An Introduction to Cryptography. What is cryptography? noun \krip- ˈ tä-grə-fē\ : the process of writing or reading secret messages or codes “Encryption”:

Slides:

Advertisements

Similar presentations

Cryptography Ch-1 prepared by: Diwan.

Advertisements

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

Computer Science 101 Data Encryption And Computer Networks.

Team Name: team13 Programmer: 陳則凱 b Tester: 劉典恆 b

Crytography Chapter 8.

A Presentation by: ~Ksenia Potapov ~Amariah Condon ~Janette Fong ~Janice Lau CRYPTOGRAPHY.

Cryptography The science of writing in secret code.

Cryptography. 2 Objectives Explain common terms used in the field of cryptography Outline what mechanisms constitute a strong cryptosystem Demonstrate.

Secure communication Informatics for economists II Jan Přichystal

Principles of Information Security, 2nd edition1 Cryptography.

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.

Cryptography: Keeping Your Information Safe. Information Assurance/Information Systems –What do we do? Keep information Safe Keep computers Safe –What.

McGraw-Hill©The McGraw-Hill Companies, Inc., Security PART VII.

1 Day 04- Cryptography Acknowledgements to Dr. Ola Flygt of Växjö University, Sweden for providing the original slides.

Cryptography & Encryption Secret Codes & The Advance of Technology.

Chapter 13: Electronic Commerce and Information Security Invitation to Computer Science, C++ Version, Fourth Edition SP09: Contains security section (13.4)

ENCRYPTION Jo Cromwell Cornelia Bradford. History of Encryption Encryption has been around since antiquity Cryptography began around 2,000 B.C in Egypt.

Encryption Methods By: Michael A. Scott

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

Cryptography Week-6.

Section 3.6: An Introduction to Cryptography

Cryptography Programming Lab

3.1 SERVICES AND MECHANISMS SERVICES AND MECHANISMS The International Telecommunication Union- Telecommunication Standardization Section (ITU-T) provides.

Encryption Presentation Jamie Roberts. Encryption Defined: n The process of converting messages, information, or data into a form unreadable by anyone.

Introduction to Information Security Chapter II : Classical Ciphers.

CS110: Computers and the Internet Encryption and Certificates.

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

T TT The Cryptography Istituto Tecnico Industriale “E.Divini” San Severino Marche.

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

Team Name: team13 Programmer: 陳則凱 b Tester: 劉典恆 b

Encryption: A Brief History Author: Margery Waldron.

Keeping Secrets with Digital Technology Information Assurance Program Anderson School of Management.

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

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

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Security PART VII.

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

Symmetric-Key Cryptography

CSCI 5857: Encoding and Encryption

THE SCIENCE, MATHEMATICS, AND ART OF PRIVACY BASIC STUFF 1 CRYPTOGRAPHY.

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)

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Security.

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

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

CRYPTOGRAPHY. TOPICS OF SEMINAR Introduction & Related Terms Categories and Aspects of cryptography Model of Network Security Encryption Techniques Public.

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

Section 2.5 Polyaphabetic Substitutions

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 Security PART VII.

Encryption CS110: Computer Science and the Internet.

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

Symmetric Cipher Model Plaintext input 1- encryption algorithm 2- secret key Encryption Cipher text output Cipher text input 1- Decryption algorithm 2-

Introduction to Cryptology Fall Definitions Digital encryption techniques are used to protect data in two ways: to maintain privacy and to prove.

Lecture 2 (Chapter 2) Classical Encryption Techniques Prepared by Dr. Lamiaa M. Elshenawy 1.

CRYPTOGRAPHY. DEFINITION Cryptography is the science of writing in secret code The earliest documented use began around 2,000 B.C in Egypt (Hieroglyphics)

Some of these PowerPoint pages were created by my friend Shawna Haider.

 Cryptography Melissa Pollis. What is Cryptography?  the science or study of the techniques of secret writing, especially code and cipher systems 

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

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.

History and Background Part 4: Transposition Ciphers

Cryptography CS Principles January 19, 2017.

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

Chapter 3:Cryptography (16M)

PART VII Security.

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:

An Introduction to Cryptography

What is cryptography? noun \krip- ˈ tä-grə-fē\ : the process of writing or reading secret messages or codes “Encryption”: to put into a format that is unreadable to unauthorized individuals “Cipher”: a method of encryption, or a code

Basics

History 1900 B.C. Egyptians encoded messages on clay tablets 100 B.C. Julius Caesar uses simple encryption to send messages in wartime 1466 A.D. Leon Battista Alberti invents polyalphabetic cipher

1835 Samuel Morse develops Morse Code 1940s Allies in World War II coded on enigma machines 1970s Data Encryption Standard (DES) was developed to encrypt electronic data History

Substitution Cipher Substitute one value for another

Substitution Cipher Common example: Cryptograms in newspapers

Substitution Cipher Original message: “plaintext”: Encrypted message: “ciphertext”

Solve this Substitution Cipher XKGTJDHI

Solution SECURITY

Ciphers in Popular Culture “National Treasure” (2004)

Keys They are what we use to secure the messages. (And to decrypt them!) They are shared to decrypt the message.

Keys “Asymmetric” cryptography has two keys: –Public key: used to encrypt the message –Private key: used to decrypt the message. (This one is secret) –Mathematically matched to protect the message

Vigenere Square Polyalphabetic cipher Column letter: plaintext Row Letter: key Example:

Vigenere Square Encrypt this word:

Solution VDOZF

Ciphers in Popular Culture “A Beautiful Mind” (2001)

Transposition Cipher Rearranges values within a block to create ciphertext Example: –“Caesar Block Cipher” –Uses 5X5 square –Message contains <25 characters Famously created by Julius Caesar!

Caesar Block Cipher Plaintext: LEARN ABOUT ENCRYPTION Ciphertext: L TROEA YNABEP EONT NUCI read across fill down

Caesar Block Cipher Try writing and encrypting your own message! Remember: <25 characters (including spaces) read across fill down Pass it to a friend to decrypt

Advanced Cryptography Using the types of techniques we learned, computers can encrypt files, s, etc. –Makes communication secure –But we still need to protect our keys and passwords!

Advanced Cryptography Technology Example

Real World Application Cryptanalysts: study information systems to find hidden aspects It’s their job to decrypt messages

Why does this matter to you? When you put your personal information on the internet, make it hard for thieves to steal Check your passwords:

Create a strong password Start with a weak password:  Linda!Marie1207 Come up with a secret key (4-6 characters)  puppy Encrypt text using the vigenere square:  Accsy!Bugxc1207 Strong Password

Jeopardy! What four aspects should your password include? In what profession do people break codes? Where does Gabe work? What is an encrypted message called? What cipher replaces one letter with another? What type of cryptography uses public and private keys? Who encoded messages on clay tablets? What is an unencrypted message called? What machine was used to encrypt messages in World War II?

Questions