〇：Graham-Denning Model

The Graham-Denning model addresses how access rights between subjects and objects are defined, developed, and integrated. It defines a basic set of rights in terms of the commands that a particular subject can execute on an object. The model has eight basic protective rights or rules on how to safely perform these types of functions

×：Brewer-Nash Model

It is incorrect because its purpose is to provide access control that can be changed dynamically according to the user’s previous actions. The main purpose is to protect against conflicts of interest due to user access attempts. For example, if a large marketing firm provides marketing promotions and materials for two banks, the employee responsible for the Bank A project should not be able to see information about Bank B, the marketing firm’s other bank customer. A conflict of interest could arise because the banks are competitors. If the project manager of the marketing firm’s Project A can see information about Bank B’s new marketing campaign, he may attempt to execute it rather than promote it to please more direct customers. Marketing firms have a bad reputation when internal employees can act irresponsibly.

×：Clark-Wilson Model

The Clark-Wilson model is incorrect because it is implemented to protect data integrity and ensure that transactions are properly formatted within the application. Subjects can only access objects through authorized programs. Segregation of duties is enforced. Auditing is required. The Clark-Wilson model addresses three integrity goals: preventing changes by unauthorized users, preventing inappropriate changes by unauthorized users, and maintaining internal and external consistency.

×：Bell-LaPadula Model

This model was developed to address concerns about the security of U.S. military systems and the leakage of classified information, and is incorrect. The primary goal of the model is to prevent unauthorized access to classified information. It is a state machine model that enforces the confidentiality aspect of access control. Matrices and security levels are used to determine if a subject has access to different objects. Specific rules are applied to control how objects interact with each other compared to the subject’s object classification.

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：Data Encryption

The Advanced Encryption Standard (AES) is a data encryption standard developed to improve upon the previous de facto standard, Data Encryption Standard (DES). As a symmetric algorithm, AES is used to encrypt data. Therefore, the correct answer is “data encryption.

There are other situations where AES is used in the other choices, but encrypting data is the most focused or better answer. Thus, there are cases where all of the choices are correct.

×：Data integrity

This is a characteristic of digital signatures.

×：Key recovery

It is a property of decryption and key escrow.

×：Symmetric key distribution

Using symmetric keys for AES distribution lowers the key delivery problem.

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：Public key infrastructure is a mechanism configuration for public key cryptographic distribution, and public key cryptography is another name for asymmetric encryption.

Public key cryptography is asymmetric cryptography. The terms are used interchangeably. Public key cryptography is a concept within the Public Key Infrastructure (PKI), which consists of various parts such as Certificate Authorities, Registration Authorities, certificates, keys, programs, and users. Public Key Infrastructure is used to identify and create users, distribute and maintain certificates, revoke and distribute certificates, maintain encryption keys, and for the purpose of encrypted communication and authentication.

×：Public key infrastructure uses symmetric algorithms and public key cryptography uses asymmetric algorithms.

This is incorrect because the public key infrastructure uses a hybrid system of symmetric and asymmetric key algorithms and methods. Public key cryptography is to use asymmetric algorithms. Therefore, asymmetric and public key cryptography are interchangeable, meaning they are the same. Examples of asymmetric algorithms are RSA, elliptic curve cryptography (ECC), Diffie-Hellman, and El Gamal.

×：Public key infrastructure is used to perform key exchange, while public key cryptography is used to create public/private key pairs.

This is incorrect because public key cryptography is the use of asymmetric algorithms used to create public/private key pairs, perform key exchange, and generate and verify digital signatures.

×：Public key infrastructure provides confidentiality and integrity, while public key cryptography provides authentication and non-repudiation.

Incorrect because the public key infrastructure itself does not provide authentication, non-repudiation, confidentiality, or integrity.

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：Run an algorithm that identifies unused committed memory and informs the operating system that memory is available.

This answer describes the function of the garbage collector, not the memory manager. The garbage collector is a countermeasure against memory leaks. It is software that runs an algorithm to identify unused committed memory and tells the operating system to mark that memory as “available. Different types of garbage collectors work with different operating systems, programming languages, and algorithms.

In some cases, a four-choice question can be answered without knowing the exact answer; since there is only one correct answer in a four-choice question, the answers can be grouped together to reduce it to “since they are saying the same thing, it is not right that only one of them is correct, therefore they are both wrong.

There are two answers to the effect of controlling the process to handle memory appropriately, but if the memory manager does not have that functionality, both would be correct, and therefore can be eliminated from the choices in the first place.

×：If processes need to use the same shared memory segment, use complex controls to guarantee integrity and confidentiality.

If processes need to use the same shared memory segment, the memory manager uses complex controls to ensure integrity and confidentiality. This is important to protect memory and the data in it, since two or more processes can share access to the same segment with potentially different access rights. The memory manager also allows many users with different levels of access rights to interact with the same application running on a single memory segment.

×：Restrict processes to interact only with the memory segments allocated to them.

The memory manager is responsible for limiting the interaction of processes to only those memory segments allocated to them. This responsibility falls under the protection category and helps prevent processes from accessing segments to which they are not allowed. Another protection responsibility of the memory manager is to provide access control to memory segments.

×：Swap contents from RAM to hard drive as needed.

This is incorrect because swapping contents from RAM to hard drive as needed is the role of memory managers in the relocation category. When RAM and secondary storage are combined, they become virtual memory. The system uses the hard drive space to extend the RAM memory space. Another relocation responsibility is to provide pointers for applications when instructions and memory segments are moved to another location in main memory.

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：Execution Domain Switching

Execution domain switching occurs when the CPU needs to move between executing instructions for a more trusted process versus a less trusted process. Trusted Computing Base (TCB) allows processes to switch domains in a secure manner to access different levels of information based on sensitivity. Execution domain switching occurs when a process needs to invoke a process in a higher protection ring. The CPU executes the user-mode instruction back into privileged mode.

At first glance, this is a geeky problem that does not make sense. But don’t give up. Since there is no such thing as skipping, you can only get a right or wrong answer when the question is posed, so it is preferable to answer the question with some degree of prediction.

From this point on, let’s consider how to answer the questions. If you look at the question text and read it to the point where it reads, “You moved from one area to the other, and that was a security breach?” If you can read to that point, then you have two choices: deny or “stop the process,” or change or “switch the domain of execution. Next, the question text reads “if you need to access it,” which is asking how to accomplish this objective, not whether or not you should.

×：Execution of I/O operations

This is incorrect because input/output (I/O) operations are not initiated to ensure security when a process in one domain needs to access another domain in order to retrieve sensitive information. I/O operations are performed when input devices (such as a mouse or keyboard) and output devices (such as a monitor or printer, etc.) interact with an application or applications.

×：Stopping a Process

A process deactivation is one that occurs when a process instruction is fully executed by the CPU or when another process with a higher priority calls the CPU, which is incorrect. When a process is deactivated, new information about the new requesting process must be written to a register in the CPU. The TCB component must ensure that this is done, since the data replaced in the registers may be confidential.

×：Mapping from virtual memory to real memory

Incorrect because memory mapping occurs when a process needs its instructions and data processed by the CPU. The memory manager maps logical addresses to physical addresses so that the CPU knows where to place the data. This is the responsibility of the operating system’s memory manager.

〇：The most common method used is to change the most significant bit.

Steganography is a method of hiding data in other media types. One of the most common ways to embed messages in some types of media is using the least significant bit (LSB). This is because many types of files are modified and this is where sensitive data can be made visible and hidden without modifying the file. the LSB approach has been successful in hiding information within the graphics of high-resolution or sound-heavy audio files (high bit rate).

×：Hiding by abstraction.

Steganography is incorrect because it is concealment by abstraction. Security by obscurity means that someone uses secrecy as a way to protect an asset, rather than actually using the measure to secure something.

×：Just as encryption does, steganography is not a front for the existence of the sensitive data itself.

It is true that steganography does not draw attention to itself as does encryption. In other words, it is concealment by abstraction.

×：Media files are ideal for steganographic transmissions that are large in size.

This is incorrect because it is true that larger media files are ideal for steganographic transmissions because everyone needs to privately use multiple bits to manipulate with low likelihood of noticing.

〇：CA signs certificates.

A Certificate Authority (CA) is a trusted agency (or server) that maintains digital certificates. When a certificate is requested, the Registration Authority (RA) verifies the identity of the individual and passes the certificate request to the CA The CA creates the certificate, signs it, and maintains the certificate over its lifetime.

×：RA creates the certificate and CA signs it.

Incorrect because the RA does not create the certificate; the CA creates it and signs it; the RA performs authentication and registration tasks; establishes the RA, verifies the identity of the individual requesting the certificate, initiates the authentication process to the CA on behalf of the end user, and performs certificate life cycle RAs cannot issue certificates, but can act as a broker between the user and the CA When a user needs a new certificate, they make a request to the RA and the RA goes to the CA to verify all necessary identification before granting the request The RA verifies all necessary identification information before granting the request.

×：RA signs certificates.

The RA signs the certificate, which is incorrect because the RA does not sign the certificate; the CA signs the certificate; the RA verifies the user’s identifying information and then sends the certificate request to the CA.

×：The user signs the certificate.

Incorrect because the user has not signed the certificate; in a PKI environment, the user’s certificate is created and signed by the CA. The CA is a trusted third party that generates the user certificate holding its public key.

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：The cloud provider is provided a platform as a service that provides a computing platform that may include an operating system, database, and web servers.

Cloud computing is a term used to describe the aggregation of network and server technologies, each virtualized, to provide customers with a specific computing environment that matches their needs. This centralized control provides end users with self-service, broad access across multiple devices, resource pooling, rapid elasticity, and service monitoring capabilities.

There are different types of cloud computing products: IaaS provides virtualized servers in the cloud; PaaS allows applications to be developed individually; SaaS allows service providers to deploy services with no development required and with a choice of functionality; and IaaS allows customers to choose the type of service they want to use. ” The term “PaaS” must fit the definition of “PaaS” because it requires that “the original application configuration remains the same”. Thus, the correct answer is, “The cloud provider provides a computing platform that may include an operating system, database, and web server, where the platform as a service is provided.” The following is the correct answer

×：The cloud provider is provided with an infrastructure as a service that provides a computing platform that can include an operating system, database, and web servers.

IaaS Description.

×：The cloud provider is provided with software services that provide an infrastructure environment similar to that of a traditional data center.

This is a description of the operational benefits of cloud computing. It is not a definition.

×：The cloud provider provides software as a service in a computing platform environment where application functionality is internalized.

SaaS Description.

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.

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.

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：Common Criteria

Common Criteria was created in the early 1990s as a way to combine the strengths of both the Trustworthy Computer Systems Evaluation Criteria (TCSEC) and the Information Technology Security Evaluation Criteria (ITSEC) and eliminate their weaknesses. Common Criteria is more flexible than TCSEC and easier than ITSEC. Common Criteria is recognized worldwide and assists consumers by reducing the complexity of assessments and eliminating the need to understand the definitions and meanings of different assessments in different assessment schemes. This also helps manufacturers because they can now build a specific set of requirements when they want to market their products internationally, rather than having to meet several different evaluation criteria under different rules and requirements.

×：ITSEC

This is incorrect because it is not the most widely used information technology security evaluation standard. ITSEC was the first attempt to establish a single standard for evaluating the security attributes of computer systems and products in many European countries. In addition, ITSEC separates functionality and assurance in its evaluations, giving each a separate rating. It was developed to provide greater flexibility than TCSEC and addresses integrity, availability, and confidentiality in networked systems. The goal of ITSEC was to become the global standard for product evaluation, but it failed to achieve that goal and was replaced by Common Criteria.

×：Red Book

Wrong, as it is a U.S. government publication that addresses the topic of security evaluation of networks and network components. Formally titled Trusted Network Interpretation, it provides a framework for protecting different types of networks. Subjects accessing objects on the network must be controlled, monitored, and audited.

×：Orange Book

Incorrect as this is a U.S. Government publication that addresses government and military requirements and expectations for operating systems. The Orange Book is used to evaluate whether a product is suitable for the security characteristics and specific applications or functions required by the vendor. The Orange Book is used to review the functionality, effectiveness, and assurance of the product under evaluation, using classes designed to address typical patterns of security requirements. It provides a broad framework for building and evaluating trusted systems, with an emphasis on controlling which users have access to the system. We call it the Orange Book, but another name for it is Trusted Computer System Evaluation Criteria (TCSEC).

〇：Crime Prevention by Environmental Design (CPTED)

Crime Prevention by Environmental Design (CPTED) is a method by which crime can be reduced through proper design of the physical environment. It provides guidance on appropriate facility construction and environmental elements and crime prevention. It is used to guide the physical environment to behavioral effects that reduce crime.

×：Multi-layered defense model  

The multi-layered defense model is incorrect because it is a hierarchical architecture of physical, logical, and administrative security controls. The concept is that if one layer fails, the asset is protected by other layers. Layers should be moved from the perimeter toward the asset and implemented.

×：Hiding by Ambiguity

Concealment by ambiguity is a technique of concealment secured by concealment of information and is incorrect. Basically, it is better not to consider something to be a true secret if it is logically reachable, even if it is not public.

×：Access Control

Access control is incorrect because it is guidance by the placement of doors, fences, lighting, and landscaping as people enter. It is an abstract concept and would not fit into a concrete definition that combines sociology.

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.

〇：Encryption and decryption are more efficient.

Elliptic curves are rich mathematical structures that have shown usefulness in many different types of applications. Elliptic curve cryptography (ECC) differs from other asymmetric algorithms because of its efficiency; ECC is efficient because it is computationally less expensive than other asymmetric algorithms. In most cases, the longer the key, the more bloated the computation to secure it, but ECC can provide the same level of protection with a shorter key size than RSA requires.

×：Provides digital signatures, secure key distribution, and encryption.

ECC is wrong because it is not the only asymmetric algorithm that provides digital signatures, secure key distribution, and encryption provided by other asymmetric algorithms such as RSA.

×：Calculated in finite discrete logarithms.

Wrong because Diffie-Hellman and El-Gamal compute with finite discrete logarithms.

×：Uses a large percentage of resources to perform the encryption.

Incorrect because ECC when compared to other asymmetric algorithms uses much less resources. Some devices, such as wireless devices and cell phones, have limited processing power, storage, power, and bandwidth. Resource utilization efficiency is very important for the encryption methods used in this type.