1. Chapter 6 Cryptography
CISSP Study Guide
BIS 4113/6113

2. Goals of Cryptography Confidentiality Integrity Authentication
Nonrepudiation
Prevents masquerading as the sender
AES Example

3. Historical Uses of Cryptography
Caesar Cipher
Civil War

4. World War II
Program Ultra
Enigma Machine
“Windtalkers”

5. Basic Terminology “Security through obscurity” Plain Text Cipher Text
Encryption
Decryption
Kerchoff’s Principle
Alogrithm public, keys kept private
Codes vs. Ciphers
Data at Rest / Data in Motion

6. Encyrption Algorithms
Symmetric Key
“Shared secret”
Shortcomings
Key distribution
Key regeneration every time user leaves group
Internet
Encryption
Decryption P C C P
Secret Key
Secret Key

7. Examples AES example Banking transactions Many VPN connections
One half of SSL (p.220)

8. Encyrption Algorithms
Asymmetric Key
Same key pair used for all users
Private key cannot be derived from public key
Shortcomings
Slow speed of operation
Internet
Encryption
Decryption P C C P
Receiver’s
Public Key
Receiver’s
Private Key

9. Other Comparisons (p.386) Symmetric Asymmetric Encryption Requirements
Single Shared Key
(2 Privates)
Key Pair Sets
(Public & Private)
Key Exchange
“Out of Band”
“In Band”
Adding
Additional Users
Not Scalable
Scalable
Operation
Fast
Slow
Amount of Data
Bulk Encryption
Small Blocks
Goals
Achieved
(Better?)
Confidentiality
Integrity
Authenticity
Nonrepudiation

10. Private Key Management
Key Transfer
Offline distribution
Public key transfer of private keys
Key Storage
Secondary storage
Non-volatile RAM
Key Use
Periodic rotation
Crytographic Life Cycle

11. Assignment #4 Generating Asymmetric Key Pairs
Send me your public key