BZUPAGES.COM Cryptography Cryptography is the technique of converting a message into unintelligible or non-understandable form such that even if some unauthorized.

Slides:



Advertisements
Similar presentations
CLASSICAL ENCRYPTION TECHNIQUES
Advertisements

Chapter 10 Encryption: A Matter of Trust. Awad –Electronic Commerce 1/e © 2002 Prentice Hall 2 OBJECTIVES What is Encryption? Basic Cryptographic Algorithm.
Public Key Infrastructure and Applications
Chapter 11: Cryptography
Computer Science CSC 474By Dr. Peng Ning1 CSC 474 Information Systems Security Topic 2.1 Introduction to Cryptography.
Crytography Chapter 8.
Principles of Information Security, 2nd edition1 Cryptography.
Lesson Title: Introduction to Cryptography Dale R. Thompson Computer Science and Computer Engineering Dept. University of Arkansas
Cryptography Basic (cont)
BY MUKTADIUR RAHMAN MAY 06, 2010 INTERODUCTION TO CRYPTOGRAPHY.
Cryptographic Technologies
Overview of Cryptography and Its Applications Dr. Monther Aldwairi New York Institute of Technology- Amman Campus INCS741: Cryptography.
Chapter 8.  Cryptography is the science of keeping information secure in terms of confidentiality and integrity.  Cryptography is also referred to as.
Encryption. Introduction Computer security is the prevention of or protection against –access to information by unauthorized recipients –intentional but.
Encryption is a way to transform a message so that only the sender and recipient can read, see or understand it. The mechanism is based on the use of.
1 Fluency with Information Technology Lawrence Snyder Chapter 17 Privacy & Digital Security Encryption.
1 Cryptography Cryptography is a collection of mathematical techniques to ensure confidentiality of information Cryptography is a collection of mathematical.
1 Cryptography Basics. 2 Cryptography Basic terminologies Symmetric key encryption Asymmetric key encryption Public Key Infrastructure Digital Certificates.
A Cryptography Education Tool Anna Yu Department of Computer Science College of Engineering North Carolina A&T State University June 18, 2009.
Chi-Cheng Lin, Winona State University CS 313 Introduction to Computer Networking & Telecommunication Network Security (A Very Brief Introduction)
Chapter 14 Encryption: A Matter Of Trust. Awad –Electronic Commerce 2/e © 2004 Pearson Prentice Hall 2 OBJECTIVES What is Encryption? Basic Cryptographic.
Lecture 19 Page 1 CS 111 Online Symmetric Cryptosystems C = E(K,P) P = D(K,C) E() and D() are not necessarily the same operations.
1 Lesson Internet Organization network Fire wall.
© 2006 Cisco Systems, Inc. All rights reserved. Network Security 2 Module 3: VPN and Encryption Technology.
Network Security. Security Threats 8Intercept 8Interrupt 8Modification 8Fabrication.
Chapter 2 – Elementary Cryptography  Concepts of encryption  Cryptanalysis  Symmetric (secret key) Encryption (DES & AES)(DES & AES)  Asymmetric (public.
Security+ Guide to Network Security Fundamentals, Third Edition Chapter 11 Basic Cryptography.
Chapter 8: Scrambling Through Cryptography Security+ Guide to Network Security Fundamentals Second Edition.
Information Systems Security
Dr. L. Christofi1 Local & Metropolitan Area Networks ACOE322 Lecture 8 Network Security.
Cryptography, Authentication and Digital Signatures
Review of basic cryptographically algorithm Asymmetric encoding (Private and Public Keys), Hash Function, Digital Signatures and Certification.
Chapter 17 Security. Information Systems Cryptography Key Exchange Protocols Password Combinatorics Other Security Issues 12-2.
Module 3 – Cryptography Cryptography basics Ciphers Symmetric Key Algorithms Public Key Algorithms Message Digests Digital Signatures.
Internet Security. Four Issues of Internet Security Authenticity: Is the sender of a message who they claim to be? Privacy: Are the contents of a message.
Chapter 16 Security Introduction to CS 1 st Semester, 2012 Sanghyun Park.
Encryption.
Cryptography Lynn Ackler Southern Oregon University.
Elementary Cryptography  Concepts of encryption  Symmetric (secret key) Encryption (DES & AES)(DES & AES)  Asymmetric (public key) Encryption (RSA)(RSA)
Internet-security.ppt-1 ( ) 2000 © Maximilian Riegel Maximilian Riegel Kommunikationsnetz Franken e.V. Internet Security Putting together the.
11-Basic Cryptography Dr. John P. Abraham Professor UTPA.
Symmetric Cryptography, Asymmetric Cryptography, and Digital Signatures.
What is Digital Signature Building confidentiality and trust into networked transactions. Kishankant Yadav
CRYPTOGRAPHY. TOPICS OF SEMINAR Introduction & Related Terms Categories and Aspects of cryptography Model of Network Security Encryption Techniques Public.
Overview of Cryptography & Its Applications
Security fundamentals Topic 4 Encryption. Agenda Using encryption Cryptography Symmetric encryption Hash functions Public key encryption Applying cryptography.
Encryption Basics Module 7 Section 2. History of Encryption Secret - NSA National Security Agency –has powerful computers - break codes –monitors all.
Electronic Commerce School of Library and Information Science PGP and cryptography I. What is encryption? Cryptographic systems II. What is PGP? How does.
INFORMATION SECURITY MANAGEMENT P ROTECTION M ECHANISMS - C RYPTOGRAPHY.
DATA & COMPUTER SECURITY (CSNB414) MODULE 3 MODERN SYMMETRIC ENCRYPTION.
Multimedia Security. “Everything” is digital these days - a copy of a digital media element is identical to the original. How can an owner protect their.
CSI-09 COMMUNICATION TECHNOLOGY SECURITY MECHANISMS IN A NETWORK AUTHOR - V. V. SUBRAHMANYAM.
Network Security Celia Li Computer Science and Engineering York University.
INFORMATION SECURITY MANAGEMENT P ROTECTION M ECHANISMS - C RYPTOGRAPHY.
INCS 741: Cryptography Overview and Basic Concepts.
M2 Encryption techniques Gladys Nzita-Mak. What is encryption? Encryption is the method of having information such as text being converted into a format.
Computer Security By Rubel Biswas. Introduction History Terms & Definitions Symmetric and Asymmetric Attacks on Cryptosystems Outline.
1 Original Message Scrambled Message Public Key receiver Internet Scrambled+Signed Message Original Message Private Key receiver The Process of Sending.
Department of Computer Science Chapter 5 Introduction to Cryptography Semester 1.
CRYPTOGRAPHY Cryptography is art or science of transforming intelligible message to unintelligible and again transforming that message back to the original.
ISA 400 Management of Information Security
Cryptography and Security Technologies
Chapter-2 Classical Encryption Techniques.
Cryptography.
Unit 2: Cryptography & Cryptographic Algorithm
10/7/2019 Created by Omeed Mustafa 1 st Semester M.Sc (Computer Science department) Cyber-Security.
Presentation transcript:

BZUPAGES.COM Cryptography Cryptography is the technique of converting a message into unintelligible or non-understandable form such that even if some unauthorized or unwanted person intercepts the message he/she would still not be able to make any sense out of it.

BZUPAGES.COM Techniques of Cryptography Substitution Techniques used for cryptography Substitution In substitution we replace each letter in the message with another to make the message non-understandable. For example, each letter “a” in the message can be replaced with letter “d” and letter “b” with letter “e” and so on. Transposition Transposition It is based on scrambling the characters in a message. A transposition system may first write a message into a table row by row then the message can be read and rewritten column by column to make it scrambled

BZUPAGES.COM Transposition IWILL NOTCO METDA Y.TEL LCR INMYLWOE.CITTTRLCDELOAL

BZUPAGES.COM Cryptography is a collection of mathematical techniques used to ensure confidentiality of information. Encryption The process of scrambling a message with the help of a key is called Encryption. Decryption The process of unscrambling a message using an appropriate key is called decryption. Keys are numbers or characters that are randomly generated with the help of some cryptographic algorithm. Pretty Good Privacy (PGP) is the name of a popular cryptographic system which is available for general public use.

BZUPAGES.COM Plain Text Encryption Decryption Cipher Text Key Encryption Algorithm

BZUPAGES.COM Types of Cryptography Symmetric Cryptography In symmetric cryptography same keys are used for encryption and decryption. Asymmetric or Public Key Cryptography In this type a pair of public and private keys is used for encryption and decryption.

BZUPAGES.COM Original Text Cipher Text Recipients public Key Original Text Encryption Algorithm Decryption Algorithm Recipients Secret Key

BZUPAGES.COM Digital/electronic signature An electronic signature means any letters, numbers, symbols, images, characters or any combination thereof in electronic form applied to an electronic document which can ensure authenticity, integrity and non-repudiation. It uses public key cryptography. Authenticity means that the message is from a particular source/individual. Integrity means that the message has not been altered during transmission. Non-repudiation means that the execution of the digital signatures cannot be denied by the one who is alleged to be the executor of those signatures

BZUPAGES.COM Digital certificates These are the certificates in electronic form which establish whether or not a public key belongs to the purported owner. A digital certificate at least comprises a public key, certification information (name, ID etc.) and electronic signatures of a certification authority. Digital certificates are prepared according to a generally accepted format called X.509 standard format.

BZUPAGES.COM SYMMETRIC KEY ALGORITHMS Cryptographic algorithms are measured in terms of key length. Following is the list of some popular symmetric key algorithms: DES (Data Encryption Standard) – 56 bits IDEA (International Data Encryption Algorithm (IDEA) – 128 bits RC2 – (block cipher) bits RC4 (stream cipher) – bits Rinjdael – bits

Attacks on Symmetric Key Algorithms Following attacks have been reported on symmetric key algorithms: Key Search Attacks Cryptanalysis System-based Attacks

Key Search (Brute Force) Attacks In this type of attack an attempt is made by the attacker to decrypt the message with every possible key. Thus, the greater the key length, the more difficult it is to identify the key.

Cryptanalysis Encryption algorithms can be defeated by using a combination of sophisticated mathematics and computing power so that many encrypted messages can be deciphered without knowing the key. Such type of an attack is called cryptanalysis.

System-Based Attacks In it the attack is made on the cryptographic system that uses the cryptographic algorithm without actually attacking the algorithm itself.

Public Key Algorithms Following is the list some popular public key algorithms: DSS – Digital Signature Standard based on DSA (Digital Standard Algorithm) – key length is between bits RSA Elliptic Curves

Attacks on Public Key Algorithms Key Search Attacks Analytical Attacks

Key Search Attacks The public key and its corresponding private key are linked with each other with the help of a large composite number. These attacks attempt to derive the private key from its corresponding public key using that number. According to an estimate 1024 bit RSA public key may be factored due to fast computers by Note that both symmetric and asymmetric algorithms are based on different techniques. In case of asymmetric algorithms the increase in key length does not much increase the difficulty level for the attacker as compared to symmetric algorithms. Thus, a 128-bit RC2 symmetric key may prove to be much stronger than a 1024 bit RSA asymmetric public key.

Analytical Attacks Such attacks use some fundamental flaw in the mathematical problem on which the encryption system itself is based so as to break the encryption. Quantum computing is the branch of computer science that deals with the development of cryptographic algorithms. It can also be used to find flaws in the cryptographic system/algorithms and to launch attacks.