3702 - cyber threats and defense Flashcards
Mid-term
What is a one-way hash function? Is SHA-3 a one-way hash function?
SHA-3is a one way hash functions because it makes it very difficult to derive the original message from the hash. This in turn allows SHA-3 to provide security against malicious attacks.
What is the limit on the message size in SHA-512?
The limit on the message size of SHA-512 is 2^128 -1 bits, its worth noting that this is theoretical and has not been tested.
What are the two basic functions used in encryption algorithms?
The two basic functions that are used in encryption algorithms are substitution and permutation, substitution is used to replace elements of plain text with other elements while permutation is used to change the arrangement of the elements.
List four ways in which secret keys can be distributed to two communicating parties.
Manual key distribution, in which the key can be exchanged physically.
Public key infrastructure, a transaction that can be secured via a third party.
Diffie-Hellman key exchange, exchanging the key over a secure channel.
Key distribution centers (KDC), which store the key for each pair of communicating parties.
. What are the two general approaches to attacking a cipher?
The two best general approaches to attacking a cipher are Cipher only attacks in which the attack is mainly focused on the ciphertext or known plain text where the main target are plaintexts.
What is a length extension attack?
A length of extensions attack is when malicious party use there knowledge of a earlier generated hash function and add new data to said hash function to compromise the original message.
If you are called in to assess the cybersecurity status of a business entity, discuss how you will make your assessment based only on the lecture on the “Overview” of cybersecurity
I would focus on the chain of cause and effect that dictates the relationship between threats, vulnerabilities, countermeasures, and attacks. First, I would try to determine the potential harm or threats that could befall the system. Then, I would look for vulnerabilities that could enable those threats. I would then analyze how an attack could be carried out to exploit that vulnerability. Finally, I would look for countermeasures to possibly stop the attack and bolster security defenses in case of such an attack.
What is the attack surface of a system? Give 3 ways to reduce the attack surface of a system
attack surface is the scope of how far a potential attack could spread within a given system. 1) Examine where you vulnerabilities are in terms of software, employee etc…. 2) understand what kind of error are those vulnerabilities prone to experiencing, human error and malicious behaviors are some examples.3) Implement firewalls to monitor and control incoming and outgoing network traffic, and create clear guidelines to maintain a secure environment. For example, enforce policies such as banning the use of external USB drives to mitigate potential risks.
The risk to an asset depends on its vulnerabilities and the threats it faces. As a cybersecurity specialist, which of the factors can you effectively control to reduce the risk?
you can control the likelihood of a threat, by implementing detection and alarm systems for potential vulnerabilities. you could also update systems and applications to decrease the likelihood of an attack. Finally you can train employees, on how to manage a safe a secure systems.
How many keys are required for four students to communicate using a symmetric cipher? Explain your answer.
The amount of keys required for four students to use a symmetric cipher would be six keys in total. Each combination of students would require one key, and the four of them can make six unique combinations.
Explain why hashing can or cannot be used to ensure the integrity of a message.
The nature of hashing makes it so that any changes to its content generate a new hash. While that does secure the integrity of the original message, that does not mean that the sender will receive the original. If someone were to pose as the sender and send a different message with a different hash, then effectively there will be no way to prove that it is the intended message from the intended messenger.
Watch the random number video. How are random numbers used in cryptography?
Random numbers are used in a number of ways in cryptography. Random numbers can be used for creating strong passwords and keys, as well as encrypted messages, and even making applications more secure.
Watch the threat modeling video and explain the importance of threat modeling.
The importance of threat modeling is that it helps determine who might attack you or your organization as well as how they might attack you. It’s worth knowing that threat modeling is also a great resource for finding creative bugs or vulnerabilities in your system. Modeling also tells you what you need to protect and also gives you a path to stopping potential attackers.
What are the four basic means of authentication of a user’s identity? Give at least one example of each
The four basic means of authenticating a user identity are, something you know like a password or a pin. The next one is something you have a physical characteristic maybe you are a phone. Next is something you are. This is something that is unique to you like your fingerprint for example or your DNA. Finally, somewhere you are using your location, for example or maybe when you get a specific office building, you can access certain features that you normally cannot.
why are passwords stored in hashed form?
Why are passwords stored in hashed form? I believe this is because of the inherent nature of hashing, where it is very volatile when it comes to change. This means that any sort of tampering with the original message generates a new hash, and the fact that it is very hard to decrypt.
How does salting the password hash help?
Salting protects passwords by making sure that the original values of the hash can’t be guessed based on known hash values and their meanings. It also stops identical hashes from being created.
In the case of biometric authentication, if a static biometric is used, then the biometric capture device is authenticated. However, device authentication is not required in the case of dynamic biometric. Explain why authentication is needed in stable biometric but not in dynamic biometric.
Why is authentication needed in stable biometrics but not in dynamic biometrics? Because stable biometrics don’t change over time, and when that data is captured once, it is effectively going to remain the same. Dynamic biometrics, like handwriting, for example, are subject to change, meaning that over the course of a person’s lifetime, they might not keep the same handwriting due to various factors.
