Untitled Quiz

Introduction/Course Overview

• Book title: Cryptography and Network Security, Eighth Edition
• Author: William Stallings
• Copyright: 2020 Pearson Education, Inc.

Chapter 1: Information and Network Security Concepts

• Cybersecurity is a collection of tools, policies, security concepts, safeguards, guidelines, risk management approaches, actions, training, and technologies to protect cyberspace environments and users' assets.
• Cyber assets include connected devices, personnel, infrastructure, applications, services, and telecommunications systems
• Cybersecurity aims to maintain security properties of organizational and user assets against cyber threats.
• Key security objectives are: Availability, Integrity (including data authenticity and nonrepudiation), and Confidentiality.

Cybersecurity

• Cybersecurity involves tools, policies, and security concepts to safeguard cyberspace environments
• Cybersecurity helps protect organizational and user assets, which include both connected devices and personnel
• Cybersecurity also covers the entirety of information transmitted or stored within the cyberspace environment
• It ensures that security properties are maintained and attained.

Information Security

• Preserves confidentiality, integrity, and availability of information as well as other factors like authenticity, accountability, nonrepudiation, and reliability

Network Security

• Protects networks and services from unauthorized modification, destruction, or disclosure
• It ensures that network performance is correct with no harmful side effects

Security Objectives

• Confidentiality: Two key concepts are Data confidentiality, which protects private/confidential information from unauthorized disclosure and Privacy, which assures individuals control over their data and who has access to it.
• Integrity: Two related concepts are Data integrity (ensuring data and programs are only changed in specified/authorized ways) and System integrity (ensuring a system performs intended functions without unauthorized manipulation)
• Availability: Protects systems to ensure prompt availability and service for authorized users

Security Objectives (Diagram)

• Key objectives include Confidentiality (plus privacy), Integrity (plus authenticity and non-repudiation), Availability and Accountability.

Computer Security Challenges

• Security is not simple, needs proactive procedures
• Potential attacks on security features need to be considered
• Security procedures can be counter-intuitive, requiring careful design
• Security mechanisms are complex, involving more than a single algorithm
• Security is a battle of wits between perpetrators and designers
• Security investment may not be immediately apparent, but failures can cause significant damage.
• Strong security can sometimes appear to impede efficient operation

OSI Security Architecture

• Security Attack: An action that compromises information security of an organization
• Security Mechanism: A process (or device) designed to detect, prevent or recover from a security attack
• Security Service: A communication/processing service that enhances security

Threats and Attacks

• Threat: A potential for violating security due to a circumstance, capability, action or event
• Attack: A deliberate attempt to evade security policies and violate system security

Passive Attacks

• Message Contents: Release of message contents
• Traffic Analysis: Monitoring transmissions, but not altering the content

Active Attacks

• Masquerade: One entity pretending to be a different entity
• Replay: Capturing and retransmitting data units for unauthorized use
• Modification of data: Altering data
• Denial of service: Preventing or inhibiting use of communications facilities

Authentication

• Single message: Verifying the sender of a single message
• Ongoing interaction: Assuring that communicating entities are authentic and the connection isn't compromised
• Peer entity authentication: Verifying the identity of interacting entities in an association.
• Data origin authentication: Verifying the source and integrity of a data unit.

Access Control

• Limiting and controlling access to host systems and applications through communication links

Data Confidentiality

• Protects transmitted data from passive attacks.
• Broadest service: Protecting all user data transmitted over a period.
• Narrower service: Protecting specific messages or fields.
• Protecting traffic flow from analysis.

Data Integrity

• Protecting a stream of messages, a single message, or specific fields in a message for assurance they haven't been altered
• Connection-oriented services confirm message integrity, preventing duplication, alteration, and reordering.
• Connectionless integrity services assure integrity of single messages

Nonrepudiation

• Prevents sender or receiver from denying a transmitted message
• Proving that a message was sent/received

Availability Service

• Protects system availability, addressing denial-of-service attacks
• Dependent on proper management and control of system resources/access control service

Security Mechanisms

• Cryptographic Algorithms: Reversible, irreversible (hash, message authentication codes) mechanisms for encryption, decryption.
• Digital Signatures: Data appended/transformed to prove source and data integrity and prevent forgery
• Authentication Exchange: Mechanisms for verifying entity identity
• Traffic Padding: Inserting bits into gaps in the data stream
• Routing Control: Selecting security routes, especially in suspected breaches
• Notarization: Use of a trusted third party to assure data properties.
• Access Control: Mechanisms managing access rights

Cryptographic Algorithms (Types)

• Keyless: Cryptographic hash functions, pseudo-random number generators
• Single-Key: Block ciphers, stream ciphers, Message Authentication Codes (MACs)
• Two-Key: Asymmetric encryption, digital signatures, key exchange, user authentication

Keyless Algorithms

• Deterministic functions with cryptographic properties (hash functions, pseudo-random number generators)

Single-Key Algorithms

• Depends on a single key used for both encryption and decryption, using symmetric encryption algorithms (block ciphers and stream ciphers)
• Examples include message authentication codes (MACs)

Asymmetric Algorithms

• Uses two separate keys (public and private) for encryption and decryption, used primarily for digital signatures, key exchange, and user authentication.

Network Protocols

• Includes protocols like IPsec, TLS, HTTPS, SSH, IEEE 802.11i, S/MIME for communication security.

Communications Security

• Deals with protecting communication through the network, including passive and active attacks

Device Security

• Focuses on securing network devices (routers, switches, client systems etc)
• Primary concerns are intrusions, malicious software, and resource overloads

Firewall

• Limits network access based on security policies and filters data traffic

Intrusion Detection

• Systems that detect and monitor activity for attempts to access/alter resources without authorization

Intrusion Prevention

• Systems that detect and stop intrusive activities before reaching the target

Trust Model

• Willingness of one party to be vulnerable based on the actions of another party.
• Related concepts include: Trustworthiness: deservability of trust Propensity to trust: a tendency to trust others Risk: Measure of threat

Trustworthiness of an Individual

• Policies implemented regarding security during employment

Trustworthiness of an Organization

• Establishing trust relationships with external organizations.
• Documenting agreements, such as contracts and service level agreements, and establishing trust across multiple organizations

Trustworthiness of Information Systems

• Addresses degree that information systems maintain confidentiality, integrity, and availability.
• Security functionality: security features implemented
• Security assurances: confidence security functionality is effective.

Establishing Trust Relationships

• Validated trust: Relies on evidence about the trusted entity
• Direct historical trust: Relies on the organization's past security record.
• Mediated trust: Third-party mediates the trust between parties.
• Mandated trust: Trust established by a superior entity.