Confidentiality Using Symmetric Encryption
Lecture 9
Prof. Ren
1
Outline
Placement of Encryption
Potential Locations for Confidentiality Attacks
Link vs. End-to-End Encryption Traffic Confidentiality
Key Distribution Random Number Generation
Prof. Ren
Advanced Encryption Standard (AES)
Lecture 8
Prof. Ren
1
Background
On January 2, 1997, NIST began the process of choosing a replacement for DES. The replacement would be called Advanced Encryption Standard, or AES. AES is required to have block length 1
Block Cipher Encryption Modes
Lecture 7
Prof. Ren
1
Electronic Codebook (ECB) Mode
Simplest mode Plaintext is handled 64 bits at a time Each block is encrypted using the same key For a given key, there is a unique ciphertext for every 64-bit block of pla
Security of DES and Differential Cryptanalysis
Lecture 6
Prof. Ren
1
Security of DES
Two major issues:
Length of key (56 bits) S-boxes
Prof. Ren
2
1
Security of DES-Length of key
With a key length of 56 bits, there are 256 possible keys, which is approx
Data Encryption Standard (DES)
Lecture 5
Prof. Ren
1
Background
In the 1960s, IBM set up a research project in computer cryptography led by Horst Feistel. The project concluded in 1972, with the development of an algorithm with the designation LUCIFER. I
Block Cipher Principles
Lecture 4
Prof. Ren
1
Outline
Since virtually all symmetric block encryption algorithms in current use are based on a structure referred to as a Feistel block cipher. For this reason, it is important to examine the design principl
Rotor Machines and Breaking The Enigma
Prof. Ren
1
Rotor Machines
Before modern ciphers, rotor machines were most common product cipher Widely used in WWII
German Enigma, Japanese Purple, Allied Hagelin,
Implemented a very complex, varying substitution ci
Classical Cryptosystems Example of some bad ciphers
Jian Ren
At the late 16th century, Mary Queen trusted her encryption was completely secure. Therefore, she relies on this encryption system to communicate with her trusted people and planed her conspirac
Cryptography and Network Security
Lecture 1: Introduction Prof. Ren
The art of war teaches us to rely not on the likelihood of the enemy's not coming, but on our own readiness to receive him; not on the chance of his not attacking, but rather on the fact
ECE816: Cryptography and Network Security
Course Information
Prof. Jian Ren
Textbook
Cryptography and Network Security
Fourth Edition Author: By William Stallings Publisher: Prentice Hall.
Prof. Ren
2
1
Reference Books
Cryptography and Data Security
Autho
Homework #1
Due on Feb. 11, 2009
1. Why is the one-time pad encryption unconditionally secure against eavesdropping? 2. Why are simple substitution ciphers and transposition ciphers, even though extremely vulnerable to the frequency analysis attack, still
Chapter 8 Network Security
All material copyright 1996-2007 J.F Kurose and K.W. Ross, All Rights Reserved 8: Network Security 8-1
Chapter 8: Network Security
Chapter goals: understand principles of network security:
cryptography and its many uses beyond c