Lecture Data security and encryption - Chapter 1: Overview

This chapter presents the following content: Outline of the course is discussed; topic roadmap & standards organizations; security concepts; X.800 security architecture; security attacks, services, mechanisms; models for network (access) security.

(CSE348)

Assistant ProfessorComsats Institute of Information 

Technology, Islamabad

Course Outline

Part Seven: Legal and Ethical Issues: 

Deals with the legal and ethical issues related

to computer and network security.

Course Outline

Chapter 1 Overview

1.1 Computer Security Concepts

1.2 The OSI Security Architecture

1.3 Security Attacks

1.4 Security Services

1.5 Security Mechanisms

1.6 A Model for Network Security

1.7 Recommended Reading and Web Sites

1.8 Key Terms and Review Questions

Course Outline

PART ONE SYMMETRIC CIPHERS

Chapter 2 Classical Encryption Techniques

2.1 Symmetric Cipher Model

2.2 Substitution Techniques

2.3 Transposition Techniques

2.4 Rotor Machines

2.5 Steganography

2.6 Recommended Reading and Web Sites

2.7 Key Terms and Review Questions

Course Outline

Chapter 3 Block Ciphers and the Data Encryption

Standard

3.1 Block Cipher Principles

3.2 The Data Encryption Standard (DES)

3.3 A DES Example

3.4 The Strength of DES

3.5 Differential and Linear Cryptanalysis

3.6 Block Cipher Design Principles

3.7 Recommended Reading and Web Site

3.8 Key Terms and Review Questions

Course Outline

Chapter 4 Basic Concepts in Number Theory and

Finite Fields

4.1 Divisibility and the Division Algorithm

4.2 The Euclidean Algorithm

4.3 Modular Arithmetic

4.4 Groups, Rings, and Fields

4.5 Finite Fields of the Form GF(p)

4.6 Polynomial Arithmetic

4.7 Finite Fields of the Form GF(2n)

4.8 Recommended Reading and Web Sites

4.9 Key Terms and Review Questions

Course Outline

Chapter 5 Advanced Encryption Standard

5.1 The Origins AES

5.2 AES Structure

5.3 AES Round Functions

5.4 AES Key Expansion

5.5 An AES Example

5.6 AES Implementation

5.7 Recommended Reading and Web Sites

5.8 Key Terms and Review Questions

Course Outline

Chapter 6 Block Cipher Operation

6.1 Multiple Encryption and Triple DES

6.2 Electronic Codebook Mode

6.3 Cipher Block Chaining Mode

6.4 Cipher Feedback Mode

6.5 Output Feedback Mode

6.6 Counter Mode

6.7 XTS Mode for Block-Oriented Storage Devices

6.8 Recommended Web Site

6.9 Key Terms and Review Questions

Course Outline

Chapter 7 Pseudorandom Number Generation and

Stream Ciphers

7.1 Principles of Pseudorandom Number Generation

7.2 Pseudorandom Number Generators

7.3 Pseudorandom Number Generation Using a Block

Course Outline

PART TWO ASYMMETRIC CIPHERS

Chapter 8 More Number Theory

8.1 Prime Numbers

8.2 Fermat’s and Euler’s Theorems

8.3 Testing for Primality

8.4 The Chinese Remainder Theorem

8.5 Discrete Logarithms

8.6 Recommended Reading and Web Sites

8.7 Key Terms and Review Questions

Course Outline

Chapter 9 Public-Key Cryptography and RSA

9.1 Principles of Public-Key Cryptosystems

9.2 The RSA Algorithm

9.3 Recommended Reading and Web Sites

9.4 Key Terms and Review Questions

Course Outline

Chapter 10 Other Public-Key Cryptosystems

10.1 Diffie-Hellman Key Exchange

10.2 ElGamal Cryptosystem

10.3 Elliptic Curve Arithmetic

10.4 Elliptic Curve Cryptography

10.5 Pseudorandom Number Generation Based on an

Asymmetric Cipher

10.6 Recommended Reading and Web Sites

10.7 Key Terms and Review Questions

Course Outline

PART THREE CRYPTOGRAPHIC DATA

INTEGRITY ALGORITHMS

Chapter 11 Cryptographic Hash Functions

11.1 Applications of Cryptographic Hash Functions

11.2 Two Simple Hash Functions

11.3 Requirements and Security

11.4 Hash Functions Based on Cipher Block Chaining

11.5 Secure Hash Algorithm (SHA)

11.6 SHA-3

11.7 Recommended Reading and Web Sites

11.8 Key Terms and Review Questions

Course Outline

Chapter 12 Message Authentication Codes

12.1 Message Authentication Requirements

12.2 Message Authentication Functions

12.3 Message Authentication Codes

12.4 Security of MACs

12.5 MACs Based on Hash Functions:HMAC

12.6 MACs Based on Block Ciphers: DAA and CMAC

12.7 Authenticated Encryption: CCM and GCM

12.8 Pseudorandom Number Generation Using Hash

Functions and MACs

12.9 Recommended Reading

12.10 Key Terms and Review Questions

Course Outline

Chapter 13 Digital Signatures

13.1 Digital Signatures

13.2 ElGamal Digital Signature Scheme

13.3 Schnorr Digital Signature Scheme

13.4 Digital Signature Standard (DSS)

13.5 Recommended Reading and Web Sites

13.6 Key Terms and Review Questions

Course Outline

PART FOUR MUTUAL TRUST

Chapter 14 Key Management and Distribution

14.1 Symmetric Key Distribution Using Symmetric

14.5 Public Key Infrastructure

14.6 Recommended Reading and Web Sites

14.7 Key Terms and Review Questions

Course Outline

Chapter 15 User Authentication Protocols

15.1 Remote User Authentication Principles

15.2 Remote User Authentication Using Symmetric

Encryption

15.3 Kerberos

15.4 Remote User Authentication Using Asymmetric

Encryption

15.5 Federated Identity Management

15.6 Recommended Reading and Web Sites

15.7 Key Terms and Review Questions

Course Outline

PART FIVE NETWORK AND INTERNET

SECURITY

Chapter 16 Transport-Level Security

16.1 Web Security Issues

16.2 Secure Sockets Layer (SSL)

16.3 Transport Layer Security (TLS)

16.4 HTTPS

16.5 Secure Shell (SSH)

16.6 Recommended Reading and Web Sites

16.7 Key Terms and Review Questions

Course Outline

Chapter 17 Wireless Network Security

17.1 IEEE 802.11 Wireless LAN Overview

17.2 IEEE 802.11i Wireless LAN Security

17.3 Wireless Application Protocol Overview

17.4 Wireless Transport Layer Security

17.5 WAP End-to-End Security

17.6 Recommended Reading and Web Sites

17.7 Key Terms and Review Questions

Course Outline

Chapter 18 Electronic Mail Security

18.1 Pretty Good Privacy (PGP)

18.2 S/MIME

18.3 Domain Keys Identified Mail (DKIM)

18.4 Recommended Web Sites

18.5 Key Terms and Review Questions

Course Outline

Chapter 19 IP Security

19.1 IP Security Overview

19.2 IP Security Policy

19.3 Encapsulating Security Payload

19.4 Combining Security Associations

19.5 Internet Key Exchange

19.6 Cryptographic Suites

19.7 Recommended Reading and Web Sites

19.8 Key Terms and Review Questions

Chapter 0 – Reader’s Guide

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 that we have made our position 

unassailable. 

—The Art of War, Sun Tzu

• Mutual trust: Study of techniques and 

algorithms for providing mutual trust in two main areas

• First, key management and distribution deals with establishing trust in the encryption keys used between two communicating entities

• Second, user authentication deals with 

establish trust in the identity of a 

communicating partner

• Network security: Covers the use of 

cryptographic algorithms in network protocols and network applications

• Computer security: The term refer to the 

security of computers against intruders (e.g., hackers) and malicious software (e.g., viruses)

• Typically, the computer to be secured is 

attached to a network and the bulk of the 

threats arise from the network

Standards Organizations

• National Institute of Standards & Technology (NIST)

Key Security Concepts

CIA Triad

• These three concepts form what is often 

referred to as the CIA triad Figure above. 

• The three concepts embody the fundamental security objectives for both data and for 

information and computing services. 

• FIPS PUB 199 provides a useful 

characterization of these three objectives in 

terms of requirements and the definition of a loss of security in each category

• A loss of confidentiality is the unauthorized 

disclosure of information

• Two of the most commonly mentioned are:

CIA Triad

• Authenticity: The property of being genuine and being able to be verified and trusted; 

confidence in the validity of a transmission, a message, or message originator

CIA Triad

• Accountability: The security goal that 

generates the requirement for actions of an 

entity to be traced uniquely to that entity

Levels of Impact

• can define 3 levels of impact from a security breach

– Low

– Moderate

– High

Levels of Impact

• degradation in mission capability to an extent and duration that the organization is able to 

Levels of Impact

• cause a significant degradation in mission 

capability and effectiveness of the functions is significantly reduced; 

• result in significant damage to oganizational assets; 

• result in significant financial loss; or 

• result in significant harm to individuals that 

does not involve loss of life or serious, life­

loss might

• Student enrollment information may have a 

moderate confidentiality rating. 

Confidentiality Example

• While still covered by FERPA, this 

information is seen by more people on a daily basis, is less likely to be targeted than grade 

cause harm to the hospital. 

Integrity Example

• The database needs to be restored to a trusted basis quickly, and it should be possible to trace the error back to the person responsible

• Patient allergy information is an example of an asset with a high requirement for integrity

•  Inaccurate information could result in serious harm or death to a patient and expose the 

hospital to massive liability

Availability Example

• The more critical a component or service, the higher is the level of availability required. 

• Consider a system that provides authentication services

• An interruption of service results in the 

inability for customers to access computing 

resources. 

• loss of service translates into a large financial loss productivity and potential customer loss

Computer Security Challenges

1 not simple

2 must consider potential attacks

3 procedures used counter-intuitive

4 involve algorithms and secret info

5 must decide where to deploy mechanisms

6 battle of wits between attacker / admin

7 not perceived on benefit until fails

8 requires regular monitoring

9 too often an after-thought

regarded as impediment to using system

OSI Security Architecture

Aspects of Security

• Security attack: Any action that compromises the security of information owned by an 

organization. 

Aspects of Security

• Security mechanism: A process (or a device incorporating such a process) that is designed 

to detect, prevent, or recover from a security attack. 

Aspects of Security

• Security service: A processing or 

communication service that enhances the 

security of the data processing systems and the information transfers of an organization. 

Passive Attacks

Active Attacks

• Instead, the goal is to detect active attacks and to  recover from any disruption/or delays caused by  them.

Security Service

– enhance security of data processing systems and  information transfers of an organization

– intended to counter security attacks

– using one or more security mechanisms 

– often replicates functions normally associated with  physical documents

• which, for example, have signatures, dates; need 

protection from disclosure, tampering, or destruction; 

be notarized or witnessed; be recorded or licensed

Security Mechanism

• feature designed to detect, prevent, or recover from a security attack

Security Mechanisms (X.800)

• specific security mechanisms:

– encipherment, digital signatures, access controls,  data integrity, authentication exchange, traffic 

padding, routing control, notarization

• pervasive security mechanisms:

– trusted functionality, security labels, event 

detection, security audit trails, security recovery

Model for Network Security

Model for Network Security

Model for Network Access Security

Model for Network Access Security