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.

A collision is when the hash value of two different data from one hash function is the same. Hashing is one-way cryptography, which means that the original plaintext is no longer known to be one or the other.

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.

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：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：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.

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.

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.

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：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.

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：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：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：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：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：Multiple processes are using the same resources.

The system uses hard drive space (called swap space) that is reserved to expand RAM memory space. When the system fills up volatile memory space, data is written from memory to the hard drive. When a program requests access to this data, it is returned from the hard drive to memory in specific units called page frames. Accessing data stored on hard drive pages takes longer than accessing data stored in memory because it requires read/write access to the physical disk. A security issue with using virtual swap space is that two or more processes can use the same resources and corrupt or damage data.

×：Allowing cookies to remain persistent in memory

This is incorrect because virtual storage is not associated with cookies. Virtual storage uses hard drive space to extend RAM memory space. Cookies are small text files used primarily by web browsers. Cookies can contain credentials for web sites, site preferences, and shopping history. Cookies are also commonly used to maintain web server-based sessions.

×：Side-channel attacks are possible.

Side-channel attacks are incorrect because they are physical attacks. This type of attack gathers information about how a mechanism (e.g., smart card or encryption processor) works from abandoned radiation, time spent processing, power consumed to perform a task, etc. Using the information, reverse engineer the mechanism to reveal how it performs its security task. This is not related to virtual storage.

×：Two processes can perform a denial of service attack.

The biggest threat within a system where resources are shared between processes is that one process can adversely affect the resources of another process, since the operating system requires memory to be shared among all resources. This is especially true in the case of memory. It is possible for two processes to work together to perform a denial of service attack, but this is only one of the attacks that can be performed with or without the use of virtual storage.

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.

〇：The sender encrypts the message digest with his/her private key.

A digital signature is a hash value encrypted with the sender’s private key. The act of digitally signing means encrypting the hash value of the message with his/her private key. The sender would encrypt that hash value using her private key. When the recipient receives the message, she performs a hash function on the message and generates the hash value herself. She then decrypts the hash value (digital signature) sent with the sender’s public key. The receiver compares the two values and, if they are the same, can verify that the message was not altered during transmission.

×：The sender encrypts the message digest with his/her public key.

The sender is wrong because if the message encrypts the digest with his/her public key, the recipient cannot decrypt it. The recipient needs access to the sender’s private key, which must not occur. The private key must always be kept secret.

×：The receiver encrypts the message digest with his/her private key.

The receiver is wrong because the message must decrypt the digest with the sender’s public key. The message digest is encrypted with the sender’s private key, which can only be decrypted with the sender’s public key.

×：The receiver encrypts the message digest with his/her public key.

The receiver is wrong because the message must decrypt the digest with the sender’s public key. The message digest is encrypted with the sender’s private key, which can only be decrypted with the sender’s public key.

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).