14-02-2013, 10:48 AM
Cryptography
Cryptography.ppt (Size: 746 KB / Downloads: 65)
Learning Objectives
Chronicle the most significant events and discoveries in the history of cryptology
Explain the basic principles of cryptography
Describe the operating principles of the most popular tools in the area of cryptography
List and explicate the major protocols used for secure communications
Discuss the nature and execution of the dominant methods of attack used against cryptosystems
Introduction
Cryptography: process of making and using codes to secure transmission of information
Encryption: converting original message into a form unreadable by unauthorized individuals
Cryptanalysis: process of obtaining original message from encrypted message without knowing algorithms
Cryptology: science of encryption; combines cryptography and cryptanalysis
Foundations of Cryptology
With emergence of technology, need for encryption in information technology environment greatly increased
All popular Web browsers use built-in encryption features for secure e-commerce applications
Cipher Methods
Plaintext can be encrypted through bit stream or block cipher method
Bit stream: each plaintext bit transformed into cipher bit one bit at a time
Block cipher: message divided into blocks (e.g., sets of 8- or 16-bit blocks) and each is transformed into encrypted block of cipher bits using algorithm and key