Introduction to Cryptography and Secure Communications  What is cryptography?  Encryption  Decryption.

Slides:

Advertisements

Similar presentations

Using Cryptography to Secure Information. Overview Introduction to Cryptography Using Symmetric Encryption Using Hash Functions Using Public Key Encryption.

Advertisements

Computer Science 101 Data Encryption And Computer Networks.

Cryptology Terminology and Early History. Cryptology Terms Cryptology –The science of concealing the meaning of messages and the discovery of the meaning.

Cryptology  Terminology  plaintext - text that is not encrypted.  ciphertext - the output of the encryption process.  key - the information required.

CS 555Topic 11 Cryptography CS 555 Topic 1: Overview of the Course & Introduction to Encryption.

Creating Secret Messages. 2 Why do we need to keep things secret? Historically, secret messages were used in wars and battles For example, the Enigma.

Introduction to Cryptography and Security Mechanisms Dr Keith Martin McCrea

CS426Fall 2010/Lecture 21 Computer Security CS 426 Lecture 2 Cryptography: Terminology & Classic Ciphers.

Presentation Layer Network Format Local Format Information Transformation “few standards, but a lot of ideas”

Encryption. Introduction Computer security is the prevention of or protection against –access to information by unauthorized recipients –intentional but.

1 Introduction to Codes, Ciphers, and Cryptography Michael A. Karls Ball State University.

Section 3.6: An Introduction to Cryptography

Polyalphabetic Substitution Ciphers. First Steps Towards Complexity  If one alphabet is good, then two alphabets must be better!  By doubling the number.

Classical Monoalphabetic Ciphers Day 2. Keyword cipher Select a keyword, if the keyword has any repeated letters, drop all but the first occurrence. Write.

A Technical Seminar Presentation CLASSICAL CRYPTOGRAPHY

Introduction to Information Security Chapter II : Classical Ciphers.

Go to READ the DIRECTIONS Try Path 1 and Path 2

Chapter 2 – Elementary Cryptography  Concepts of encryption  Cryptanalysis  Symmetric (secret key) Encryption (DES & AES)(DES & AES)  Asymmetric (public.

a connection between language and mathematics

Cryptology By Greg Buss Pat Shields Barry Burke. What is Cryptology? Cryptology is the study of “secret writing.” Modern cryptology combines the studies.

I NTRODUCTION TO C RYPTOLOGY Cryptoanalysts, Encryption, and Decryption.

Day 18. Concepts Plaintext: the original message Ciphertext: the transformed message Encryption: transformation of plaintext into ciphertext Decryption:

Network Security Lecture 12 Presented by: Dr. Munam Ali Shah.

Chapter 17 Security. Information Systems Cryptography Key Exchange Protocols Password Combinatorics Other Security Issues 12-2.

Section 2.1: Shift Ciphers and Modular Arithmetic Practice HW from Barr Textbook (not to hand in) p.66 # 1, 2, 3-6, 9-12, 13, 15.

Abstract: Cryptology is a combination of the processes of keeping a message secret (cryptography) and trying to break the secrecy of that message (cryptoanalysis).

Elementary Cryptography  Concepts of encryption  Symmetric (secret key) Encryption (DES & AES)(DES & AES)  Asymmetric (public key) Encryption (RSA)(RSA)

Computer Security Cryptography. Cryptography Now and Before  In the past – mainly used for confidentiality  Today –Still used for confidentiality –Data.

Encryption CS110: Computer Science and the Internet.

K. Salah1 Cryptography Module I. K. Salah2 Cryptographic Protocols  Messages should be transmitted to destination  Only the recipient should see it.

Intro to Cryptography Lesson Introduction

Vigenére Cipher Kimberly Chiffens & Maria Jannelli.

Introduction to Cryptography Lecture 4. Caesar Cipher Gaius Julius Caesar (100 B.C.- 44 B.C.) General Politician Dictator of Rome Creator of Caesar Cipher.

Encryption. LEARNING OBJECTIVES: BY THE END OF THE LESSON YOU SHOULD KNOW. What encryption is and why it is important The basics of encryption techniques.

CHAPTER 14 ENCRYPTION AND DECRYPTION Sajina Pradhan

Computer Security By Rubel Biswas. Introduction History Terms & Definitions Symmetric and Asymmetric Attacks on Cryptosystems Outline.

Lecture 3 Page 1 CS 236 Online Basic Encryption Methods Substitutions –Monoalphabetic –Polyalphabetic Permutations.

Cryptography Introduction. Definition Origin Objectives Terminologies References Agenda.

Code Making/Breaking. What methods have you seen for encoding secret messages?

An NCTM Illuminations Lesson. Please cut out the two circles on the Caesar Shifter Activity Sheet in your packet.

CRYPTOGRAPHY G REEK WORD MEANING “ SECRET WRITING ”

Secure communication Informatics for economists II Jan Přichystal

Encryption with Keys and Passwords

(Principles of Informatioan security)

Cryptology in the U.S.—Then and Now

Computer and Data Security 4th Class

Basic Encryption Methods

Topics discussed in this section: 30-2 SYMMETRIC-KEY CRYPTOGRAPHY Symmetric-key cryptography started thousands of years ago when people needed.

Chapter 30 Cryptography Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Networks Encryption.

M3: Encryption r By Andrew Stringer.

Lesson 5: Simple Encryption

Cryptography Survey.

A Technical Seminar Presentation CLASSICAL CRYPTOGRAPHY

Chapter 3:Cryptography (16M)

PART VII Security.

Cryptography Survey.

Cryptography Hands on Learning Lab Activity (HOLLA) K-12 Partner School Initiative School of Computing.

Cryptography “The Secret Code Language”

National Cipher Challenge

Simple Encryption- Lesson 5

Fun with Cryptography The Science of Secrecy.

Lesson 7: Simple Encryption

Cryptography: Cesar Cipher

Basic Encryption Methods

Computer Security Chapter Two

Symmetric Encryption or conventional / private-key / single-key

10/7/2019 Created by Omeed Mustafa 1 st Semester M.Sc (Computer Science department) Cyber-Security.

Presentation transcript:

Introduction to Cryptography and Secure Communications  What is cryptography?  Encryption  Decryption

Key Terminology  Plain text  Example: “Hello”  Cipher text  Example: “Ifmmp”  Encryption  Example: Replace each letter with the next letter of the alphabet  Decryption  Example: Replace each letter with the previous alphabetical letter  Key  Example: a=b, m=n

How would you break this code?

Cipher Text ● Cipher text ● Text that has been transformed into an unreadable format. ● Code ● In cryptology, code means substituting a meaningful word or phrase with another word or phrase to change or hide meaning Copyright ETPRO 2010

Early Cryptology O Low literacy rates O Greek “scytale” O Translational methods O The Caesar Cipher

Monoalphabetic Ciphers O Specific O Consistent O Single letter to letter change O Easy to break

Caesar Cipher

Caesar Cipher –Shift of 7 ● Encrypt this message using the Caesar shifter- Shifting 7 ● ROME IS THE GREATEST EMPIRE. ● Decode this message ● YVTL DHZ UVA IBPSA PU H KHF. English Coded

Answers ● Correct Code =YVTL PZ AOL NYLHALZA LTWPYL. ● Decoded message = Rome was not built in a day.

Early Cryptology - Problems O Frequency Finger Prints

Using the Frequency Table Decode this Message TFNRIUJ UZV DREP KZDVJ SVWFIV KYVZI UVRKYJ; KYV MRCZREK EVMVI KRJKV FW UVRKY SLK FETV.

Try one on your own ● Encode a “common” message using the Caesar Cipher and any shift you choose and exchange the ciphertext with a classmate. ● The student receiving the ciphertext should decode the message and be able to tell what shift was used.

Modern Era Cryptography O WWII cryptography O German Lorenz Cipher machine O Rare languages used O Computer’s effect on cryptography

Modern Cryptography

Cryptography and You  How does cryptography affect your life?  What might happen if we did not have the protection it provides?  What makes codes harder to break?  How does math affect your life?