Data Security and Encryption (CSE348) 1. Dr. Basit Raza Assistant Professor Comsats Institute of Information Technology, Islamabad 2.

Data Security and Encryption

(CSE348)

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Dr. Basit Raza

Assistant Professor

Comsats Institute of Information Technology, Islamabad

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Course Outline

In this course we will follow the mentioned book

Cryptography and Network Security”,

5th Edition by William Stallings.

The book is organized into seven parts:

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Course Outline

Part One: Symmetric Ciphers:

Provides a survey of symmetric encryption, including classical and modern algorithms. The emphasis is on the two most important algorithms,

the Data Encryption Standard (DES) and the Advanced Encryption Standard (AES).This part also covers the most important stream encryption

algorithm,RC4,and the important topic of pseudorandom number generation.

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Course Outline

Part Two: Asymmetric Ciphers:

Provides a survey of public-key algorithms,

including RSA (Rivest-Shamir-Adelman) and elliptic curve.

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Course Outline

Part Three: Cryptographic Data Integrity Algorithms:

Begins with a survey of cryptographic

hash functions. This part then covers two approaches to data integrity that rely on cryptographic hash functions: message authentication codes and digital signatures.

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Course Outline

Part Four: Mutual Trust:

Covers key management and key distribution topics and then covers user authentication techniques.

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Course Outline

Part Five: Network Security and Internet Security:

Examines the use of cryptographic

algorithms and security protocols to provide security over networks and the Internet. Topics covered include transport-level security, wireless network security, e-mail security, and IP security.

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Course Outline

Part Six: System Security:

Deals with security facilities designed to protect a

computer system from security threats, including intruders, viruses, and worms. This part also looks at firewall technology.

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Course Outline

Part Seven: Legal and Ethical Issues:

Deals with the legal and ethical issues related

to computer and network security.

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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

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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



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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


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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)



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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



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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


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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 Cipher

7.4 Stream Ciphers

7.5 RC4

7.6 True Random Numbers

7.7 Recommended Reading


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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



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Course Outline

Chapter 9 Public-Key Cryptography and RSA

9.1 Principles of Public-Key Cryptosystems

9.2 The RSA Algorithm



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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



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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



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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 Questions22

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)



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Course Outline

PART FOUR MUTUAL TRUST

Chapter 14 Key Management and Distribution

14.1 Symmetric Key Distribution Using Symmetric Encryption

14.2 Symmetric Key Distribution Using Asymmetric Encryption

14.3 Distribution of Public Keys

14.4 X.509 Certificates

14.5 Public Key Infrastructure



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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



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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)



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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



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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


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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



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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

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Roadmap

• Cryptographic algorithms

• Mutual Trust

• Network Security

• Computer Security

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Roadmap

• Cryptographic algorithms: Study of techniques for ensuring the secrecy and/or authenticity of information

• Three main areas of study in this category are: 1. symmetric encryption,

2. asymmetric encryption,

3. cryptographic hash functions, with the related topics of message authentication codes and digital signatures.

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Roadmap

• 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.

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Roadmap

• 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.

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Standards Organizations

• National Institute of Standards & Technology (NIST)

• Internet Society (ISOC)

• International Telecommunication Union Telecommunication Standardization Sector (ITU-T)

• International Organization for Standardization (ISO)

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Chapter 1 – Introduction

• The combination of space, time, and strength that must be considered as the basic elements of this theory of defense makes this a fairly complicated matter. Consequently, it is not easy to find a fixed point of departure.. — On War, Carl Von Clausewitz

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Computer Security

• the protection afforded to an automated information system in order to attain the applicable objectives of preserving the integrity, availability and confidentiality of information system resources (includes hardware, software, firmware, information/data, and telecommunications)

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Key Security Concepts

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CIA Triad

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• 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.

CIA Triad

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• Confidentiality (covers both data confidentiality and privacy):

• preserving authorized restrictions on information access and disclosure, including means for protecting personal privacy and proprietary information.

• A loss of confidentiality is the unauthorized disclosure of information.

CIA Triad

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• Integrity (covers both data and system integrity):

• Guarding against improper information modification or destruction, and includes ensuring information non-repudiation and authenticity.

• A loss of integrity is the unauthorized modification or destruction of information.

CIA Triad

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• Availability: Ensuring timely and reliable access to and use of information. A loss of availability is the disruption of access to or use of information or an information system.

• Although the use of the CIA triad to define security objectives is well established, some in the security field feel that additional concepts are needed to present a complete picture.

• Two of the most commonly mentioned are:

CIA Triad

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• 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

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• 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

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Levels of Impact

• Low: The loss could be expected to have a limited adverse effect on organizational operations, organizational assets, or individuals.

• A limited adverse effect means that, for example, the loss of confidentiality, integrity, or availability might causes effect.

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Levels of Impact

• degradation in mission capability to an extent and duration that the organization is able to perform its primary functions, but the effectiveness of the functions is noticeably reduced;

• result in minor damage to organizational assets;

• result in minor financial loss; or

• result in minor harm to individuals.

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Levels of Impact

• Moderate: The loss could be expected to have a serious adverse effect on organizational operations, organizational assets, or individuals. A serious adverse effect means that, for example, the loss might

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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-threatening injuries.

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Levels of Impact

• High: The loss could be expected to have a severe or catastrophic adverse effect on organizational operations, organizational assets, or individuals. A severe or catastrophic adverse effect means that, for example, the loss might

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Levels of Impact

• cause a severe degradation in or loss of mission capability to an extent and duration that the organization is not able to perform one or more of its primary functions;

• result in major damage to organizational assets;

• result in major financial loss; or

• result in severe or catastrophic harm to individuals involving loss of life or serious life threatening injuries.

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Examples of Security Requirements

• confidentiality – student grades

• integrity – patient information

• availability – authentication service

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Examples of Security Requirements

• confidentiality – student grades

• integrity – patient information

• availability – authentication service

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Confidentiality Example

• Student grade information is an asset whose confidentiality is considered to be highly important by students.

• Grade information should only be available to students, their parents, and employees that require the information to do their job.

• Student enrollment information may have a moderate confidentiality rating.

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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 information, and results in less damage if disclosed.

• Directory information, such as lists of students or faculty or departmental lists, may be assigned a low confidentiality rating.

• Freely available to the public and published on a school's Web site.

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Integrity Example

• Consider a hospital patient's allergy information stored in a database.

• The doctor should be able to trust that the information is correct and current.

• Now suppose that an employee (e.g., a nurse) who is authorized to view and update this information deliberately falsifies the data to cause harm to the hospital.

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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.

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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.

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Computer Security Challenges

1. not simple2. must consider potential attacks3. procedures used counter-intuitive4. involve algorithms and secret info5. must decide where to deploy mechanisms6. battle of wits between attacker / admin7. not perceived on benefit until fails8. requires regular monitoring9. too often an after-thought10. regarded as impediment to using system

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OSI Security Architecture

• ITU-T X.800 “Security Architecture for OSI”

• defines a systematic way of defining and providing security requirements

• for us it provides a useful, if abstract, overview of concepts we will study

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Aspects of Security

• consider 3 aspects of information security:– security attack

– security mechanism

– security service

• note terms– threat – a potential for violation of security

– attack – an assault on system security, a deliberate attempt to evade security services

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Aspects of Security

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

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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.

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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.

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Passive Attacks

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Passive Attacks

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• A useful means of classifying security attacks, used both in X.800 and RFC 2828, is in terms of passive attacks and active attacks.

• A passive attack attempts to learn or make use of information from the system but does not affect system resources.

• Passive attacks are in the nature of eavesdropping on, or monitoring of, transmissions. The goal of the opponent is to obtain information that is being transmitted.

Passive Attacks

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• Two types of passive attacks are:

+ release of message contents

+ traffic analysis - monitor traffic flow to determine location and identity of communicating hosts and could observe the frequency and length of messages being exchanged

Active Attacks

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Active Attacks

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• Active attacks involve some modification of the data stream or the creation of a false stream

• can be subdivided into four categories: • masquerade of one entity as some other• replay previous messages• modify/alter (part of) messages in transit to produce an unauthorized effect• denial of service - prevents or inhibits the normal use or management of communications facilities

Active Attacks

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• Active attacks present the opposite characteristics of passive attacks.

• Whereas passive attacks are difficult to detect, measures are available to prevent their success.

• Quite difficult to prevent active attacks absolutely, because of the wide variety of potential physical, software, and network vulnerabilities.

• 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

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Security Services

• X.800:“a service provided by a protocol layer of

communicating open systems, which ensures adequate security of the systems or of data transfers”

• RFC 2828:“a processing or communication service provided by

a system to give a specific kind of protection to system resources”

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Security Services (X.800)• Authentication - assurance that communicating

entity is the one claimed– have both peer-entity & data origin authentication

• Access Control - prevention of the unauthorized use of a resource

• Data Confidentiality –protection of data from unauthorized disclosure

• Data Integrity - assurance that data received is as sent by an authorized entity

• Non-Repudiation - protection against denial by one of the parties in a communication

• Availability – resource accessible/usable73

Security Mechanism

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

• no single mechanism that will support all services required

• however one particular element underlies many of the security mechanisms in use:– cryptographic techniques

• hence our focus on this topic

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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

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Model for Network Security

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Model for Network Security

• using this model requires us to: 1. design a suitable algorithm for the security

transformation 2. generate the secret information (keys) used by

the algorithm 3. develop methods to distribute and share the

secret information 4. specify a protocol enabling the principals to use

the transformation and secret information for a security service

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Model for Network Access Security

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Model for Network Access Security

• using this model requires us to: 1. select appropriate gatekeeper functions to

identify users 2. implement security controls to ensure only

authorised users access designated information or resources

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Summary

• Outline of the course is discussed

• topic roadmap & standards organizations

• security concepts:– confidentiality, integrity, availability

• X.800 security architecture

• security attacks, services, mechanisms

• models for network (access) security

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Data Security and Encryption (CSE348) 1. Dr. Basit Raza Assistant Professor Comsats Institute of Information Technology, Islamabad 2.

Documents

data security

system security

internet security

course outlinepart

security attacks

security services

security mechanisms

email security