CREST Cryptography & PKI

Question 1

Which cryptographic algorithm is considered asymmetric and commonly used for key exchange in TLS?

Accepted Answer

RSA

Answer

RSA is an asymmetric algorithm widely used for key exchange and digital signatures in TLS handshakes.

Question 2

What is the primary purpose of a Certificate Authority (CA) in PKI?

Accepted Answer

To issue and sign digital certificates

Answer

A Certificate Authority issues and digitally signs certificates, binding public keys to identities and establishing trust.

Question 3

Which of the following describes a collision attack against a hash function?

Accepted Answer

Finding two different inputs that produce the same hash output

Answer

A collision attack finds two distinct inputs that yield the same hash digest, undermining data integrity guarantees.

Question 4

What does perfect forward secrecy (PFS) ensure in TLS?

Accepted Answer

Past session keys remain secure even if the long-term private key is compromised

Answer

PFS uses ephemeral key exchange so that compromise of the server's long-term key cannot decrypt previously recorded sessions.

Question 5

Which mode of AES operation produces ciphertext blocks that are independent of each other, making it susceptible to block-swapping attacks?

Accepted Answer

ECB (Electronic Codebook)

Answer

ECB encrypts each block independently, so identical plaintext blocks produce identical ciphertext blocks, enabling block-swapping and pattern analysis.

(CREST) Council for Registered Ethical Security Testers Practice Test

(CREST) Council for Registered Ethical Security Testers Practice Test

CREST Cryptography & PKI