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：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 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：* (star) Integrity Property

The Biba model defines a model with completeness as having two axioms. The * (star) Integrity Property is that the subordinate’s document is to be seen and there is no Read Down. The * (star) Integrity Property is that there is no Write Up, that is, no rewriting of the supervisor’s document. If the Simple Integrity Axiom is not followed, the subordinate’s document will be seen and may absorb unclassified and incorrect information at a lower level. If the * (star) Integrity Property is not followed, a supervisor’s document will be rewritten, which will release incorrect information to the supervisor who sees it. Therefore, both are integrity conditions.

×：Simple Integrity Property

The Simple Integrity Property is a constraint on Read Down.

×：Strong Tranquillity Axiom

The Strong Tranquillity Axiom is the constraint not to change permissions while the system is running.

×：Weak Tranquillity Axiom

Weak Tranquillity Axiom means do not change privileges until the attribute is inconsistent.

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.

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：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：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：Keys are generated from a master key.

To generate a composite key, a master key is created and a symmetric key (subkey) is generated. The key derivation function generates the encryption key from the secret value. The secret value can be a master key, passphrase, or password. The key derivation function (KDF) generates a key for symmetric key ciphers from a given password.

×：Session keys are generated from each other.

Session keys are generated from each other, not from the master key, which is incorrect.

×：Asymmetric ciphers are used to encrypt symmetric keys.

It is incorrect because key encryption is not even related to the key derivation function (KDF).

×：The master key is generated from the session key.

Reverse, incorrect. Session keys are generally generated from master keys.

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.

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：Conflict condition

A race condition is present when a process performs a task on a shared resource and the sequence could be in the wrong order. 2 or more processes can have a race condition if they use a shared resource, like data in a variable. It is important that processes perform their functions in the correct sequence.

×：Backdoors

Backdoors are incorrect because they are “listening” services on certain ports. Backdoors are implemented by attackers to allow easy access to the system without authenticating as a normal system user.

×：Maintenance Hooks

Maintenance hooks are specific software codes that allow easy and unauthorized access to sensitive parts of a software product. Software programmers use maintenance hooks to allow them to get quick access to the code so that they can make fixes in immediate, but this is dangerous.

×：Data validation errors

Data validation errors are wrong because an attacker cannot operate on the process execution sequence.

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 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：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：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.

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.

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.

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.