〇：The security kernel implements and executes the reference monitor

The Trusted Computing Base (TCB) is a complete combination of protection mechanisms for a system. These are in the form of hardware, software, and firmware. These same components also comprise the security kernel. Reference monitors are access control concepts implemented and enforced by the security kernel via hardware, software, and firmware. In doing so, it ensures that the security kernel, the subject, has the proper permissions to access the object it is requesting. The subject, be it a program, user, or process, cannot access the requesting file, program, or resource until it is proven that it has the proper access rights.

×：The reference monitor is the core of the Trusted Computing Base (TCP), which is comprised of the security kernel.

This is incorrect because the reference monitor is not the core of the TCB. The core of the TCB is the security kernel, and the security kernel implements the concepts of the reference monitor. The reference monitor is a concept about access control. It is often referred to as an “abstract machine” because it is not a physical component.

×：The reference monitor implements and executes the security kernel.

The reference monitor does not implement and execute the security kernel, which is incorrect. On the contrary, the security kernel implements and executes the reference monitor. The reference monitor is an abstract concept, while the security kernel is a combination of hardware, software, and firmware in a trusted computing base.

×：The security kernel, i.e., the abstract machine, implements the concept of a reference monitor.

This is incorrect because abstract machine is not another name for security kernel. Abstract machine is another name for the reference monitor. This concept ensures that the abstract machine acts as an intermediary between the subject and the object, ensuring that the subject has the necessary rights to access the object it is requesting and protecting the subject from unauthorized access and modification. The security kernel functions to perform these activities.

The Kerckhoffs’s principle is the idea that cryptography should be secure even if everything but the private key is known. When encrypting data, one decides on a private key and how to encrypt it using that private key. Kerckhoffs says that even if it is known how it is encrypted, it should not be deciphered as long as the secret key is not discovered. Encryption has been with the history of human warfare. The main purpose is to communicate a strategy to one’s allies without being discovered by the enemy. In battle, its designs and encryption devices may be stolen by spies. Therefore, the encryption must be such that it cannot be solved without the key, no matter how much is known about how it works.

〇：Statistically predictable

The two main types of symmetric algorithms are block ciphers and stream ciphers. Block ciphers perform a mathematical function on a block of bits at a time. Stream ciphers do not divide the message into blocks. Instead, a stream cipher treats the message as a stream of bits and performs the mathematical function on each bit individually. If it were statistically predictable, it would not be a practical encryption technique in the first place.

×：Statistically Fair Keystreams

Statistically fair keystreams are an element of good stream ciphers. Therefore, it is incorrect. Another way to say a statistically unbiased keystream is that it is a highly random keystream that is difficult to predict.

×：The repetitive pattern of bit strings treated in a keystream is long.

Another way to say the randomness of a keystream is that it is highly random, with long repetitions = rarely repeated = highly random.

×：The keystream is irrelevant to the key.

A keystream that is not related to a key is an element of a good stream cipher. Therefore, it is incorrect. This is important because the key provides the randomness of the encryption process.

〇：TOGAF

The Open Group Architecture Framework (TOGAF) is a vendor-independent platform for the development and implementation of enterprise architecture. It focuses on the effective management of enterprise data using metamodels and service-oriented architectures (SOA). Proficient implementations of TOGAF aim to reduce fragmentation caused by inconsistencies between traditional IT systems and actual business processes. It also coordinates new changes and functionality so that new changes can be easily integrated into the enterprise platform.

×：Department of Defense Architecture Framework (DoDAF)

In accordance with the guidelines for the organization of the enterprise architecture of the U.S. Department of Defense systems, this is incorrect. It is also suitable for large, complex integrated systems in the military, civilian, and public sectors.

×：Capability Maturity Model Integration (CMMI) during software development.

It is inappropriate because it is a framework for the purpose of designing and further improving software. CMMI provides a standard for software development processes that can measure the maturity of the development process.

×：ISO/IEC 42010

Incorrect because it consists of recommended practices to simplify the design and conception of software-intensive system architectures. This standard provides a kind of language (terminology) to describe the different components of software architecture and how to integrate it into the development life cycle.

〇：The expiration date should be set short.

Key management is critical for proper protection. Part of key management is to determine the key’s period of validity, which would be determined by the sensitivity of the data being protected. For sensitive data, periodic key changes are required and the key’s expiration date will be shortened. On the other hand, for less secure data, a key with a longer expiration date is not a problem.

×：Keys should be deposited in case of backup or emergency.

This is incorrect because it is true that keys must be deposited in the event of a backup or emergency situation. Keys are at risk of being lost, destroyed or damaged. Backup copies must be available and readily accessible when needed.

×：Keys must not be made public.

Of course. It is a key.

×：Keys should be stored and transmitted by secure means.

Wrong, since it is true that keys should be stored and transmitted by secure means. Keys are stored before and after distribution. If keys are distributed to users, they must be stored in a secure location in the file system and used in a controlled manner.

〇：Operating system patching is easier.

This is an incorrect choice question. Virtualization does not simplify operating system patching. In fact, it complicates it by adding at least one additional operating system. Each operating system differs from the typical version configuration, adding to the complexity of patching. The server’s own operating system runs as a guest within the host environment. In addition to patching and maintaining the traditional server operating system, the virtualization software itself must be patched and maintained.

For this question, we do not require an understanding of all the technical systems of virtualization. What is required here is a selection of answers based on a process of elimination.

×：I can build a secure computing platform.

Building a secure computing platform may not be a feature of virtualization per se. However, can we build a secure environment? This is not a false choice because it cannot be ruled out.

×：It can provide fault and error containment.

Virtualization can be host independent. In terms of containment, it can be interpreted as being able to provide fault and error containment through independence from physical servers. Therefore, it cannot be denied and is therefore not an incorrect choice.

×：It can provide powerful debugging capabilities.

Virtualization can reproduce a unique environment, not just put up a clean virtual host. Therefore, it is undeniable and therefore out of the wrong choice.

〇：Well-Formed Transaction

In the Clark-Wilson model, subjects cannot access objects without going through some type of application or program that controls how this access is done. The subject (usually the user) can access the required object based on access rules within the application software, defined as “Well-Formed Transaction,” in conjunction with the application.

×：Childwall model

This is incorrect because it is another name for the Brewer Nash model created to provide access control that can be dynamically modified according to the user’s previous behavior. It is shaped by access attempts and conflicts of interest and does not allow information to flow between subjects and objects. In this model, a subject can only write to an object if the subject cannot read another object in a different data set.

×：Access tuples

The Clark-Wilson model is incorrect because it uses access triples instead of access tuples. The access triple is the subject program object. This ensures that the subject can only access the object through the authorized program.

×：Write Up and Write Down

The Clark-Wilson model is incorrect because there is no Write Up and Write Down. These rules relate to the Bell-LaPadula and Biba models. The Bell-LaPadula model contains a simple security rule that has not been read and a star property rule that has not been written down. The Biba model contains an unread simple completeness axiom and an unwritten star completeness axiom.

A key escrow system is one in which a third-party organization holds a copy of the public/private key pair. If the private key is stolen, all ciphers can be decrypted. Conversely, if it is lost, all ciphers cannot be decrypted. Therefore, you want to have a copy. However, if you have it yourself, it may be stolen if a break-in occurs, so you leave it with a third-party organization.

〇：Keys will need to be distributed via a secure transmission channel.

For two users to exchange messages encrypted with a symmetric algorithm, they need to figure out how to distribute the key first. If the key is compromised, all messages encrypted with that key can be decrypted and read by an intruder. Simply sending the key in an email message is not secure because the key is not protected and can easily be intercepted and used by an attacker.

×：Computation is more intensive than in asymmetric systems.

That is incorrect because it describes the advantages of symmetric algorithms. Symmetric algorithms tend to be very fast because they are less computationally intensive than asymmetric algorithms. They can encrypt and decrypt relatively quickly large amounts of data that take an unacceptable amount of time to encrypt and decrypt with asymmetric algorithms.

×：Much faster operation than asymmetric systems

Symmetric algorithms are faster than asymmetric systems, but this is an advantage. Therefore, it is incorrect.

×：Mathematically intensive tasks must be performed

Asymmetric algorithms are wrong because they perform a mathematically intensive task. Symmetric algorithms, on the other hand, perform relatively simple mathematical functions on bits during the encryption and decryption process.

In an asymmetric algorithm, every user must have at least one key pair (private and public key). In a public key system, each entity has a separate key. The formula for determining the number of keys needed in this environment is by the number N × 2, where N is the number of people to distribute. In other words, 260 x 2 = 520. Therefore, the correct answer is 520.

〇：One-time pad

Stream ciphers refer to one-time pad technology. In practice, stream ciphers cannot provide the level of protection that one-time pads do, but are practical.

×：AES

AES is incorrect because it is a symmetric block cipher. When a block cipher is used for encryption and decryption purposes, the message is divided into blocks of bits.

×：Block ciphers

Block ciphers are used for encryption and decryption purposes. The message is wrong because it is divided into blocks of bits.

×：RSA

RSA is incorrect because it is an asymmetric algorithm.

Compromise is when what used to be secure encryption becomes insecure due to the evolution of computers. Cryptography is based on the sharing of a single answer, a key, among those communicating. The key is generated by computer calculations, and a third party must solve a difficult problem that would take several years to derive. However, as the computational power of computers has evolved, it is now possible to solve difficult problems that could not be solved before. In this case, encryption is meaningless. This is the compromise caused by evolution. Therefore, the correct answer is “Compromise.

〇：Primary entry doors should have controlled access via swipe card or cryptographic locks. Secondary doors should not be secured from the inside and allowed entry. 

Data centers, server rooms, and wiring closets should be located in the core areas of the facility, near wiring distribution centers. Strict access control mechanisms and procedures should be implemented for these areas. Access control mechanisms can lock smart card readers, biometric readers, or a combination of these. These restricted areas should have only one access door, but fire code requirements typically dictate that there must be at least two doors in most data centers and server rooms. Only one door should be used for daily entry and exit and the other door should be used only in case of an emergency, i.e., if a fire breaks out in a data center or server room, the door should be locked. This second door should not be an access door, meaning people should not be able to come through this door. It should be locked, but should have a panic bar that will release the lock if it is used as an exit, pushed from the inside.

×：The primary and secondary entry doors must have control access via swipe cards or cryptographic locks.  

This is incorrect because even two entry doors should not be allowed to pass through with the identification, authentication, and authorization process. There should only be one entry point into the server room. No other door should provide an entry point, but can be used for an emergency exit. Therefore, secondary doors should be protected from the inside to prevent intrusion.

×：The primary entry door should have controlled access via a guard. Two doors should not be secured from the inside and allowed entry.

The main entry door to the server room is incorrect as it requires an identification, authentication, and authorization process to be performed. Swipe cards and cryptographic locks perform these functions. Server rooms should ideally not be directly accessible from public areas such as stairways, hallways, loading docks, elevators, and restrooms. This helps prevent foot traffic from casual passersby. Those who are by the door to the area to be secured should have a legitimate reason for being there, as opposed to those on the way to the meeting room, for example.

×：The main entry door must have controlled access via swipe card or crypto lock. Two doors must have security guards.  

Two doors should not have security guards, because it is wrong. The door should be protected from the inside simply so it cannot be used as an entry. Two-door must function as an emergency exit.

〇：TOC/TOU

Certain attacks can take advantage of the way a system processes requests and performs tasks. A TOC/TOU attack handles a series of steps that the system uses to complete a task. This type of attack takes advantage of the reliance on the timing of events occurring in a multitasking operating system; TOC/TOU is a software vulnerability that allows the use of condition checking (i.e., credential verification) and the results from that condition checking function. In the scenario in this question, the fact that the web application is likely correctly configured indicates that the programming code of this application has this type of vulnerability embedded in the code itself.

×：Buffer overflow

When too much data is accepted as input to a particular process, a buffer overflow occurs. This is incorrect because it does not match the event in the problem statement. A buffer is an allocated segment of memory. A buffer can overflow arbitrarily with too much data, but to be used by an attacker, the code inserted into the buffer must be of a specific length and require a command to be executed by the attacker. These types of attacks are usually exceptional in that the fault is segmented, or sensitive data is provided to the attacker.

×：Blind SQL Injection

Blind SQL injection attacks are wrong because they are a type of SQL injection attack that sends true or false questions to the database. In a basic SQL injection, the attacker sends specific instructions in SQL format to query the associated database. In a blind SQL attack, the attacker is limited to sending a series of true-false questions to the database in order to analyze the database responses and gather sensitive information.

×：Cross Site Request Forgery (CSRF)

Cross Site Request Forgery (CSRF) is incorrect because it is an attack type that attempts to trick the victim into loading a web page containing malicious requests or operations. The attack operation is performed within the context of the victim’s access rights. The request inherits the victim’s identity and performs undesirable functions for the victim. In this type of attack, the attacker can cause the victim’s system to perform unintended actions such as changing account information, retrieving account data, or logging out. This type of attack could be related to the scenario described in this question, but focuses on how the user can bypass the locking mechanism built into the web application. The logic in the programming code is incorrectly developed and the locking function is bypassed because a rigorous series of checks and usage sequences are not performed correctly.

〇：Conduct a risk analysis.

The first step in the procedure described, which is the first step to be taken only to deploy an effective physical security program, is to conduct a risk analysis to identify vulnerabilities and threats and to calculate the business impact of each threat. The team presents the results of the risk analysis to management to define an acceptable risk level for the physical security program. From there, the team evaluates and determines if the baseline is met by implementation. Once the team identifies its responses and implements the measures, performance is continually evaluated. These performances will be compared to the established baselines. If the baseline is maintained on an ongoing basis, the security program is successful because it does not exceed the company’s acceptable risk level.

×：Create a performance metric for the countermeasure.  

The procedure to create a countermeasure performance metric is incorrect because it is not the first step in creating a physical security program. If monitored on a performance basis, it can be used to determine how beneficial and effective the program is. It allows management to make business decisions when investing in physical security protection for the organization. The goal is to improve the performance of the physical security program, leading to a cost-effective way to reduce the company’s risk. You should establish a performance baseline and then continually evaluate performance to ensure that the firm’s protection goals are being met. Examples of possible performance metrics include: number of successful attacks, number of successful attacks, and time taken for attacks.

×：Design program.  

Designing the program is wrong because it should be done after the risk analysis. Once the level of risk is understood, then the design phase can be done to protect against the threats identified in the risk analysis. The design of deterrents, delays, detections, assessments, and responses will incorporate the necessary controls for each category of the program.

×：Implement countermeasures.  

Wrong because implementing countermeasures is one of the last steps in the process of deploying a physical security program.

〇：Increased Processing Power

The increased processing power of personal computers and servers has increased the probability of successful brute force and cracking attacks against security mechanisms that were not feasible a few years ago. Today’s processors can execute an incredible number of instructions per second. These instructions can be used to break passwords, encryption keys, or direct malicious packets to be sent to the victim’s system.

×：Increased circuitry, cache memory, and multiprogramming

This is incorrect because an increase does not make a particular type of attack more powerful. Multiprogramming means loading multiple programs or processes into memory at the same time. It allows antivirus software, word processors, firewalls, and e-mail clients to run simultaneously. Cache memory is a type of memory used for fast write and read operations. If the system expects that the program logic will need to access certain information many times during processing, the information is stored in cache memory for easy and quick access.

×：Dual-mode computation

The answer is not specific and does not measure conformance to the problem. When examining microprocessor advances, there is no actual dual-mode calculation.

×：Direct Memory Access I/O

Incorrect because this method transfers instructions and data between I/O (input/output) devices and the system’s memory without using the CPU. Direct Memory Access I/O significantly increases data transfer speed.

〇：Known Plaintext Attacks

A known-plaintext attack is a situation in which a decryptor can obtain plaintext indiscriminately. A ciphertext-alone attack is a situation where a decryptor can acquire ciphertext indiscriminately. A known-plaintext attack acquires the plaintext but does not know what ciphertext it is paired with, meaning that decryption is attempted with only two random ciphertexts. In this situation, it is difficult to decrypt. Therefore, the correct answer is “known-plaintext attack.

×：Selective Plaintext Attack

A choice-plaintext attack is a situation in which the decryptor can freely choose the plaintext to acquire and obtain the ciphertext.

×：Adaptive Choice Plaintext Attack

An adaptive choice-plaintext attack is a situation in which the decryptor can freely choose which plaintext to acquire and acquire the ciphertext, and can repeat the acquisition again after seeing the result.

×：None of the above

It is rare for the answer to be “none of the above” when the choice is “most of the above.

〇：A virtual firewall in bridge mode allows the firewall to monitor individual traffic links, while a firewall integrated into the hypervisor can monitor all activity taking place within the host system.

Virtual firewalls can be bridge-mode products that monitor individual communication links between virtual machines. They can also be integrated within a hypervisor in a virtual environment. The hypervisor is the software component that manages the virtual machines and monitors the execution of guest system software. When a firewall is embedded within the hypervisor, it can monitor all activities that occur within the host system.

×：A virtual firewall in bridge mode allows the firewall to monitor individual network links, while a firewall integrated into the hypervisor can monitor all activities taking place within the guest system.

A virtual firewall in bridge mode is incorrect because the firewall can monitor individual traffic links between hosts and not network links. Hypervisor integration allows the firewall to monitor all activities taking place within the guest system rather than the host system.

×：A virtual firewall in bridge mode allows the firewall to monitor individual traffic links, while a firewall integrated into the hypervisor can monitor all activities taking place within the guest system.

A virtual firewall in bridge mode is wrong because the firewall can monitor individual traffic links, and the hypervisor integration allows the firewall to monitor all activity taking place within the host system, but not the guest system. The hypervisor is the software component that manages the virtual machines and monitors the execution of the guest system software. A firewall, when embedded within the hypervisor, can monitor all activities taking place within the system.

×：A virtual firewall in bridge mode allows the firewall to monitor individual guest systems, while a firewall integrated into the hypervisor can monitor all activities taking place within the network system.

A virtual firewall in bridge mode allows the firewall to monitor individual traffic between guest systems, and a hypervisor integrated allows the firewall to monitor all activity taking place within the host system, not the network system, so Wrong.

〇：Zero Knowledge Proof

Zero Knowledge Proof means that someone can tell you something without telling you more information than you need to know. In cryptography, it means proving that you have a certain key without sharing that key or showing it to anyone. Zero knowledge proof (usually mathematical) is an interactive way for one party to prove to another that something is true without revealing anything sensitive.

×：Key Clustering

Key clustering is the phenomenon of encrypting the same plaintext with different keys, but with the same ciphertext.

×：Avoiding Birthday Attacks

An attacker can attempt to force a collision, called a birthday attack. This attack is based on the mathematical birthday paradox present in standard statistics. This is a cryptographic attack that uses probability theory to exploit the mathematics behind the birthday problem.

×：Provides data confidentiality

Provided via encryption when data is encrypted with a key, which is incorrect.

Cryptographic algorithms refer to the calculations to be encrypted, and even if the cryptographic algorithms were publicly available, it would take an enormous amount of effort to decipher them. cryptographic algorithms that provide modern cryptography, such as AES, are publicly available. On the other hand, in-house development is not recommended because, although it has the security of concealment, it requires a great deal of resources to be allocated.