columbus, OH 43210

Frame Relay. Raj Jain. Professor of Computer and Information Sciences. The Ohio State University. Columbus, OH 43210 Frame Relay Professor of Computer and Information Sciences Columbus, OH 43210 These slides are available at http://www.cis.ohio-state.edu/~jain/cis777-99/ 1 Overview What is Frame Relay? Why not leased

More information

Cryptography Functions

Cryptography Functions Cryptography Functions Lecture 3 1/29/2013 References: Chapter 2-3 Network Security: Private Communication in a Public World, Kaufman, Perlman, Speciner Types of Cryptographic Functions Secret (Symmetric)

More information

Lecture 30. Cryptography. Symmetric Key Cryptography. Key Exchange. Advanced Encryption Standard (AES) DES. Security April 11, 2005

Lecture 30. Cryptography. Symmetric Key Cryptography. Key Exchange. Advanced Encryption Standard (AES) DES. Security April 11, 2005 Lecture 30 Security April 11, 2005 Cryptography K A ciphertext Figure 7.3 goes here K B symmetric-key crypto: sender, receiver keys identical public-key crypto: encrypt key public, decrypt key secret Symmetric

More information

PROTECTING CONVERSATIONS

PROTECTING CONVERSATIONS PROTECTING CONVERSATIONS Basics of Encrypted Network Communications Naïve Conversations Captured messages could be read by anyone Cannot be sure who sent the message you are reading Basic Definitions Authentication

More information

PESIT Bangalore South Campus Hosur road, 1km before Electronic City, Bengaluru -100 Department of Computer Science and Engineering

PESIT Bangalore South Campus Hosur road, 1km before Electronic City, Bengaluru -100 Department of Computer Science and Engineering INTERNAL ASSESSMENT TEST 2 Date : 01 04 201 Marks : 0 Subject & Code :Computer Networks 2(10CS64) Class : VI CSE B Name of faculty : Surbhi Agrawal Time : 8:30 to 10:00a.m Note: wer ALL Questions 1 a B

More information

Secure Multiparty Computation

Secure Multiparty Computation CS573 Data Privacy and Security Secure Multiparty Computation Problem and security definitions Li Xiong Outline Cryptographic primitives Symmetric Encryption Public Key Encryption Secure Multiparty Computation

More information

1.264 Lecture 28. Cryptography: Asymmetric keys

1.264 Lecture 28. Cryptography: Asymmetric keys 1.264 Lecture 28 Cryptography: Asymmetric keys Next class: Anderson chapters 20. Exercise due before class (Reading doesn t cover same topics as lecture) 1 Asymmetric or public key encryption Receiver

More information

Unit III. Chapter 1: Message Authentication and Hash Functions. Overview:

Unit III. Chapter 1: Message Authentication and Hash Functions. Overview: Unit III Chapter 1: Message Authentication and Hash Functions Overview: Message authentication is a mechanism or service used to verify the integrity of a message. Message authentication assures that data

More information

Chapter 6. New HASH Function. 6.1 Message Authentication. Message authentication is a mechanism or service used for verifying

Chapter 6. New HASH Function. 6.1 Message Authentication. Message authentication is a mechanism or service used for verifying Chapter 6 New HASH Function 6.1 Message Authentication Message authentication is a mechanism or service used for verifying the integrity of a message. Message authentication assures that the data received

More information

ח'/סיון/תשע "א. RSA: getting ready. Public Key Cryptography. Public key cryptography. Public key encryption algorithms

ח'/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 information

Lecture 1 Applied Cryptography (Part 1)

Lecture 1 Applied Cryptography (Part 1) Lecture 1 Applied Cryptography (Part 1) Patrick P. C. Lee Tsinghua Summer Course 2010 1-1 Roadmap Introduction to Security Introduction to Cryptography Symmetric key cryptography Hash and message authentication

More information

CSC 474/574 Information Systems Security

CSC 474/574 Information Systems Security CSC 474/574 Information Systems Security Topic 2.5 Public Key Algorithms CSC 474/574 Dr. Peng Ning 1 Public Key Algorithms Public key algorithms covered in this class RSA: encryption and digital signature

More information

Security in Distributed Systems. Network Security

Security in Distributed Systems. Network Security Security in Distributed Systems Introduction Cryptography Authentication Key exchange Readings: Tannenbaum, chapter 8 Ross/Kurose, Ch 7 (available online) Computer Science Lecture 22, page 1 Network Security

More information

S. Erfani, ECE Dept., University of Windsor Network Security

S. Erfani, ECE Dept., University of Windsor Network Security 4.11 Data Integrity and Authentication It was mentioned earlier in this chapter that integrity and protection security services are needed to protect against active attacks, such as falsification of data

More information

The University of Sydney AUSTRALIA. Advanced Communication Networks

The University of Sydney AUSTRALIA. Advanced Communication Networks The University of Sydney AUSTRALIA School of Electrical and Information Engineering Advanced Communication Networks Chapter 5 ISDN Data Link Layer Based on chapter 8 of Stallings ISDN-4e book Abbas Jamalipour

More information

Other Topics in Cryptography. Truong Tuan Anh

Other Topics in Cryptography. Truong Tuan Anh Other Topics in Cryptography Truong Tuan Anh 2 Outline Public-key cryptosystem Cryptographic hash functions Signature schemes Public-Key Cryptography Truong Tuan Anh CSE-HCMUT 4 Outline Public-key cryptosystem

More information

Encryption I. An Introduction

Encryption I. An Introduction Encryption I An Introduction Reading List ADO and SQL Server Security A Simple Guide to Cryptography Protecting Private Data with the Cryptography Namespaces Using MD5 to Encrypt Passwords in a Database

More information

Public Key Algorithms

Public Key Algorithms CSE597B: Special Topics in Network and Systems Security Public Key Cryptography Instructor: Sencun Zhu The Pennsylvania State University Public Key Algorithms Public key algorithms RSA: encryption and

More information

Classical Cryptography. Thierry Sans

Classical Cryptography. Thierry Sans Classical Cryptography Thierry Sans Example and definitions of a cryptosystem Caesar Cipher - the oldest cryptosystem A shift cipher attributed to Julius Caesar (100-44 BC) MEET ME AFTER THE TOGA PARTY

More information

Public Key Cryptography and RSA

Public Key Cryptography and RSA Public Key Cryptography and RSA Major topics Principles of public key cryptosystems The RSA algorithm The Security of RSA Motivations A public key system is asymmetric, there does not have to be an exchange

More information

Security: Focus of Control. Authentication

Security: 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 information

Lecture 9a: Secure Sockets Layer (SSL) March, 2004

Lecture 9a: Secure Sockets Layer (SSL) March, 2004 Internet and Intranet Protocols and Applications Lecture 9a: Secure Sockets Layer (SSL) March, 2004 Arthur Goldberg Computer Science Department New York University artg@cs.nyu.edu Security Achieved by

More information

Lecture 5. Cryptographic Hash Functions. Read: Chapter 5 in KPS

Lecture 5. Cryptographic Hash Functions. Read: Chapter 5 in KPS Lecture 5 Cryptographic Hash Functions Read: Chapter 5 in KPS 1 Purpose CHF one of the most important tools in modern cryptography and security CHF-s are used for many authentication, integrity, digital

More information

Chapter 8 Security. Computer Networking: A Top Down Approach. 6 th edition Jim Kurose, Keith Ross Addison-Wesley March 2012

Chapter 8 Security. Computer Networking: A Top Down Approach. 6 th edition Jim Kurose, Keith Ross Addison-Wesley March 2012 Chapter 8 Security A note on the use of these ppt slides: We re making these slides freely available to all (faculty, students, readers). They re in PowerPoint form so you see the animations; and can add,

More information

Ref:

Ref: Cryptography & digital signature Dec. 2013 Ref: http://cis.poly.edu/~ross/ 2 Cryptography Overview Symmetric Key Cryptography Public Key Cryptography Message integrity and digital signatures References:

More information

Computer Networking. What is network security? Chapter 7: Network security. Symmetric key cryptography. The language of cryptography

Computer Networking. What is network security? Chapter 7: Network security. Symmetric key cryptography. The language of cryptography Chapter 7: Network security 15-441 Computer Networking Network Security: Cryptography, Authentication, Integrity Foundations: what is security? cryptography authentication message integrity key distribution

More information

Channel Coding and Cryptography Part II: Introduction to Cryptography

Channel Coding and Cryptography Part II: Introduction to Cryptography Channel Coding and Cryptography Part II: Introduction to Cryptography Prof. Dr.-Ing. habil. Andreas Ahrens Communications Signal Processing Group, University of Technology, Business and Design Email: andreas.ahrens@hs-wismar.de

More information

Computer Security. 08. Cryptography Part II. Paul Krzyzanowski. Rutgers University. Spring 2018

Computer Security. 08. Cryptography Part II. Paul Krzyzanowski. Rutgers University. Spring 2018 Computer Security 08. Cryptography Part II Paul Krzyzanowski Rutgers University Spring 2018 March 23, 2018 CS 419 2018 Paul Krzyzanowski 1 Block ciphers Block ciphers encrypt a block of plaintext at a

More information

Computer Security. 10r. Recitation assignment & concept review. Paul Krzyzanowski. Rutgers University. Spring 2018

Computer Security. 10r. Recitation assignment & concept review. Paul Krzyzanowski. Rutgers University. Spring 2018 Computer Security 10r. Recitation assignment & concept review Paul Krzyzanowski Rutgers University Spring 2018 April 3, 2018 CS 419 2018 Paul Krzyzanowski 1 1. What is a necessary condition for perfect

More information

IPSec. Slides by Vitaly Shmatikov UT Austin. slide 1

IPSec. Slides by Vitaly Shmatikov UT Austin. slide 1 IPSec Slides by Vitaly Shmatikov UT Austin slide 1 TCP/IP Example slide 2 IP Security Issues Eavesdropping Modification of packets in transit Identity spoofing (forged source IP addresses) Denial of service

More information

Key Exchange. References: Applied Cryptography, Bruce Schneier Cryptography and Network Securiy, Willian Stallings

Key Exchange. References: Applied Cryptography, Bruce Schneier Cryptography and Network Securiy, Willian Stallings Key Exchange References: Applied Cryptography, Bruce Schneier Cryptography and Network Securiy, Willian Stallings Outlines Primitives Root Discrete Logarithm Diffie-Hellman ElGamal Shamir s Three Pass

More information

Computer Security 3/23/18

Computer Security 3/23/18 s s encrypt a block of plaintext at a time and produce ciphertext Computer Security 08. Cryptography Part II Paul Krzyzanowski DES & AES are two popular block ciphers DES: 64 bit blocks AES: 128 bit blocks

More information

Computer Networks. Wenzhong Li. Nanjing University

Computer 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 information

Overview. SSL Cryptography Overview CHAPTER 1

Overview. SSL Cryptography Overview CHAPTER 1 CHAPTER 1 Secure Sockets Layer (SSL) is an application-level protocol that provides encryption technology for the Internet. SSL ensures the secure transmission of data between a client and a server through

More information

TopSec Product Family Voice encryption at the highest security level

TopSec Product Family Voice encryption at the highest security level Secure Communications Product Brochure 01.01 TopSec Product Family Voice encryption at the highest security level TopSec Product Family At a glance The TopSec product family provides end-to-end voice encryption

More information

CS Computer Networks 1: Authentication

CS Computer Networks 1: Authentication CS 3251- Computer Networks 1: Authentication Professor Patrick Traynor 4/14/11 Lecture 25 Announcements Homework 3 is due next class. Submit via T-Square or in person. Project 3 has been graded. Scores

More information

Some Stuff About Crypto

Some Stuff About Crypto Some Stuff About Crypto Adrian Frith Laboratory of Foundational Aspects of Computer Science Department of Mathematics and Applied Mathematics University of Cape Town This work is licensed under a Creative

More information

Lecture 6: Overview of Public-Key Cryptography and RSA

Lecture 6: Overview of Public-Key Cryptography and RSA 1 Lecture 6: Overview of Public-Key Cryptography and RSA Yuan Xue In this lecture, we give an overview to the public-key cryptography, which is also referred to as asymmetric cryptography. We will first

More information

Lecture III : Communication Security Mechanisms

Lecture III : Communication Security Mechanisms Lecture III : Communication Security Mechanisms Internet Security: Principles & Practices John K. Zao, PhD (Harvard) SMIEEE Computer Science Department, National Chiao Tung University 2 X.800 : Security

More information

Tuesday, January 17, 17. Crypto - mini lecture 1

Tuesday, January 17, 17. Crypto - mini lecture 1 Crypto - mini lecture 1 Cryptography Symmetric key cryptography (secret key crypto): sender and receiver keys identical Asymmetric key cryptography (public key crypto): encryption key public, decryption

More information

Cryptography Basics. IT443 Network Security Administration Slides courtesy of Bo Sheng

Cryptography Basics. IT443 Network Security Administration Slides courtesy of Bo Sheng Cryptography Basics IT443 Network Security Administration Slides courtesy of Bo Sheng 1 Outline Basic concepts in cryptography systems Secret key cryptography Public key cryptography Hash functions 2 Encryption/Decryption

More information

Outline. Data Encryption Standard. Symmetric-Key Algorithms. Lecture 4

Outline. Data Encryption Standard. Symmetric-Key Algorithms. Lecture 4 EEC 693/793 Special Topics in Electrical Engineering Secure and Dependable Computing Lecture 4 Department of Electrical and Computer Engineering Cleveland State University wenbing@ieee.org Outline Review

More information

Introduction to Cryptography and Security Mechanisms: Unit 5. Public-Key Encryption

Introduction to Cryptography and Security Mechanisms: Unit 5. Public-Key Encryption Introduction to Cryptography and Security Mechanisms: Unit 5 Public-Key Encryption Learning Outcomes Explain the basic principles behind public-key cryptography Recognise the fundamental problems that

More information

9/30/2016. Cryptography Basics. Outline. Encryption/Decryption. Cryptanalysis. Caesar Cipher. Mono-Alphabetic Ciphers

9/30/2016. Cryptography Basics. Outline. Encryption/Decryption. Cryptanalysis. Caesar Cipher. Mono-Alphabetic Ciphers Cryptography Basics IT443 Network Security Administration Slides courtesy of Bo Sheng Basic concepts in cryptography systems Secret cryptography Public cryptography 1 2 Encryption/Decryption Cryptanalysis

More information

Security: Focus of Control

Security: 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 information

Cryptography and Network Security. Sixth Edition by William Stallings

Cryptography and Network Security. Sixth Edition by William Stallings Cryptography and Network Security Sixth Edition by William Stallings Chapter 9 Public Key Cryptography and RSA Misconceptions Concerning Public-Key Encryption Public-key encryption is more secure from

More information