Mock Exam: IT Security 2024

What is Kerckhoffs’s principle?

• Implementations of cryptographic algorithms must be protected against malicious modification.

• Access should be forbidden by default and only explicitly allowed when sufficient permissions are granted.

• The security of a larger system is only as good as the weakest link’s protection.

• A cryptographic algorithm should be considered insecure until it is mathematically proven to be secure.

• The security of a cryptographic system must only be based on the key and not on the secrecy of the algorithm.

In the security context, what is the definition of integrity?

• Recorded actions cannot be denied by the subjects who have carried them out.

• Data is not modified unnoticed without authorisation.

• Messages are hashed and signed before being sent to communication partners.

• Subjects are honest when communicating with others.

• A trusted third party (TTP) cannot read communication exchanged on the network.

In the security context, what is the definition of authenticity?

• The identity of an object or subject can be proven.

• Within a set of subjects, sent messages can be traced back to a sender.

• Subjects have to log in before being granted access to a system.

• User inputs are validated for their correctness before being operated on.

• Messages are sent unencrypted, as clear text.

Which of the following is not a cryptanalytic attack?

• Chiphertext-only attack

• Chosen signature attack

• Known plaintext attack

• Chosen ciphertext attack

• Chosen plaintext attack

What is the public key property (PKP)?

• It is impossible to decrypt data with the secret key.

• It is impossible to determine the secret key with only the knowledge about the public key.

• It is possible to decrypt the ciphertext only with the public key.

• It is impossible to encrypt data with the public key that can be decrypted with the secret key.

• It is possible to generate a signature with the public key.

Which measure helps to protect data integrity?

• Data economy

• Pseudonymisation

• Encryption

• Message Authentication Code

• Obfuscation

Alice and Bob communicate. For which of the following is Bob’s public key used?

• Carol signs a message to Bob.

• Alice encrypts a message to Bob.

• Bob signs a message to Alice.

• Bob encrypts a message to Alice.

• Alice signs a message to Bob.

Alice and Bob communicate. For which of the following is Bob’s private key used?

• Alice verifies the signature of a message from Bob.

• Carol decrypts a message from Alice.

• Alice decrypts a message from Bob.

• Bob verifies the signature of a message from Alice.

• Bob decrypts a message from Alice.

Alice and Bob communicate. For which of the following is Alice’s private key used?

• Carol signs a message to Bob.

• Bob signs a message to Alice.

• Bob encrypts a message to Alice.

• Alice encrypts a message to Bob.

• Alice signs a message to Bob.

In which situation is it essential to use the revocation certificate for a PGP key?

• You accidentally delete the only copy of your private key.

• You erroneously sign someone’s key, which you did not want to sign.

• You lose a flash drive with a copy of the private key.

• Your key has expired and you want to renew it.

• Your key has expired and you do not want to renew it.