Domain 3.2: Security Architecture and Engineering

Question 1

Define:

Key or Cryptographic Key or Cryptovariable

Answer 1

Data input in an encryption process, controlling the algorithm’s output to ensure secure data transformation.

A piece of data used as input for an encryption algorithm to transform plaintext data into ciphertext or vice versa. The key determines the specific output of an encryption algorithm, thus ensuring that only those who possess the correct key can decrypt the data. Keys are used in a variety of contexts, including secure communication, data protection, and digital signatures.

For more information, view this lecture on The Encryption We Use Today. Or visit this Wikipedia page.

Question 2

Define:

Key Pair

Answer 2

A set of related cryptographic keys in public-key cryptography, one public and one private, used for secure communications.

A key pair in public-key cryptography consists of a private key, which is kept secret, and a public key, which can be shared publicly. The keys are mathematically related, allowing for secure data encryption, digital signatures, and key exchanges. Key pairs enable functions such as SSL/TLS for secure web communications and PGP for secure emails.

For more information, view this lecture on Asymmetric Encryption- Part 1. Or visit this Wikipedia page.

Question 3

Define:

Key Recovery

Answer 3

The retrieval and restoration of a lost or compromised cryptographic key, essential for encrypted data access.

The process of retrieving and restoring a lost or compromised cryptographic key. It is used to ensure the availability and integrity of encrypted data in the event of a key loss or failure. Examples of key recovery methods include backup and recovery of keys, secure key escrow, and keyless recovery using a trusted third party.

For more information, view this lecture on Digital Signatures.

Question 4

Define:

Key Space

Answer 4

The total set of possible keys for a cryptographic algorithm, defining the potential for key uniqueness.

In cryptography, key space refers to the set of all possible keys that can be used with a cryptographic algorithm, defining the limits of potential key values. The size of the key space (i.e., the total number of distinct keys) is determined by the key length, impacting the algorithm’s resistance to brute force attacks. For example, a 128-bit keyspace has 2^128 possible keys.

For more information, visit this Wikipedia page.

Question 5

Define:

Key Space Clumping

Answer 5

A clustering of keys within a cryptographic key space, potentially leading to reduced encryption strength.

A term related to cryptography and the distribution of potential keys within the key space, which is the set of all possible keys that can be used with a cryptographic algorithm. Keyspace clumping occurs when keys are not evenly distributed throughout the key space, potentially leading to clusters or groups of keys that are more likely to be chosen or tested than others. This uneven distribution can introduce vulnerabilities, as it may reduce the effective size of the key space and make the encryption system easier to breach through methods such as brute force attacks. Properly designed cryptographic systems aim to avoid key space clumping to ensure that all keys are equally likely to be generated and that the key space is fully utilized to maintain the strength of cryptographic protection.

Question 6

Define:

Key Stretching

Answer 6

Applying a cryptographic function multiple times to a key to enhance its length and security.

The process of applying a cryptographic function multiple times to a password or key to increase its effective length and security. It is used to protect against brute-force attacks and dictionary attacks by making it computationally infeasible to guess or crack the key. Examples of key stretching algorithms include PBKDF2 and Argon2.

For more information, view this lecture on Attacks on Our Cryptography- Part 1. Or visit this Wikipedia page.

Question 7

Define:

Key-Encryption-Key

(KEK)

Answer 7

A secret key used for encrypting other keys, an integral part of secure key management systems.

A secret key used for encrypting and decrypting other keys. It is commonly used in key management systems to securely store and protect keys. Examples include a KEK used to encrypt keys for secure data transmission, a KEK used to encrypt keys for secure access to a cloud storage system, and a KEK used to encrypt keys for secure access to a financial database.

Question 8

Define:

Keylogger

Answer 8

A tool that records keyboard input, monitoring user activity and capturing sensitive information.

A type of software or hardware device used to track and record keystrokes on a computer or device. It is used to monitor user activity and capture sensitive information such as passwords and credit card numbers. Examples of keyloggers include malware-based keyloggers, hardware-based keyloggers, and keylogger software for parental control.

For more information, view this lecture on Type 1 Authentication - “Something You Know” or “Knowledge Factors”. Or visit this Wikipedia page.

Question 9

Define:

Keystream

Answer 9

A sequence of bits used to encrypt plaintext in stream ciphers.

A keystream is a continuous sequence of pseudo-random bits generated by a cryptographic algorithm, used to encrypt plaintext by combining with it—often via XOR—to produce ciphertext. The security of stream ciphers critically depends on the unpredictability and uniqueness of the keystream for each encryption session.

For more information, view this lecture on Symmetric Encryption- Part 2. Or visit this Wikipedia page.

Question 10

Define:

KillDisk Malware

Answer 10

Malware that destroys system data, sometimes part of ransomware attacks, threatening data loss unless a ransom is paid.

A type of malware that targets and destroys data on a system, often as part of a larger ransomware attack. It is used to extort money from victims by threatening to permanently delete their data unless a ransom is paid. Examples of KillDisk malware include the Petya and NotPetya attacks.

Question 11

Define:

Known Key

Answer 11

A cryptographic key that has been exposed, compromising encryption efforts.

A Known Key refers to an encryption key that is already in the hands of unauthorized parties or widely accessible due to poor security practices. Its exposure renders any encryption relying on it ineffective, as adversaries can use the key to decrypt confidential data. Preventing known key incidents is crucial for maintaining the integrity of cryptographic systems, emphasizing secure key storage and periodic key rotation.

For more information, view this lecture on Attacks on Our Cryptography- Part 3. Or visit this Wikipedia page.

Question 12

Define:

Known Plain Text Attacks

Answer 12

A known plain text attack occurs when adversaries possess the original plaintext along with its encrypted form, leveraging this information to uncover cryptographic keys or vulnerabilities.

By comparing input-output pairs, attackers identify patterns or flaws in the encryption algorithm, helping them predict or reverse-engineer future encryptions. Weak ciphers and poor key management amplify such risks. Defense strategies include using strong, modern encryption standards, regularly rotating keys, and validating cryptographic implementations. Minimizing data exposure and applying best practices reduce susceptibility to known plain text attacks.

For more information, visit this Wikipedia page.

Question 13

Define:

Known-Plaintext Attack

Answer 13

A cryptanalysis attack where the attacker has both the plaintext and ciphertext, potentially revealing the encryption key.

A known-plaintext attack is a method of cryptanalysis where the attacker has access to both the plaintext (unencrypted message) and its corresponding ciphertext (encrypted message). It is used to exploit weaknesses in encryption algorithms by analyzing how the plaintext is transformed into ciphertext, with the aim of discovering the encryption key. Examples include attacks on historical ciphers like the Vigenère cipher.

For more information, view this lecture on Attacks on Our Cryptography- Part 2. Or visit this Wikipedia page.

Question 14

Define:

Kubernetes

Answer 14

Kubernetes is an open-source container orchestration platform that automates application deployment, scaling, and management across clusters of hosts.

Developed by Google, Kubernetes schedules and distributes containers, handling load balancing, health monitoring, and self-healing. It uses a declarative model where operators define desired states in configuration files—Kubernetes continuously works to achieve those states. Popular features include rolling updates, secrets management, and persistent storage orchestration. Security considerations encompass network policies, resource quotas, role-based access control, and container image scanning. Kubernetes underpins many microservices and DevOps strategies, enabling efficient, scalable containerized environments.

For more information, visit this Wikipedia page.

Question 15

Define:

KVMs

(Keyboard, Video, and Mouse Switches)

Answer 15

Devices that allow control of multiple computers with one set of peripherals, critical for managing secure workstations.

Hardware devices that allow users to control multiple computers from one set of keyboard, monitor, and mouse. While they are not inherently security devices, their use can have significant security implications. For example, they can reduce the number of peripheral devices, thus limiting potential entry points for hardware keyloggers. However, they also need to be secured properly as they can be a point of vulnerability, potentially allowing an attacker with physical access to switch between and gain control of connected systems.

For more information, view this lecture on Hardware Architecture- Part 1. Or visit this Wikipedia page.

Question 16

Define:

Lattice Security Model

Answer 16

A security model using a lattice structure for hierarchical access control in computing environments.

A security model that defines access to resources based on a lattice-like structure of security levels and clearance rules. It is used to enforce hierarchical access control and prevent unauthorized access to sensitive information. Examples of the lattice security model include the Bell-LaPadula and Biba models.

For more information, view this lecture on Security Models and Concepts - Part 1. Or visit this Wikipedia page.

Question 17

Define:

Legacy System

Answer 17

Outdated technology still in operation, often vulnerable to cyber threats due to lack of updates or support.

A legacy system is an outdated computing system or application that is still in use despite being surpassed by newer technologies. These systems often lack support and modern security features, making them vulnerable to cyber threats. Security strategies for legacy systems may include isolated environments, stringent access controls, and regular risk assessments until they can be safely upgraded or replaced.

For more information, view this lecture on Hardware Architecture- Part 1. Or visit this Wikipedia page.

Question 18

Define:

Lifecycle of Cryptography

Answer 18

The comprehensive process of managing cryptographic systems and keys, from development to decommissioning.

The process of developing, implementing, and managing cryptographic systems for information security. It involves selecting the appropriate cryptographic algorithms and key sizes, generating and securely storing keys, and regularly updating and retiring cryptographic systems. It is used in various industries to protect sensitive information such as financial transactions, medical records, and government communications.

For more information, view this lecture on The Encryption We Use Today.

Question 19

Define:

Limit Registers

Answer 19

Hardware components that define the allowable memory access range for processes, safeguarding against buffer overflows.

Limit registers in computer architecture are used to define the boundaries of the memory space that a process or application is permitted to access. They help protect the system by preventing a program from reading from or writing to memory outside its allocated area, thereby avoiding potential security breaches like buffer overflows.

Question 20

Define:

Linear Cryptanalysis

Answer 20

A method to compromise encryption algorithms by analyzing linear approximations of block ciphers.

Linear cryptanalysis is a method for breaking symmetric cryptographic algorithms by creating linear approximations to describe the behavior of the block cipher. By analyzing input and output bits, cryptanalysts can find correlations that may lead to uncovering the secret key. It is a powerful tool for evaluating the strength of encryption algorithms.

For more information, view this lecture on Attacks on Our Cryptography- Part 3. Or visit this Wikipedia page.

Question 21

Define:

Linux

Answer 21

Linux is an open-source operating system kernel that powers a wide array of distributions, highly regarded for its security, modularity, and community-driven development.

Created by Linus Torvalds in 1991, Linux offers a robust, scalable environment for servers, desktops, and embedded devices. Popular distributions, such as Ubuntu and Red Hat, build upon the Linux kernel with various tools and package managers. Its permissive licensing encourages innovation and transparency, letting developers inspect and modify source code. With inherent multiuser permissions, frequent patches, and a strong ecosystem, Linux provides a secure foundation for countless applications.

For more information, view this lecture on Secure Operating Systems and Software Architecture. Or visit this Wikipedia page.

Question 22

Define:

Locks

Answer 22

Mechanisms that restrict access to physical or digital assets.

Locks are devices or software measures designed to restrict unauthorized access to secured areas or data. In physical security, locks protect buildings and rooms, while in digital systems, similar controls secure data and network resources. Effective locking mechanisms are essential for preventing unauthorized entry and ensuring that both tangible and intangible assets remain protected against potential breaches.

For more information, view this lecture on Physical Security- Part 3. Or visit this Wikipedia page.

Question 23

Define:

Logic Bomb

Answer 23

Malicious code activated under specific conditions to disrupt systems or steal data.

A type of malicious code that is designed to trigger a specific action when certain conditions are met. It is used to disrupt operations, steal data, or cause damage to a system. Examples include triggering a data deletion when a user logs off, activating a ransomware attack on a specific date, or sending confidential information to a remote server.

For more information, view this lecture on Malware- Part 2. Or visit this Wikipedia page.

Question 24

Define:

Logical Cloud Isolation

Answer 24

Separating cloud environments to prevent access between them and protect data.

The process of separating different parts of a cloud environment, such as different applications or customers, to ensure that they are isolated from each other. It is used to enhance security and prevent unauthorized access to sensitive data. For example, a cloud provider may use logical cloud isolation to prevent one customer’s data from being accessed by another customer.

Question 25

# Define: Low Granularity in Data

Answer 25

Data with a high-level view, providing less detail but useful for general analysis. ## Footnote Low granularity in data refers to a high-level or summary view of data where the information is aggregated or less detailed. It can be beneficial for analyzing overall trends and patterns but may lack the finer details required for in-depth analysis. Examples of low granularity could include annual revenue figures or total page views on a website, as opposed to transaction-level or page-level details.

Question 26

# Define: LUN | (Logical Unit Number)

Answer 26

An identifier used to designate individual storage units within a SAN environment. ## Footnote A Logical Unit Number (LUN) is a unique identifier assigned to individual logical storage units within a storage area network. It allows administrators to manage, allocate, and secure specific partitions or volumes on physical storage devices. By clearly delineating data segments, LUNs facilitate efficient storage utilization, reliable data access, and streamlined backup and recovery processes in complex storage architectures. *For more information, view this lecture on [SAN and VoIP protocols](https://courses.thorteaches.com/courses/take/cissp/lessons/19177558-san-and-voip-protocols). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Logical_unit_number).*

Question 27

# Define: MacOS

Answer 27

MacOS is Apple’s proprietary operating system for Macintosh computers, known for a graphical user interface, integrated ecosystem, and focus on usability and security. ## Footnote Based on a Unix foundation, MacOS incorporates features like Gatekeeper and System Integrity Protection, limiting unauthorized code execution and safeguarding system files. Regular updates patch vulnerabilities and align the OS with Apple’s hardware optimizations. Though historically less targeted by malware compared to Windows, MacOS faces rising security challenges as adoption grows. Users benefit from a polished environment but must remain vigilant with secure configurations. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/MacOS).*

Question 28

# Define: Macro Virus

Answer 28

Malware spread through infected document macros, automating malicious tasks. ## Footnote A type of malware that is spread through infected documents or files that contain macro commands. It is used to automate actions and perform malicious tasks, such as deleting files or stealing sensitive information. Examples include the Melissa virus, which spread through email attachments, and the WannaCry ransomware, which used macros to encrypt victims' files. *For more information, view this lecture on [Malware- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/18684054-malware-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Macro_virus).*

Question 29

# Define: Mainframe

Answer 29

A powerful, large-capacity computer optimized for data processing and enterprise-level applications. ## Footnote A large, powerful computer designed for high-volume data processing and transaction processing. It is used in industries such as finance, telecommunications, and government to handle large amounts of data and support multiple users simultaneously. Examples include IBM's z/OS operating system and the CICS transaction processing system. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Mainframe_computer).*

Question 30

# Define: Malware

Answer 30

Any software designed to harm computer systems or data, such as viruses and ransomware. ## Footnote A term used to describe any software that is designed to cause harm to a computer or network. It is used to refer to a variety of malicious software, such as viruses, worms, ransomware, and spyware. Examples include the WannaCry ransomware, the Mirai botnet, and the Stuxnet worm. *For more information, view this lecture on [Malware- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/18684054-malware-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Malware).*

Question 31

# Define: Malware Inspection

Answer 31

Examining files or systems for malicious software to ensure system integrity and security. ## Footnote The process of examining files or systems for the presence of malicious software. It can involve a range of techniques, from simple signature-based detection (matching files against a database of known malware) to more sophisticated behavioral or heuristic analysis (looking for abnormal behavior or characteristics that suggest malware). Regular and thorough malware inspections are key for maintaining system health and integrity. *For more information, view this lecture on [Malware- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/18684054-malware-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Malware).*

Question 32

# Define: Man-in-the-Middle Attack | (MitM)

Answer 32

An attack where a third party intercepts and potentially alters communication between two parties. ## Footnote A form of eavesdropping where communication between two users is monitored and modified by an unauthorized party. Typically, the attacker will intercept the traffic between the two targets, making them believe they are talking directly to each other over a private connection when, in fact, the entire conversation is being controlled by the attacker. *For more information, view this lecture on [Attacks on our cryptography- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19149711-attacks-on-our-cryptography-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Man-in-the-middle_attack).*

Question 33

# Define: Mantrap

Answer 33

A physical security system with interlocking doors to control individual access to secure areas. ## Footnote A physical security access control system comprising a small space having two sets of interlocking doors such that the first set of doors must close before the second set opens. Mantraps ensure that only one person can pass through at a time, and they provide an effective mechanism for controlling and monitoring access to secure environments. *For more information, view this lecture on [Physical security- Part 4](https://courses.thorteaches.com/courses/take/cissp/lessons/19632100-physical-security-part-4). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Mantrap_(access_control)).*

Question 34

# Define: Master Boot Record | (MBR)

Answer 34

The first sector of a storage device, storing the bootloader for the operating system. ## Footnote The first sector of a hard drive that contains the bootloader program and the partition table. It is used to boot the operating system on a computer. Examples -A computer's BIOS uses the MBR to boot the operating system, a bootable USB drive contains an MBR, and a disk repair utility can fix a corrupted MBR. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Master_boot_record).*

Question 35

# Define: Mathematical Attack

Answer 35

An attempt to break encryption by exploiting weaknesses in the encryption's mathematical algorithms. ## Footnote A method used to decipher encrypted data by exploiting weaknesses in the mathematical algorithms used in the encryption process. This method relies on computational techniques and mathematical theories, such as factoring large numbers or calculating discrete logarithms, to reverse-engineer or break the encryption algorithm and gain access to the encrypted data.

Question 36

# Define: MD6 | (Message Digest 6)

Answer 36

A cryptographic hash function designed to produce a fixed-size output from input data. ## Footnote MD6 is a cryptographic hash function that transforms variable-length input data into a fixed-size, collision-resistant hash value. Developed as a candidate for secure hash standards, it aims to provide strong cryptographic security, though its performance and adoption have been subject to extensive analysis and debate within the security community. *For more information, view this lecture on [Hashing- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19149697-hashing-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/MD6).*

Question 37

# Define: Meet-in-the-Middle Attack

Answer 37

A cryptanalysis technique using a two-front approach to uncover encryption keys, compromising ciphers. ## Footnote A cryptanalytic technique where the attacker attempts to break a cipher by essentially meeting in the middle of the encryption process. The attacker independently computes both the plaintext-to-ciphertext and ciphertext-to-plaintext transformations for a range of values and then matches them to uncover the cryptographic key. This type of attack often requires significant computational resources, but it can effectively reduce the security of a cipher. *For more information, view this lecture on [Attacks on our cryptography- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/19423030-attacks-on-our-cryptography-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Meet-in-the-middle_attack).*

Question 38

# Define: Memory Cards

Answer 38

Removable storage devices for saving and transporting data files, used in cameras, phones, and other electronics. ## Footnote Portable storage devices used for saving, transferring, and transporting data files. Memory cards are commonly used in digital cameras, mobile phones, and other electronic devices for expandable and removable data storage solutions. *For more information, view this lecture on [Asset tracking and hardware hardening](https://courses.thorteaches.com/courses/take/cissp/lessons/20679155-asset-tracking-and-hardware-hardening). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Memory_card).*

Question 39

# Define: Memory Protection

Answer 39

A method preventing a process from accessing memory outside specified limits, safeguarding system stability. ## Footnote A method used to prevent processes from accessing memory outside their own address space. This isolation mechanism prevents a faulty or malicious process from interfering with another process or the operating system, effectively protecting against unauthorized access or corruption of memory content and thereby maintaining system stability and security. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Memory_protection).*

Question 40

# Define: Merkle Tree

Answer 40

A tree-like structure using cryptographic hashes to securely and efficiently verify large data structures' content. ## Footnote A Merkle tree, named after Ralph Merkle, is a data structure in cryptography and computer science that consists of a hierarchical series of cryptographic hashes. Each non-leaf node is a hash of its respective children, and the hashes are organized into a binary tree. Merkle trees are used to efficiently and securely verify the contents of large data structures, such as the blocks in a blockchain, where they help confirm the integrity of transaction data. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Merkle_tree).*

Question 41

# Define: Message Authentication Code | (MAC)

Answer 41

A short string confirming message integrity and authenticity, generated by a secret key and a hash function. ## Footnote A Message Authentication Code (MAC) is a short string of characters that is used to verify the integrity and authenticity of a message. It is generated by applying a cryptographic hash function to the message and a secret key shared by the sender and intended receiver. A MAC helps ensure that a message has not been altered during transmission and confirms that it came from the authentic sender. *For more information, view this lecture on [MAC, HMAC, SSL, and TLS](https://courses.thorteaches.com/courses/take/cissp/lessons/19149773-mac-hmac-ssl-and-tls). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Message_authentication_code).*

Question 42

# Define: Message Digest

Answer 42

A unique value generated from data by a hash function, used for data integrity and authentication processes. ## Footnote A short, fixed-length value that is generated from a longer message by a cryptographic hashing algorithm. It is used to verify the integrity of the message and to provide authentication. Examples of message digests include SHA-256 and MD5. *For more information, view this lecture on [Hashing- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19149697-hashing-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Cryptographic_hash_function#Verifying_the_integrity_of_messages_and_files).*

Question 43

# Define: Message Digest 5 | (MD5)

Answer 43

A hash function producing a unique 128-bit hash value, used for data integrity checks, now deemed insecure due to vulnerability to collisions. ## Footnote A widely-used cryptographic hash function that produces a 128-bit (16-byte) hash value from input data. It's commonly used to verify data integrity. However, MD5 is considered to be broken and unsuitable for further use as it's vulnerable to hash collisions, where different inputs produce the same output hash. *For more information, view this lecture on [Hashing- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19149697-hashing-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/MD5).*

Question 44

# Define: Metadata-Based Discovery

Answer 44

Analyzing data descriptors to gain insights about stored information without accessing the data directly. ## Footnote Metadata-based discovery involves analyzing data descriptors to gain insights about stored information without accessing the data itself. It is a method used in cybersecurity to quickly assess system configurations, data usage, and changes over time, aiding in vulnerability assessments and security monitoring. For instance, metadata could reveal the creation date of files, their last access times, and modifications, which is beneficial in incident investigations.

Question 45

# Define: Microkernel Architecture

Answer 45

A computing architecture utilizing a minimal kernel for basic functions with additional services implemented in separate modules, enhancing security and modularity. ## Footnote A computer architecture that uses a small, highly modular kernel to provide basic services, such as memory management and task scheduling. It is used in operating systems to improve performance and security by limiting the scope of the kernel. Examples include Mach and QNX. *For more information, view this lecture on [Secure operating systems and software architecture](https://courses.thorteaches.com/courses/take/cissp/lessons/18591315-secure-operating-systems-and-software-architecture). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Microkernel).*

Question 46

# Define: Microsoft Certificate Services

Answer 46

A Windows service that issues and manages digital certificates for secure communications. ## Footnote Microsoft Certificate Services provides a public key infrastructure (PKI) within Windows environments, facilitating the issuance, management, and revocation of digital certificates. This service underpins secure communication, encryption, and authentication protocols, ensuring data integrity and establishing trust across enterprise networks and applications. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Active_Directory#Certificate_Services).*

Question 47

# Define: Microwave Sensors

Answer 47

Microwave sensors emit high-frequency radio waves to detect motion or changes in the environment, commonly used in intrusion alarms and automated doors. ## Footnote When an object disrupts the sensor’s reflected signal, the device interprets it as movement, triggering a response—like opening a door or sounding an alarm. Unlike passive infrared sensors, microwave technology can penetrate non-metallic objects, offering broader coverage. However, they may be prone to false triggers in environments with frequent radio interference. Careful calibration and placement ensure reliable, discrete motion detection. *For more information, view this lecture on [Physical security- Part 5](https://courses.thorteaches.com/courses/take/cissp/lessons/19149815-physical-security-part-5). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Motion_detector#Microwave).*

Question 48

# Define: Mobile Device

Answer 48

A portable computing device like a smartphone, providing connectivity and a range of functionalities. ## Footnote A portable computing device such as a smartphone or tablet that provides a wide range of functionalities including voice communication, internet connectivity, and mobile applications. The ubiquity of mobile devices has significantly influenced communication, work, and entertainment. *For more information, view this lecture on [Mobile device security](https://courses.thorteaches.com/courses/take/cissp/lessons/19148750-mobile-device-security). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Mobile_device).*

Question 49

# Define: Mobile Device Management | (MDM)

Answer 49

Software managing and securing mobile devices within an organization, crucial for protecting data. ## Footnote A type of security software that is used by an organization to monitor, manage, and secure employees' mobile devices that are deployed across multiple operating systems and service providers. These devices can be used both in the office and outside the office as part of the organization's network infrastructure. MDM tools can enforce policies for data security, conduct remote management like device wiping in case of loss or theft, and offer inventory management functions. *For more information, view this lecture on [Mobile Device Security](https://courses.thorteaches.com/courses/take/cissp/lessons/19148750-mobile-device-security). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Mobile_device_management).*

Question 50

# Define: Modbus

Answer 50

A communication protocol for industrial automation, allowing devices to exchange data and control commands. ## Footnote A communication protocol used in industrial automation systems to allow devices to communicate with each other and exchange data. It is commonly used in the manufacturing and energy industries to control and monitor equipment. Examples include using Modbus to control the temperature of a furnace in a factory or the flow of oil in a refinery. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Modbus).*

Question 51

# Define: Mode of Operation

Answer 51

How a cryptographic algorithm is applied to data, impacting encryption and data security processes. ## Footnote The way in which a cryptographic algorithm is used to protect data. It determines how the algorithm processes the data and can have a significant impact on the security of the resulting ciphertext. Examples include electronic codebook (ECB) mode, cipher block chaining (CBC) mode, and counter (CTR) mode. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation).*

Question 52

# Define: Monoalphabetic

Answer 52

A substitution cipher using a fixed one-to-one letter mapping. ## Footnote A monoalphabetic cipher encrypts text by consistently substituting each letter of the plaintext with another fixed letter. Despite its historical significance and simplicity, it is vulnerable to frequency analysis attacks due to its static substitution pattern, making it unsuitable for securing sensitive communications in modern applications. *For more information, view this lecture on [Introduction to Cryptography- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/19121903-introduction-to-cryptography-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Substitution_cipher).*

Question 53

# Define: Monolithic Operating System Architecture

Answer 53

A system setup where the operating system components are combined into a single unit, potentially less secure due to crash vulnerability. ## Footnote A monolithic operating system architecture is one where the entire operating system, including the kernel, device drivers, and system services, operates in a single memory space. This traditional architecture can offer fast performance due to its direct access to system hardware, but it may be less flexible and more vulnerable to system-wide crashes or security breaches if a single component fails or is compromised. *For more information, view this lecture on [Secure operating systems and software architecture](https://courses.thorteaches.com/courses/take/cissp/lessons/18591315-secure-operating-systems-and-software-architecture). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Monolithic_kernel).*

Question 54

# Define: Motion Detectors

Answer 54

Devices that sense movement to trigger alerts or automate responses. ## Footnote Motion Detectors are sensors that detect physical movement within a defined area, triggering alarms or initiating automated actions. Commonly used in security systems, they rely on technologies such as infrared, ultrasonic, or microwave sensing to capture movement. Their application in both commercial and residential settings enhances safety by providing real-time monitoring and rapid responses to unauthorized activity or environmental changes. *For more information, view this lecture on [Physical security- Part 5](https://courses.thorteaches.com/courses/take/cissp/lessons/19149815-physical-security-part-5). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Motion_detector).*

Question 55

# Define: Multipart or Multipartite Viruses

Answer 55

Malware that can infect systems multiple ways, ensuring its execution at every system boot. ## Footnote A type of malicious software that can infect systems in multiple ways, not limiting itself to a single method. They might infect both program files and system sectors simultaneously, ensuring their execution at every system startup. This dual-mode infection capability makes them particularly hard to remove, as they can re-infect parts of the system that have already been cleaned. *For more information, view this lecture on [Malware- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/18684054-malware-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Computer_virus).*

Question 56

# Define: Multi-Security Level | (MSL)

Answer 56

Systems designed to handle data of varied security levels, maintaining data segregation and control. ## Footnote Systems that are designed to handle data of varying security levels simultaneously. These systems need to ensure the proper separation and access control between data categories to prevent unauthorized access or data leaks. These are particularly important in environments that manage classified, sensitive, or proprietary information.

Question 57

# Define: Multitasking

Answer 57

An operating system feature allowing the concurrent execution of multiple tasks, improving user productivity. ## Footnote The ability of an operating system to execute multiple tasks concurrently. It involves managing system resources among different applications or processes to enhance productivity and efficiency. While users may perceive their tasks as running in parallel, the operating system rapidly switches between tasks to give the appearance of simultaneous execution while ensuring each task receives the required resources. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Computer_multitasking).*

Question 58

# Define: Multitenancy

Answer 58

Multitenancy is a software architecture where multiple users or organizations (tenants) share a single application instance, typically in a cloud environment, while keeping data segregated. ## Footnote This approach optimizes resource utilization and reduces costs, as underlying infrastructure is centrally managed. Each tenant experiences a customized view, isolating their information to maintain privacy. Proper security measures—like tenant-aware access controls—prevent cross-tenant data leaks. Multitenancy underpins many SaaS offerings, enabling providers to scale efficiently while offering potentially lower costs, frequent updates, and streamlined support. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Multitenancy).*

Question 59

# Define: Multitenant Environments

Answer 59

Architectures where one application instance serves multiple tenant organizations, requiring data privacy management. ## Footnote A software architecture where a single instance of an application serves multiple user organizations or tenants. Multitenancy enhances resource efficiency and cost-effectiveness but requires careful data segregation to maintain security and privacy. *For more information, view this lecture on [Virtualization, Cloud, and Distributed Computing - Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/18591376-virtualization-cloud-and-distributed-computing-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Multitenancy).*

Question 60

# Define: NIST SP 800-133

Answer 60

Guidance on cryptographic key generation to ensure the security of information systems. ## Footnote NIST Special Publication 800-133 provides guidance on generating cryptographic keys, which are used in many security protocols to provide confidentiality, integrity, and authentication. The guidance includes the provision of secure random number generators and other technical details necessary for secure key generation, aiding organizations in ensuring the adequacy of the cryptographic keys that protect their data. *For more information, visit this [Wikipedia page](https://csrc.nist.gov/pubs/sp/800/133/r2/final).*

Question 61

# Define: NIST SP 800-145

Answer 61

A definition and understanding of cloud computing models and services for organizational adoption. ## Footnote NIST Special Publication 800-145 offers a concise definition and comprehensive understanding of cloud computing, a model that allows ubiquitous, convenient, and on-demand network access to a shared pool of configurable computing resources. It defines essential characteristics, service models, and deployment models for cloud computing, providing the foundations for its adoption and helping organizations understand and navigate the landscape of cloud services. *For more information, visit this [Wikipedia page](https://csrc.nist.gov/pubs/sp/800/145/final).*

Question 62

# Define: NIST SP 800-160

Answer 62

Principles for engineering secure systems, emphasizing security throughout the system lifecycle. ## Footnote NIST Special Publication 800-160 provides principles and practices for engineering secure and reliable systems, emphasizing the need for security and privacy to be considered throughout a system's life cycle. The document promotes a holistic and risk-based approach to enhance the resilience of systems and networks. Its focus is on the integration of security into systems engineering to create systems that are secure by design, effectively managing and mitigating risk from the inception of a system's life cycle. *For more information, visit this [Wikipedia page](https://csrc.nist.gov/pubs/sp/800/160/v1/upd2/final).*

Question 63

# Define: NIST SP 800-33

Answer 63

Guidelines on underlying technical models for IT security, outlining necessary security services and mechanisms. ## Footnote NIST Special Publication 800-33, titled "Underlying Technical Models for Information Technology Security," is a document from the National Institute of Standards and Technology (NIST) that provides guidance on the technical foundation of IT security. It outlines models that describe the necessary security services and the corresponding security mechanisms required to provide those services. The publication is aimed at helping organizations understand the principles behind building secure IT systems by addressing aspects such as confidentiality, integrity, authentication, and non-repudiation. SP 800-33 has been superseded by other documents in the NIST SP 800 series that provide updated and detailed guidance on securing information technology systems. *For more information, visit this [Wikipedia page](https://csrc.nist.gov/pubs/sp/800/33/final).*

Question 64

# Define: NIST SP 800-82

Answer 64

NIST Special Publication 800-82 Revision 2 provides guidelines for securing Industrial Control Systems (ICS), such as SCADA systems, DCS, and PLCs. ## Footnote NIST Special Publication 800-82 offers guidance on securing industrial control systems, including Supervisory Control and Data Acquisition (SCADA) systems, Distributed Control Systems (DCS), and other control system configurations. The guidance aims to help protect these systems from potential threats and reduce risks associated with the operational technology environment. *For more information, visit this [Wikipedia page](https://csrc.nist.gov/pubs/sp/800/82/r3/final).*

Question 65

# Define: Nonce

Answer 65

A number used once in communication protocols to ensure data freshness and prevent replay attacks. ## Footnote A randomly or pseudo-randomly generated number that is used only once in a communication protocol. They are often employed to ensure data freshness and to prevent replay attacks where an attacker might attempt to replay a previous communication or transaction, leading to potential data breaches or fraudulent transactions. *For more information, view this lecture on [Hashing- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/19314170-hashing-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Cryptographic_nonce).*

Question 66

# Define: Non-Conductive, Non-Toxic Liquid Suppressants | (NOVEC)

Answer 66

Fire suppression solutions for environments with electronic equipment, such as data centers. ## Footnote Non-Conductive, Non-Toxic Liquid Suppressants, marketed under the brand name NOVEC, are fire suppression solutions designed for use in environments with sensitive electronic equipment, such as data centers. These suppressants extinguish fires without causing damage to hardware or leaving harmful residues, ensuring the safety of both the equipment and the facility. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Fire_extinguisher#Clean_agents).*

Question 67

# Define: Noninterference Model

Answer 67

A security model ensuring higher-level actions do not affect lower security levels in an information system. ## Footnote The Noninterference Model is a formal security model designed to ensure that actions at a higher security level do not affect or interfere with the lower security levels within an information system. It's used to enforce confidentiality policies by preventing the flow of information from higher to lower security domains. *For more information, view this lecture on [Security models and concepts- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/18591282-security-models-and-concepts-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Non-interference_(security)).*

Question 68

# Define: Non-Repudiation

Answer 68

A property ensuring someone cannot deny the validity of their digital actions or documents. ## Footnote A property of systems that provides assurance that someone cannot deny the validity of something. Typically used in digital security, it provides proof of the origin or delivery of data to protect the sender against false denial by the recipient that the data has been received or to protect the recipient against false denial by the sender that the data has been sent. *For more information, view this lecture on [Digital signatures](https://courses.thorteaches.com/courses/take/cissp/lessons/19149728-digital-signatures) and [Accountability](https://courses.thorteaches.com/courses/take/cissp/lessons/19179221-accountability). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Non-repudiation#In_digital_security).*

Question 69

# Define: N-Tier Architecture

Answer 69

A system architecture with separate layers for presentation, application, and data management. ## Footnote A client-server architecture where the presentation, application processing, and data management functions are logically separated into separate layers or tiers. This separation allows developers to modify or add a specific layer rather than reworking the entire application, improving scalability and performance. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Multitier_architecture).*

Question 70

# Define: Obfuscation

Answer 70

Intentionally making data difficult to understand to hide information or protect sensitive data. ## Footnote The practice of making something difficult to understand or interpret intentionally designed to conceal or hide information. In the context of data security, obfuscation is often used to protect sensitive data, such as code, by transforming it into an equivalent form that is harder to understand, thereby limiting potential exposure to unauthorized parties. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Obfuscation).*

Question 71

# Define: OEM | (Original Equipment Manufacturer)

Answer 71

An OEM designs and produces hardware or software components that are later rebranded or integrated by another company before reaching end-users. ## Footnote Examples include motherboard makers, firmware developers, or even software libraries packaged within larger solutions. OEM partnerships streamline development cycles, leverage specialized expertise, and reduce costs for final product assembly. Security considerations arise if OEM-supplied components contain undisclosed vulnerabilities. Clear supply chain oversight, patch management, and contractual obligations help ensure OEM elements meet quality and security standards. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Original_equipment_manufacturer).*

Question 72

# Define: On-Demand Computing

Answer 72

On-demand computing refers to delivering IT resources—like processing power or software—whenever needed, often billed per usage, typical of cloud service models. ## Footnote This approach provides elastic scaling, matching capacity to real-time demand without requiring extensive in-house infrastructure. By leveraging remote data centers, organizations cut operational costs and maintenance overhead. On-demand computing supports agile development, letting teams experiment and deploy quickly. Yet transparency in pricing, robust security protections, and continuity planning remain vital. Adopting on-demand computing fosters flexibility and competitive advantage. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Cloud_computing).*

Question 73

# Define: One-Time Cryptosystem

Answer 73

A cryptographic system using unique keys for each message or session. ## Footnote A cryptographic system that uses a different key for each message or communication. It is used to provide high-level security for sensitive information, as the key cannot be reused or derived from previous messages. Examples include the one-time pad cipher and the Diffie-Hellman key exchange.

Question 74

# Define: One-Time Pad

Answer 74

An encryption method using a random key only once, providing high security. ## Footnote A symmetric-key cipher that uses a random key that is as long as the message and is used only once. It is considered the most secure encryption method, as the key cannot be derived from the ciphertext. Examples include using a one-time pad to encrypt classified documents or to secure communication between two parties. *For more information, view this lecture on [The history of Cryptography- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/19215103-the-history-of-cryptography-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/One-time_pad).*

Question 75

# Define: One-Way Function

Answer 75

A function that is easy to compute forward but hard to reverse, fundamental in cryptographic hashing operations. ## Footnote In cryptography, a one-way function is a function that is easy to compute in the forward direction but significantly harder to reverse or invert the computation. It is fundamental in various cryptographic operations such as hashing, where the one-way property ensures that even if the output is known, it remains infeasible to recover the original input. The one-way function underpins the concept of cryptographic hashes used to secure passwords and other sensitive data. *For more information, view this lecture on [Hashing- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19149697-hashing-part-1) and [Hashing- Part 2](https://courses.thorteaches.com/courses/take/cissp).*

Question 76

# Define: One-Way Hash

Answer 76

A cryptographic function that produces a unique fixed-size output, designed to be irreversible and secure. ## Footnote A type of cryptographic hash function that takes an input and produces a fixed-size output, called a hash value or digest. It is designed to be one-way, meaning that it is computationally infeasible to determine the original input from the hash value. Examples include the SHA-256 and MD5 algorithms. *For more information, view this lecture on [Hashing- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19149697-hashing-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/One-way_function).*

Question 77

# Define: On-Premises | (On-Prem)

Answer 77

Hosting solutions within an organization's physical infrastructure, offering more control over data and systems compared to cloud services. ## Footnote The deployment and hosting of solutions directly within an organization's physical infrastructure. Unlike cloud services, which are hosted by a third party and accessed over the Internet, on-prem solutions are managed in-house. This typically provides the organization greater control over its data and systems but also requires the organization to handle its own maintenance, upgrades, and security. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/On-premises_software).*

Question 78

# Define: Open System

Answer 78

A computing model promoting interoperability and user choice, typically through open standards or source code. ## Footnote A model of computing systems that provides some form of openness, such as open standards, interfaces, or source code. This openness promotes interoperability, portability, and user choice and allows users and developers to have significant influence over how the system operates. Open systems are often contrasted with closed systems, which are controlled by a single entity and where the inner workings of the system are not made available to users or developers. *For more information, view this lecture on [Secure system design concepts](https://courses.thorteaches.com/courses/take/cissp/lessons/18591293-secure-system-design-concepts). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Open_system_(computing)).*

Question 79

# Define: Operating System | (OS)

Answer 79

Core software managing a computer's hardware and software resources, providing services for various applications. ## Footnote The primary software that manages all the hardware and other software on a computer. It performs a variety of functions, including managing memory, processing tasks, accessing the hard drive, interpreting commands from a keyboard or mouse, and sending output to a display screen. *For more information, view this lecture on [Secure operating systems and software architecture](https://courses.thorteaches.com/courses/take/cissp/lessons/18591315-secure-operating-systems-and-software-architecture). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Operating_system).*

Question 80

# Define: OS Hardening

Answer 80

The process of securing an operating system by reducing its attack surface, such as disabling unnecessary services and applying security settings. ## Footnote Operating system (OS) hardening is the practice of securing an OS by reducing its surface area of vulnerability, which includes the disabling of unnecessary services, protecting against unauthorized access, applying patches, and enforcing the principle of least privilege. It's a crucial step during initial system setup and an ongoing policy in maintaining robust security postures, as it helps create a more secure environment that is less susceptible to cyber threats. *For more information, view this lecture on [Asset tracking and hardware hardening](https://courses.thorteaches.com/courses/take/cissp/lessons/20679155-asset-tracking-and-hardware-hardening). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Hardening_(computing)).*

Question 81

# Define: Overt Channel

Answer 81

A standard communication path within a system used for intended data transfer, monitored for security. ## Footnote An overt channel is a standard, open, and legitimate path for communication within a computer system or network. It is utilized to transfer data as intended by its design and is often monitored for security purposes. This term should not be confused with a covert channel, which is a pathway that is used for unauthorized transmission of information within a computer system. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Overt_channel).*

Question 82

# Define: Panic Bar

Answer 82

A door mechanism designed for quick exit in emergency situations. ## Footnote A Panic Bar is a type of door hardware installed on emergency exits that enables quick and effortless egress during crises. Engineered for high-traffic environments, it allows occupants to exit buildings rapidly while simultaneously preventing intrusion from the outside. Panic Bars are critical components in ensuring building safety and compliance with fire and emergency egress regulations. *For more information, view this lecture on [Physical security- Part 5](https://courses.thorteaches.com/courses/take/cissp/lessons/19149815-physical-security-part-5). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Crash_bar).*

Question 83

# Define: Pan-Tilt-Zoom | (PTZ)

Answer 83

Camera features allowing remote control over direction and zoom, used in security surveillance to cover wide areas. ## Footnote A type of camera distinguished by its capability to remotely directional and zoom control. In a security context, PTZ cameras are often used for surveillance, allowing operators to monitor large areas with a single camera. The pan feature allows the camera to move left or right, tilt moves up and down, and zoom focuses the lens closer or further from an area of interest. *For more information, view this lecture on [Physical security- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/19149796-physical-security-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Pan–tilt–zoom_camera).*

Question 84

# Define: Partitioned Security Mode

Answer 84

A method of improving security by isolating system parts into distinct compartments with specific access controls. ## Footnote A security technique that divides a system into smaller, isolated compartments or domains to improve its security and control access. It is used to prevent unauthorized access to sensitive data and resources. Examples include role-based access control and security domains. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Partitioned_security_mode).*

Question 85

# Define: Partitioning

Answer 85

Dividing a storage device into separate sections, each acting as an independent disk, for data management and organization. ## Footnote The division of a computer's hard drive or storage space into separate, discrete sections, each functioning as an independent disk, to optimize system performance and data management. Partitioning can also refer to dividing databases, memory, and other resources for better organization and security. *For more information, view this lecture on [The 3 States of Data (data at rest, data in motion, and data in use)](https://courses.thorteaches.com/courses/take/cissp/lessons/18588257-the-3-states-of-data-data-at-rest-data-in-motion-and-data-in-use). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Partition_(computing)).*

Question 86

# Define: Pass the Hash

Answer 86

An attack method using stolen password hashes to authenticate without plaintext. ## Footnote Pass the Hash is a technique whereby attackers use intercepted cryptographic hash values, instead of the actual passwords, to gain unauthorized access to systems. By exploiting the fact that many systems validate authentication using these hashes, attackers bypass the need to crack the password itself. This approach highlights vulnerabilities in password-based authentication, stressing the need for improved multi-factor and session-based security measures. *For more information, view this lecture on [Attacks on our cryptography- Part 3](https://courses.thorteaches.com/courses/take/cissp/lessons/19423096-attacks-on-our-cryptography-part-3). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Pass-the-hash).*

Question 87

# Define: Pass-the-Hash

Answer 87

An attack method where an attacker uses a hashed user password to gain unauthorized access to a system. ## Footnote A type of exploit where an attacker uses a hashed form of a user's password instead of the actual password to authenticate against a network service. This kind of attack bypasses the need to decrypt or crack the password and takes advantage of the fact that many systems authenticate users by comparing the hash of the provided password with the stored hash. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Pass_the_hash).*

Question 88

# Define: Password Cracking

Answer 88

Attempting to guess or decrypt a user's password, often using methods like brute force or dictionary attacks. ## Footnote The process of attempting to guess or decrypt a password that has been stored or transmitted, often by trying a series of possible passwords until the correct one is found. Various methods are used, including brute force attacks (trying all possible combinations), dictionary attacks (using common words or phrases), and rainbow table attacks (precomputed tables for reversing hash functions). *For more information, view this lecture on [Type 1 authentication - "Something you know" or "Knowledge factors"](https://courses.thorteaches.com/courses/take/cissp/lessons/19178829-type-1-authentication-something-you-know-or-knowledge-factors). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Password_cracking).*

Question 89

# Define: Password Guessing

Answer 89

Trying to gain system access by guessing passwords, often mitigated by enforcing complex password policies. ## Footnote The method where an unauthorized entity tries to gain access to a system by guessing the password. This is usually done through brute force methods (trying all possible combinations) or, more commonly, by using lists of commonly used passwords. Password guessing can be mitigated by enforcing complexity requirements and limiting the number of failed attempts. *For more information, view this lecture on [Type 1 authentication - "Something you know" or "Knowledge factors"](https://courses.thorteaches.com/courses/take/cissp/lessons/19178829-type-1-authentication-something-you-know-or-knowledge-factors). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Password_cracking).*

Question 90

# Define: Password Spraying Password Attacks

Answer 90

These attacks use a small set of common or weak passwords across many user accounts, exploiting the likelihood that some users reuse easily guessable credentials. ## Footnote Unlike brute force focused on one account, spraying avoids quick lockouts by rotating targeted accounts with each password attempt. Attackers often rely on lists like “Password123!” or “Welcome1” to find at least one valid login. Mitigations range from enforcing strong password policies, implementing multi-factor authentication, to detecting anomalous login patterns. Vigilance prevents large-scale breaches via reused or simplistic passwords. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Password_cracking).*

Question 91

# Define: PDUS | (Power Distribution Units)

Answer 91

PDUs are devices used in data centers or server racks to distribute electrical power to multiple equipment, often featuring monitoring and remote management. ## Footnote Besides basic power distribution, modern PDUs track voltage, amperage, and power usage, helping optimize energy consumption. Administrators can remotely cycle outlets, preventing physical site visits to handle equipment resets. Overloading circuits or losing power can severely impact operations, so PDUs contribute to reliable uptime. Proper capacity planning, load balancing, and redundancy reduce single points of failure. *For more information, view this lecture on [Electricity](https://courses.thorteaches.com/courses/take/cissp/lessons/19149858-electricity). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Power_distribution_unit).*

Question 92

# Define: Perimeter Security Controls

Answer 92

Security measures implemented at the edge of a network to protect against unauthorized access. ## Footnote Measures that are implemented at the boundary of a network or system to prevent unauthorized access and protect internal resources. It is used in network security to create a barrier between trusted and untrusted networks and to monitor and control traffic. Examples include firewalls, intrusion detection systems, and network access control. *For more information, view this lecture on [Physical security- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19149785-physical-security-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Perimeter_intrusion_detection).*

Question 93

# Define: Peripherals

Answer 93

External devices connected to a computer to perform various functions like input, output, and storage. ## Footnote These are external devices connected to a computer system, expanding its capabilities. Peripherals include items like keyboards, mice, printers, scanners, and external drives. They enable input, output, and storage functions that are not inherently part of the core computer architecture. *For more information, view this lecture on [Hardware architecture- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/18591300-hardware-architecture-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Peripheral).*

Question 94

# Define: Pervasive Encryption

Answer 94

Extensive use of encryption techniques to secure all data, regardless of its state, against unauthorized access. ## Footnote The widespread use of encryption techniques to secure data and communications at all times, regardless of whether it is being transmitted or stored. It is used in various industries, including healthcare, finance, and government, to protect sensitive information from being accessed or stolen by unauthorized parties. Examples include using encrypted emails to send sensitive documents or using encrypted storage devices to keep confidential data safe. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Pervasive_encryption).*

Question 95

# Define: Physical Controls

Answer 95

Security measures in the environment, such as locks and surveillance, protecting against unauthorized physical access. ## Footnote Security measures that are implemented in the physical environment to protect against unauthorized access to sensitive information. These measures may include locks, barriers, alarms, and surveillance cameras. Physical controls are used to prevent unauthorized individuals from entering a secure area or to detect and deter potential security threats. For example, a building may have locked doors and security cameras to prevent unauthorized access, or a computer may have a password-protected login screen to prevent unauthorized access to its data. *For more information, view this lecture on [Access Control Categories and Types](https://courses.thorteaches.com/courses/take/cissp/lessons/18588072-access-control-categories-and-types). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Physical_security).*

Question 96

# Define: Piggyback Attack

Answer 96

An unauthorized person gains network access by exploiting an authorized user's credentials. ## Footnote A type of cyber-attack that occurs when an unauthorized person or entity gains access to a secure network or system by piggybacking on the credentials of an authorized user. It is often used to bypass security measures and gain access to sensitive data or resources. Examples include an attacker using someone's login credentials to gain access to a company's network, an employee sharing their credentials with a third party, or the attacker following someone else into a building bypassing the card swipe or door lock. *For more information, view this lecture on [Physical security- Part 4](https://courses.thorteaches.com/courses/take/cissp/lessons/19632100-physical-security-part-4). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Tailgating).*

Question 97

# Define: Piggybacking

Answer 97

Unauthorized entry by following someone with access, typically into secure physical areas. ## Footnote The practice of gaining unauthorized access to a restricted area by following someone who has legitimate access. It is often used by individuals who do not have the proper credentials to enter a building or facility but can gain access by following someone who does. It is used in the field of information security to identify and prevent potential security breaches by unauthorized individuals. 3 examples of piggybacking are an individual following an employee into a secure office building, a visitor following a resident into a gated community, and a customer following an employee into a restricted area of a store. *For more information, view this lecture on [Physical security- Part 4](https://courses.thorteaches.com/courses/take/cissp/lessons/19632100-physical-security-part-4). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Tailgating).*

Question 98

# Define: Plain Text or Plaintext

Answer 98

Unencrypted text easily readable without special tools or knowledge. ## Footnote Unencrypted or unformatted text that can be easily read and understood by humans. It is used in cryptography to refer to unencrypted data that can be easily read and understood without the need for special tools or knowledge. Examples include a plain text email message, a plain text document, or a plain text password. *For more information, view this lecture on [Introduction to Cryptography- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19121869-introduction-to-cryptography-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Plaintext).*

Question 99

# Define: Platform as a Service | (PaaS)

Answer 99

Cloud service offering a platform for developing, testing, and deploying applications. ## Footnote A type of cloud computing service that provides a platform for users to develop, test, and deploy applications without the need for infrastructure or infrastructure management. It is used in cloud computing to provide a scalable and flexible environment for developing and deploying applications. Examples include Amazon Web Services Elastic Beanstalk, Google App Engine, and Microsoft Azure. *For more information, view this lecture on [Virtualization, Cloud, and Distributed Computing - Part 3](https://courses.thorteaches.com/courses/take/cissp/lessons/18591378-virtualization-cloud-and-distributed-computing-part-3). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Platform_as_a_service).*

Question 100

# Define: PLD | (Programmable Logic Device)

Answer 100

A digital component programmable to perform custom logic functions. ## Footnote A Programmable Logic Device (PLD) is an integrated circuit that can be configured to perform a variety of logical operations. Its reprogrammable nature offers flexibility for developing custom hardware solutions, rapid prototyping, and adapting to evolving digital system requirements. *For more information, view this lecture on [Memory and Data Remanence](https://courses.thorteaches.com/courses/take/cissp/lessons/18588268-memory-and-data-remanence). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Programmable_logic_device).*

Question 101

# Define: Policy Decision Point

Answer 101

A policy decision point (PDP) is an access control engine that evaluates security policies and decides whether to grant or deny requests based on defined rules. ## Footnote The PDP receives an authorization query, compares context against its security policy set, and returns a response—often permit, deny, or additional steps required. Acting independently from policy enforcement mechanisms, PDPs reduce complexity by centralizing logic. They’re a core element in architectures like XACML, ensuring consistent interpretation of rules across various applications, workflows, and infrastructure components. *For more information, view this lecture on [Policy Decision/Enforcement points, and service account management](https://courses.thorteaches.com/courses/take/cissp/lessons/54399157-new-2024-policy-decision-enforcement-points-and-service-account-management). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Common_Open_Policy_Service).*

Question 102

# Define: Policy Enforcement Point

Answer 102

A policy enforcement point (PEP) intercepts resource requests, forwarding them to the policy decision point and executing the final authorization verdict, such as granting or blocking access. ## Footnote When a client seeks to access an application or data, the PEP triggers a policy check. Upon receiving instructions from the PDP, it either enables or denies entry, logs actions, or enforces additional security measures. This separation of duties standardizes governance across systems. Deploying consistent PEPs within networks helps maintain uniform compliance and security controls. *For more information, view this lecture on [Policy Decision/Enforcement points, and service account management](https://courses.thorteaches.com/courses/take/cissp/lessons/54399157-new-2024-policy-decision-enforcement-points-and-service-account-management). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Common_Open_Policy_Service).*

Question 103

# Define: Polyalphabetic

Answer 103

Polyalphabetic refers to a type of cipher that uses multiple alphabets or shift patterns for encryption, making it more complex than simple substitution ciphers. ## Footnote In classical cryptography examples like the Vigenère cipher, each letter of the plaintext is shifted by a varying sequence of values. This complicates frequency analysis, a key method for cracking monoalphabetic ciphers. Although historically powerful, polyalphabetic ciphers are susceptible to advanced cryptanalysis or known texts. Modern encryption surpasses these methods, but understanding polyalphabetic principles remains vital for cryptographic history and fundamentals. *For more information, view this lecture on [Introduction to Cryptography- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/19121903-introduction-to-cryptography-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Polyalphabetic_cipher).*

Question 104

# Define: Polyinstantiation

Answer 104

Creating multiple instances of data to obscure unauthorized access patterns. ## Footnote Polyinstantiation involves creating multiple, divergent copies of data in a system to prevent unauthorized users from inferring sensitive information. By providing varied responses based on security clearances, this technique thwarts inference attacks and protects data confidentiality, making it an effective strategy in multi-level security environments. *For more information, view this lecture on [Database security](https://courses.thorteaches.com/courses/take/cissp/lessons/19121852-database-security). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Polyinstantiation).*

Question 105

# Define: Polymorphic Virus

Answer 105

Malware that changes its code or signature with each infection to evade detection. ## Footnote A polymorphic virus is a type of malware that can alter its code or signature on each infection, making it difficult for antivirus programs to recognize and remove it using signature-based detection. The virus retains its primary payload but changes how it appears to security programs, thus increasing its chances of spreading without being intercepted. *For more information, view this lecture on [Malware- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/18684054-malware-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Polymorphic_code#Malicious_code).*

Question 106

# Define: POST | (Power-On-Self-Test)

Answer 106

The initial system check performed by a computer upon startup to verify hardware functionality. ## Footnote A term used in computing to refer to the initial boot process of a computer or device. During the POST, the computer or device checks the hardware components and loads the operating system. POST is used to ensure that the computer or device is ready to operate before the user is able to access it. For example, when a user turns on a computer, the POST process will run in the background to check the hardware components and load the operating system. *For more information, view this lecture on [Virtualization, Cloud, and Distributed Computing - Part 4](https://courses.thorteaches.com/courses/take/cissp/lessons/18591381-virtualization-cloud-and-distributed-computing-part-4). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Power-on_self-test).*

Question 107

# Define: Post-Quantum Cryptography | (PQC)

Answer 107

PQC refers to cryptographic algorithms designed to withstand decryption attempts by quantum computers, ensuring long-term data confidentiality despite future quantum advancements. ## Footnote Current public-key algorithms like RSA can theoretically be broken by sufficiently powerful quantum computers using Shor’s algorithm. PQC involves new mathematical constructs—like lattice-based or code-based cryptography—that resist quantum attacks. Governments and standards bodies (e.g., NIST) are evaluating these methods to guide the transition. Organizations must plan migration to PQC early, updating cryptographic inventories and assessing compatibility. The shift aims to protect sensitive data even if quantum computing becomes widely accessible. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Post-quantum_cryptography).*

Question 108

# Define: Preemptive Multitasking

Answer 108

An operating system feature allowing it to control task execution timing, enhancing responsiveness and efficiency. ## Footnote Preemptive multitasking is an operating system capability that allows the OS to control how long a program can run on the CPU before giving other programs a chance to execute. The OS forcibly interrupts the currently running program to allow others to run, improving system responsiveness and efficiency. It's critical for ensuring fair resource distribution and system stability. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Preemption_(computing)).*

Question 109

# Define: Pressure Sensors

Answer 109

Pressure sensors monitor force exerted per unit area, commonly used to detect changes in fluid or gas pressure or sense physical contact in security systems. ## Footnote In cybersecurity or safety use cases, pressure sensors might trigger alarms when detecting unauthorized entry in floors, doors, or vaults. They also appear in industrial control systems, ensuring pipes or containers remain within safe operating thresholds. Accurate calibration is crucial; oversensitivity can cause false alarms. Properly deployed, pressure sensors provide a reliable layer of environmental or perimeter defense. *For more information, view this lecture on [Physical security- Part 4](https://courses.thorteaches.com/courses/take/cissp/lessons/19632100-physical-security-part-4). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Pressure_sensor).*

Question 110

# Define: Pretty Good Privacy Cryptosystem | (PGP)

Answer 110

A program offering data encryption and decryption to secure email communications and files. ## Footnote A data encryption and decryption program used for securing the privacy of email communications, files, and data storage. PGP uses a combination of symmetric-key cryptography and public-key cryptography to offer confidentiality, authentication, and integrity checking of data. It's widely regarded for its capability to provide robust security for digital communication, making it a popular choice for protecting sensitive email content. *For more information, view this lecture on [IPSec and PGP](https://courses.thorteaches.com/courses/take/cissp/lessons/19149746-ipsec-and-pgp). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Pretty_Good_Privacy).*

Question 111

# Define: Prime Number

Answer 111

A natural number greater than 1 with no positive divisors other than 1 and itself, key in cryptographic algorithms. ## Footnote A natural number greater than 1 that has no positive divisors other than 1 and itself. In other words, it can only be divided evenly by 1 and the number itself. Prime numbers are fundamental to various fields of mathematics and are especially important in number theory. In the context of IT and cybersecurity, prime numbers are crucial for cryptographic algorithms, particularly those involving public-key cryptography such as RSA, where large prime numbers are used to generate secure encryption keys. *For more information, view this lecture on [Asymmetric encryption- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19149672-asymmetric-encryption-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Prime_number).*

Question 112

# Define: Private Cloud

Answer 112

A cloud infrastructure exclusively used by one organization, providing control over data and applications. ## Footnote A cloud computing model where the infrastructure and services are exclusively used by a single organization. It is used to provide scalable and flexible computing resources while maintaining control and security over the data and applications. Examples include private cloud solutions from providers such as Amazon Web Services (AWS) and Microsoft Azure. *For more information, view this lecture on [Virtualization, Cloud, and Distributed Computing - Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/18591376-virtualization-cloud-and-distributed-computing-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Cloud_computing#Private_cloud).*

Question 113

# Define: Private Cloud Threats

Answer 113

Security challenges unique to private cloud environments, such as unauthorized access and data leakage. ## Footnote Private cloud threats specifically refer to security challenges that arise within cloud computing environments that are exclusively operated for a single organization. These threats can compromise the confidentiality, integrity, and availability of data and resources. Examples of private cloud threats include unauthorized access, data leakage, inadequate identity and access management, and lack of compliance with industry standards.

Question 114

# Define: Process for Attack Simulation and Threat Analysis | (PASTA)

Answer 114

A risk-centric threat modeling methodology to identify and assess potential risks. ## Footnote The Process for Attack Simulation and Threat Analysis (PASTA) is a risk-centric threat modeling framework designed to identify and assess potential risks and threats to an information system. PASTA focuses on integrating business objectives and technical requirements, considering the attacker's perspective, and prioritizing risks for remediation. It is implemented through seven stages, from defining objectives to validating remediation measures. *For more information, view this lecture on [Secure design principles](https://courses.thorteaches.com/courses/take/cissp/lessons/25340659-secure-design-principles). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Threat_model#Process_for_Attack_Simulation_and_Threat_Analysis_(PASTA)).*

Question 115

# Define: Protection Domain

Answer 115

A defined area in a system with specific access permissions to control resource access. ## Footnote A security concept in which resources like files and memory are grouped within defined boundaries, each with specific access permissions. Protection domains ensure that processes and users can only access the resources for which they are authorized.

Question 116

# Define: Protection Profile

Answer 116

A document defining security requirements for a product class, used in Common Criteria evaluations. ## Footnote A Protection Profile is a document used in the Common Criteria certification process that defines a standard set of security requirements for a specific category of products or systems. It provides a benchmark against which products can be evaluated to ensure they meet a certain level of security performance. Examples include protection profiles for network firewalls, smart cards, and operating systems. *For more information, view this lecture on [Security evaluation models.](https://courses.thorteaches.com/courses/take/cissp/lessons/18591287-security-evaluation-models). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Protection_Profile).*

Question 117

# Define: Protection Ring

Answer 117

A layered security mechanism within operating systems that controls access to resources. ## Footnote A security mechanism that divides a system into different levels of security, with each level providing different levels of access to system resources. This is commonly used in operating systems to prevent unauthorized access to sensitive data and system resources. Examples include the rings in the Intel x86 architecture and the Kernel Mode in Windows. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Protection_ring).*

Question 118

# Define: PTZ | (Pan/Tilt/Zoom)

Answer 118

PTZ describes surveillance cameras with motorized capabilities to pan horizontally, tilt vertically, and zoom in or out, offering flexible, wide-range video monitoring. ## Footnote PTZ cameras allow operators or automated systems to track moving subjects, focus on suspicious areas, or switch viewing angles in real time. They often feature presets for sweeping patrols, covering large perimeters with fewer devices. Integrations with motion detection or analytics provide intelligent alerts. Effective PTZ use can deter intruders, support forensic investigations, and reduce blind spots in security setups. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/PTZ_camera).*

Question 119

# Define: Public Cloud

Answer 119

A cloud service model providing on-demand resources over the internet to the general public. ## Footnote A type of cloud computing service that is provided over the Internet and is available to the general public. This is commonly used by organizations and individuals to access and use computing resources on demand without the need to purchase and maintain their own hardware and software. Examples include Amazon Web Services and Microsoft Azure. *For more information, view this lecture on [Virtualization, Cloud, and Distributed Computing - Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/18591376-virtualization-cloud-and-distributed-computing-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Cloud_computing#Public_cloud).*

Question 120

# Define: Public Key

Answer 120

A cryptographic key that is publicly disclosed and used to encrypt data or verify digital signatures; part of an asymmetric key pair with a private key. ## Footnote A publicly disclosed key that is part of a cryptographic pair, which includes a private key. The public key is used to encrypt data or verify digital signatures, while the private key decrypts the data or creates the signature. *For more information, view this lecture on [Asymmetric encryption- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19149672-asymmetric-encryption-part-1). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Public-key_cryptography).*

Question 121

# Define: Public Key Certificate

Answer 121

A digital certificate that uses a public key to authenticate the identity of the holder, crucial in secure online transactions. ## Footnote A digital certificate that uses a public key to verify the identity of the certificate holder. These certificates are part of a public key infrastructure, integral to establishing secure communications over the internet. *For more information, view this lecture on [Digital signatures](https://courses.thorteaches.com/courses/take/cissp/lessons/19149728-digital-signatures). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Public_key_certificate).*

Question 122

# Define: Public Key Cryptography | (PKC)

Answer 122

A cryptographic system utilizing a pair of keys—a public key for encryption and a private key for decryption—to secure communications. ## Footnote A cryptographic system that uses a pair of keys, a public key and a private key, to encrypt and decrypt messages. It is used in secure communication and digital signatures. Examples include RSA, ECC, and Diffie-Hellman algorithms. *For more information, view this lecture on [Digital signatures](https://courses.thorteaches.com/courses/take/cissp/lessons/19149728-digital-signatures). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Public-key_cryptography).*

Question 123

# Define: Public Key Cryptosystem

Answer 123

A cryptographic system that uses a public key for encryption and a paired private key for decryption to secure data and communications. ## Footnote A cryptographic system that uses pairs of keys - one which may be disseminated publicly to encrypt data (public key) and another which is known only to the owner (private key) for decryption. In a public key cryptosystem, anyone can encrypt a message using the receiver's public key, but only the holder of the paired private key can decrypt it, thereby ensuring confidentiality. Additionally, these systems can be used for digital signatures, where a message is signed with a sender's private key and can be verified by anyone having access to the sender's public key, thus providing authentication and non-repudiation. Well-known examples of public key cryptosystems include RSA, DSA, and ECC (Elliptic Curve Cryptography). Public key cryptography is foundational to many aspects of digital security and is widely used in securing communications, data, and transactions over the Internet. *For more information, view this lecture on [Digital Signatures](https://courses.thorteaches.com/courses/take/cissp/lessons/19149728-digital-signatures). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Public-key_cryptography).*

Question 124

# Define: Public Key Infrastructure | (PKI)

Answer 124

A framework of roles, policies, hardware, software, and procedures needed to create, manage, distribute, use, store, and revoke digital certificates. ## Footnote A framework that enables secure electronic transactions through the use of a paired public and private cryptographic key. PKI ensures secure user authentication, digital signatures, and encrypted data transmission, providing a foundation for trust in digital communications. *For more information, view this lecture on [Digital Signatures](https://courses.thorteaches.com/courses/take/cissp/lessons/19149728-digital-signatures). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Public_key_infrastructure).*

Question 125

# Define: Quantum Channel/States

Answer 125

Transmission pathways in quantum systems enabling state transfer and communication. ## Footnote Quantum Channel/States refers to the mechanisms and properties involved in transmitting quantum information. Quantum channels facilitate the transfer of quantum states between parties, playing a critical role in quantum communication and computing, where maintaining coherence and entanglement is essential for secure and efficient information exchange. *For more information, view this lecture on [Quantum Cryptography and Key Distribution](https://courses.thorteaches.com/courses/take/cissp/lessons/54398651-new-2024-quantum-cryptography-and-key-distribution). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Quantum_channel).*

Question 126

# Define: Quantum Cryptography

Answer 126

The use of quantum mechanical properties to perform cryptographic tasks, offering theoretically unbreakable encryption. ## Footnote The use of quantum mechanics principles to secure communication. It is used in the field of information security to provide secure, unbreakable encryption for data transmission. Examples include the use of quantum keys to encrypt messages, the use of quantum states to detect eavesdropping, and the use of quantum computers to break classical encryption schemes. *For more information, view this lecture on [Quantum Cryptography and Key Distribution](https://courses.thorteaches.com/courses/take/cissp/lessons/54398651-new-2024-quantum-cryptography-and-key-distribution). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Quantum_cryptography).*

Question 127

# Define: Quantum Entanglement

Answer 127

A phenomenon where particles become interlinked, affecting each other's states instantly. ## Footnote Quantum Entanglement is a quantum physics phenomenon where particles become connected in such a way that the state of one instantly influences the state of another, regardless of the distance between them. This counterintuitive behavior has significant implications for quantum computing, cryptography, and our overall understanding of physical reality. *For more information, view this lecture on [Quantum Cryptography and Key Distribution](https://courses.thorteaches.com/courses/take/cissp/lessons/54398651-new-2024-quantum-cryptography-and-key-distribution). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Quantum_entanglement).*

Question 128

# Define: Quantum Key Distribution | (QKD)

Answer 128

QKD leverages quantum mechanics to securely exchange cryptographic keys, making any interception attempts detectable by the communicating parties. ## Footnote Using properties like photon polarization, QKD sends key bits in a way that disturbance caused by eavesdropping becomes evident. Once verified as tamper-free, these bits form a one-time pad or feed into classical encryption algorithms. While QKD promises provable security, challenges include limited distance, specialized hardware, and integration with existing networks. Research continues to expand QKD’s range and feasibility. It’s seen as a vital technology for safeguarding sensitive government or financial communications against future quantum threats. *For more information, view this lecture on [Quantum Cryptography and Key Distribution](https://courses.thorteaches.com/courses/take/cissp/lessons/54398651-new-2024-quantum-cryptography-and-key-distribution). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Quantum_key_distribution).*

Question 129

# Define: Radio Frequency Identification | (RFID)

Answer 129

A technology using electromagnetic fields to automatically identify and track tags attached to objects, aiding in inventory and security. ## Footnote A technology that uses electromagnetic fields to automatically identify and track objects, such as RFID tags attached to products or animals. It is used in supply chain management, inventory tracking, and security systems to automate data collection and tracking. Examples include using RFID tags to track packages in a warehouse, using RFID scanners to check inventory levels in a store, and using RFID-enabled access control systems to secure buildings or restricted areas. *For more information, view this lecture on [Physical Security- Part 4](https://courses.thorteaches.com/courses/take/cissp/lessons/19632100-physical-security-part-4). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Radio-frequency_identification).*

Question 130

# Define: Radio Frequency Interference | (RFI)

Answer 130

Unwanted electromagnetic noise that disrupts electronic devices, leading to poor performance or malfunctions. ## Footnote The unwanted effects of electromagnetic signals on electronic devices or systems. It is a common issue in the field of telecommunications and can lead to degraded performance or even failure. Examples include the use of shielding and filtering to prevent RFI, the use of frequency coordination to avoid interference, and the use of isolation techniques to minimize the effects of RFI. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Electromagnetic_interference).*

Question 131

# Define: Rainbow Table

Answer 131

A precomputed table for reversing cryptographic hashes, used in password cracking to find hash collisions. ## Footnote A pre-computed table of hashes used to crack password hashes. It is a common tool in the field of information security and is used to accelerate the process of cracking passwords. Examples include the use of rainbow tables to crack simple passwords, the use of rainbow tables to crack complex passwords, and the use of rainbow tables to crack hashed passwords. *For more information, view this lecture on [Attacks on Our Cryptography- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/19423030-attacks-on-our-cryptography-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Rainbow_table).*

Question 132

# Define: Random Number Generators | (RNGs)

Answer 132

Devices or algorithms generating sequences of numbers lacking any predictable patterns, used in cryptography and simulations. ## Footnote Algorithms or devices that produce random or unpredictable sequences of numbers or data. They are used in cryptography and security systems to generate strong encryption keys, randomize data for statistical analysis, and prevent bias or predictability in simulations or tests. Examples include using hardware RNGs based on physical processes, such as thermal noise or radioactive decay, and using software RNGs based on mathematical functions, such as the Mersenne Twister or the SHA-1 hash algorithm. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Random_number_generation).*

Question 133

# Define: Randomization

Answer 133

Introducing unpredictability in a system, such as in cryptographic key generation, to enhance security against attacks. ## Footnote The process of introducing randomness into a system in order to improve security and make it more difficult for attackers to predict and exploit vulnerabilities. It is used in cryptography and security protocols to make it harder for attackers to predict and crack passwords or keys. Examples include random password generation, randomized encryption keys, and random number generation. *For more information, view this lecture on [Introduction to Cryptography- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19121869-introduction-to-cryptography-part-1) and [Introduction to Cryptography- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/19121903-introduction-to-cryptography-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Randomness).*

Question 134

# Define: Randomizer | (in IT)

Answer 134

A tool or function generating random data, often used in software testing and cryptography. ## Footnote A utility or function that generates random or pseudorandom data. Used in software testing and gaming to ensure unpredictability and fairness, such as randomizing test cases or game scenarios. In cybersecurity, it may involve randomizing session tokens or security challenges to prevent attacks. *For more information, view this lecture on [Introduction to Cryptography- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19121869-introduction-to-cryptography-part-1) and [Introduction to Cryptography- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/19121903-introduction-to-cryptography-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Randomness).*

Question 135

# Define: Randomness

Answer 135

The lack of pattern or predictability in events or data, valued in cryptography and statistical sampling. ## Footnote The property of being unpredictable and lacking a definite pattern or order. It is used in security to create unpredictable values and prevent attackers from guessing or predicting sensitive information. Examples of randomness include the use of a random number generator to create a password or the shuffling of a deck of cards. *For more information, view this lecture on [Introduction to Cryptography- Part 1](https://courses.thorteaches.com/courses/take/cissp/lessons/19121869-introduction-to-cryptography-part-1) and [Introduction to Cryptography- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/19121903-introduction-to-cryptography-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Randomness).*

Question 136

# Define: RC6 | (Rivest Cipher 6)

Answer 136

A symmetric key block cipher designed for efficiency and security in software. ## Footnote RC6 is a symmetric key block cipher derived from RC5, known for its efficiency and robust security properties in software environments. It employs operations like multiplication, rotation, and XOR across multiple rounds, allowing flexibility in block and key sizes, and was once a strong candidate for the Advanced Encryption Standard. *For more information, view this lecture on [Symmetric Encryption- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/19215140-symmetric-encryption-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/RC6).*

Question 137

# Define: Redundancy Check

Answer 137

A method of verifying the integrity of data by adding extra information that can be used to detect errors during transmission or storage. ## Footnote A process used to ensure data integrity during storage or transmission by including additional data (such as parity bits or checksums). This added data allows the detection and sometimes correction of errors that may have occurred, enhancing the reliability of the data being delivered or retrieved. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Cyclic_redundancy_check).*

Question 138

# Define: Reference Monitor

Answer 138

An abstract machine that mediates all access to objects by subjects, ensuring that security policies are enforced. ## Footnote A critical component of an access control system. It's responsible for regulating interactions between subjects (users or processes) and objects (resources) within a system. This is done by enforcing an access control policy that determines who or what can access certain resources and what operations they can perform. Its design must be tamper-proof and constantly active to ensure reliable enforcement of security policies. *For more information, view this lecture on [Secure Operating Systems and Software Architecture](https://courses.thorteaches.com/courses/take/cissp/lessons/18591315-secure-operating-systems-and-software-architecture). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Reference_monitor).*

Question 139

# Define: Register

Answer 139

A small, fast storage location within a computer's CPU that holds data temporarily during processing and execution. ## Footnote A register is a small, high-speed storage area within a computer's processor designed to hold and quickly access data needed for computation. Each processor core contains multiple registers, which temporarily store specific types of data, like instruction operands, addresses, and control information. They play a crucial role in the overall system performance, acting as a bridge between memory and the processing unit for rapid data access. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Processor_register).*

Question 140

# Define: Registration Authority | (RA)

Answer 140

An entity that verifies user identities before issuing digital certificates, part of Public Key Infrastructure (PKI). ## Footnote A trusted entity that is responsible for verifying the identity of individuals or organizations and issuing digital certificates. It is used in public key infrastructure (PKI) to establish trust and secure communication. Examples include a CA that verifies the identity of a user before issuing a digital certificate or an RA that verifies the identity of an organization before issuing an SSL certificate. *For more information, view this lecture on [Digital Signatures](https://courses.thorteaches.com/courses/take/cissp/lessons/19149728-digital-signatures). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Public_key_infrastructure).*

Question 141

# Define: Remote Terminal Units | (RTUs)

Answer 141

Field devices in industrial control systems that collect data from sensors and send it to a master system. ## Footnote Devices deployed in the field that interface with sensors or other equipment to collect real-time data, typically in industrial control systems like SCADA. They serve as a focal point for monitoring and controlling physical processes, converting sensor signals into digital data that can be sent to a central system or controller for processing and action. Given their critical role, these units often include features for local decision-making and control, even under network outage conditions. *For more information, view this lecture on [Industrial Control Systems](https://courses.thorteaches.com/courses/take/cissp/lessons/19121862-industrial-control-systems). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Remote_terminal_unit).*

Question 142

# Define: Resource Encapsulation | (in IT)

Answer 142

Isolating resources with strict access interfaces, enhancing security and system integrity. ## Footnote The practice of isolating resources and controlling access to them through strict interfaces or APIs. This helps ensure that only authorized processes or users can interact with sensitive data or system components, enhancing security and stability.

Question 143

# Define: Return-Oriented Programming Attacks | (ROP)

Answer 143

Sophisticated cyber-attacks that exploit existing code sequences in a system's memory to bypass security protections. ## Footnote A sophisticated attack that manipulates how a program uses its control flow by executing existing code sequences, known as gadgets, found in a system's memory. This technique avoids direct code injection, making it a stealthy way to execute arbitrary operations, and is commonly used to circumvent non-executable memory protections. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Return-oriented_programming).*

Question 144

# Define: RFC 2104

Answer 144

A publication describing HMAC, a construction for creating a message authentication code from a cryptographic hash function and a secret key. ## Footnote A Request for Comments (RFC) that specifies the HMAC (Hash-based Message Authentication Code) construction for creating a message authentication code derived from a cryptographic hash function and a secret key. HMAC is widely used for data integrity and authentication, ensuring that messages are not altered or tampered with in transit. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/HMAC).*

Question 145

# Define: RFC 3161

Answer 145

An RFC that defines a protocol for securely and verifiably time-stamping data to establish its existence at a specific point in time. ## Footnote This RFC defines a protocol for Internet X.509 Public Key Infrastructure Time-Stamp Protocol (TSP). It provides a means for proving that a set of data existed at a certain point in time and is used in digital signatures, software distribution, and other fields where time-stamping is critical for establishing data integrity and non-repudiation. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Trusted_timestamping).*

Question 146

# Define: RFC 6960

Answer 146

An RFC that specifies the Online Certificate Status Protocol for obtaining the revocation status of an X.509 digital certificate. ## Footnote An RFC that specifies the Online Certificate Status Protocol (OCSP), which is used for obtaining the revocation status of an X.509 digital certificate. OCSP serves as an alternative to certificate revocation lists (CRLs), providing more real-time, on-demand information about whether a certificate is still valid. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Online_Certificate_Status_Protocol).*

Question 147

# Define: RFC 8907

Answer 147

A specification document for the Telnet protocol, which is used for remote terminal connection services. ## Footnote The Request for Comments (RFC) document 8907 is a technical specification that defines the Telnet protocol, which is a standard Internet protocol used for remote terminal connection services. RFC 8907 consolidates previous documentation and updates the specifications for the Telnet protocol to reflect common implementation practices. It is intended as a reference for the development of Telnet clients and servers, offering guidance on how to implement the protocol in a way that maintains compatibility and interoperability with existing Telnet applications. Despite its importance in the history of networking, the lack of encryption in Telnet has led to its decline in favor of more secure protocols such as SSH (Secure Shell) for remote access and management of network devices and systems.

Question 148

# Define: Rijndael

Answer 148

The block cipher algorithm selected as the Advanced Encryption Standard (AES) for its security and flexibility. ## Footnote The block cipher algorithm that was chosen by the U.S. National Institute of Standards and Technology (NIST) to be the Advanced Encryption Standard (AES). Rijndael was selected due to its robust security, computational efficiency, flexibility, and ease of implementation across a wide range of platforms. It supports a variety of block and key sizes and is widely used worldwide for encryption in various applications and protocols to ensure the confidentiality of data. *For more information, view this lecture on [Symmetric encryption- Part 2.](https://courses.thorteaches.com/courses/take/cissp/lessons/19215140-symmetric-encryption-part-2) Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Advanced_Encryption_Standard).*

Question 149

# Define: RIPEMD-160 | (Race Integrity Primitives Evaluation Message Digest)

Answer 149

A cryptographic hash function used for its unique signature generation capability, providing data integrity. ## Footnote A cryptographic hash function used to generate a unique fixed-size signature for a message or data file. It is used in cybersecurity to verify the integrity of data and detect tampering. Examples include generating a message digest for a software update or a financial transaction. *For more information, view this lecture on [Hashing- Part 2.](https://courses.thorteaches.com/courses/take/cissp/lessons/19314170-hashing-part-2) Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/RIPEMD).*

Question 150

# Define: Risks by Cloud Service Model

Answer 150

Security issues related to different cloud service models such as IaaS, PaaS, and SaaS. ## Footnote This entails the potential security issues linked to different cloud service models, namely infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). Each model has varying degrees of control over data and resources, leading to a unique set of potential security risks.

Question 151

# Define: Rivest Cipher 4 | (RC4)

Answer 151

A stream cipher formerly used in WEP and SSL/TLS, now deprecated due to security vulnerabilities. ## Footnote A stream cipher that was widely used in various protocols, most notably in WEP for wireless network security and in early versions of SSL/TLS for securing web traffic. However, due to vulnerabilities that have been discovered over time, RC4 is no longer considered secure and has been largely replaced by more robust encryption methods. *For more information, view this lecture on [Symmetric encryption- Part 2.](https://courses.thorteaches.com/courses/take/cissp/lessons/19215140-symmetric-encryption-part-2) Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/RC4).*

Question 152

# Define: Rivest Cipher 5 | (RC5)

Answer 152

A flexible block cipher notable for variable block sizes, key sizes, and rounds; less used in practice today. ## Footnote A block cipher known for its simplicity and flexibility in terms of block size, key size, and the number of encryption rounds. While RC5 has influenced cryptographic research, it is not commonly used in modern applications, with more secure and standardized algorithms like AES being favored in current cryptographic practices. *For more information, view this lecture on [Symmetric encryption- Part 2.](https://courses.thorteaches.com/courses/take/cissp/lessons/19215140-symmetric-encryption-part-2) Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/RC5).*

Question 153

# Define: Rogue Administrators in Virtualization

Answer 153

Individuals within a virtualized environment who misuse their high-level access for malicious purposes. ## Footnote The individuals who, within a virtualized environment, have the ability to exploit their high-level access privileges for malicious intent. A rogue administrator may execute harmful actions such as data theft, unauthorized system modification, or disruption of services, all of which could lead to significant security breaches. Measures such as strict access controls, monitoring, and logging are used to mitigate the potential threat posed by rogue administrators.

Question 154

# Define: Root of Trust

Answer 154

A trusted set of functions providing the foundation for the security of a computing platform. ## Footnote A set of functions in the trusted computing base with properties that let them be trusted. The Root of Trust serves as a foundation for other system components, ensuring that the hardware, firmware, and software loaded on the system are authentic, unaltered, and, therefore, trustworthy. It is a critical concept in security design to establish a chain of trust, where each component of a system can be validated and trusted based on this root. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Trusted_platform_module).*

Question 155

# Define: Rootkit

Answer 155

Malicious software that gains unauthorized access to a computer system and hides its existence. ## Footnote A type of malicious software designed to gain privileged access to a computer or network, often by masking its existence or operating in stealth mode to evade detection. Rootkits can intercept and change system operations, creating a backdoor for continued access, altering log files, and more. They're notoriously difficult to detect and remove, presenting a significant threat to system integrity. *For more information, view this lecture on [Malware- Part 2](https://courses.thorteaches.com/courses/take/cissp/lessons/18684286-malware-part-2). Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Rootkit).*

Question 156

# Define: Rounds | (in Block Ciphers)

Answer 156

Encryption processes that transform plaintext into ciphertext, increasing complexity and security. ## Footnote The process or sequence of encryption operations that transforms plaintext into ciphertext and vice versa. Multiple rounds increase the complexity of the encryption and make it more difficult for an unauthorized entity to reverse-engineer the original message. The number of rounds varies depending on the specific encryption algorithm in use. *For more information, view this lecture on [Symmetric encryption- Part 2.](https://courses.thorteaches.com/courses/take/cissp/lessons/19215140-symmetric-encryption-part-2) Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Block_cipher).*

Question 157

# Define: RS-232 Interface

Answer 157

A long-established serial communication standard for connecting devices like computers and modems. ## Footnote A serial communication standard used to connect devices, such as computers and terminals. It is used to transmit data between devices, typically at slow speeds. Examples include a serial cable used to connect a computer to a modem or a serial port used to connect a terminal to a mainframe. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/RS-232).*

Question 158

# Define: RSA | (Rivest-Shamir-Adleman)

Answer 158

A public key cryptosystem that uses asymmetric encryption to secure data transmission. ## Footnote A widely accepted public key cryptosystem developed by Ron Rivest, Adi Shamir, and Leonard Adleman. It enables secure data transmission and is commonly used for securing sensitive data, particularly when sent over an insecure network. RSA's security comes from the computational difficulty of factoring large composite integers, which is the product of two large prime numbers. RSA is employed in a multitude of security-focused applications, including SSL for web traffic, secure email, and digital signatures. *For more information, view this lecture on [Asymmetric encryption- Part 1.](https://courses.thorteaches.com/courses/take/cissp/lessons/19149672-asymmetric-encryption-part-1) Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/RSA_(cryptosystem)).*

Question 159

# Define: Running Key Cipher

Answer 159

A cipher using a long text as the key to encrypt messages, ensuring security through key uniqueness. ## Footnote A type of cipher that uses a long, pre-determined piece of text (known as the "key") to encrypt and decrypt messages. It is used in cryptography to encode and decode secret messages. Examples of running key cipher include using a book as the key to encrypt a message or using a string of random numbers as the key to decrypt a message. *For more information, view this lecture on [The history of Cryptography - Part 1.](https://courses.thorteaches.com/courses/take/cissp/lessons/19149612-the-history-of-cryptography-part-1) Or visit this [Wikipedia page](https://en.wikipedia.org/wiki/Running_key_cipher).*

Question 160

# Define: Runtime

Answer 160

The period when a program is active and executing in a system, essential for performance and error handling. ## Footnote The period when a program or process is running or executing within a system after being loaded into memory. During this period, the program is operational and can interact with system resources (like memory and CPU) and with users. Monitoring and managing runtime is essential for performance optimization, error handling, and ensuring the smooth operation of system processes. *For more information, visit this [Wikipedia page](https://en.wikipedia.org/wiki/Run_time_(program_lifecycle_phase)).*