CREST CREST Cryptography & Data Protection 3

Question 1

What does Perfect Forward Secrecy (PFS) guarantee in a TLS session?

Accepted Answer

Compromise of the long-term private key does not expose past session keys

Answer

PFS ensures that ephemeral session keys are generated independently, so compromising the server's long-term key cannot decrypt previously recorded sessions.

Question 2

Which standard defines requirements for key management and cryptographic modules in the US?

Accepted Answer

FIPS 140-2

Answer

FIPS 140-2 (and its successor FIPS 140-3) defines security requirements for cryptographic modules used in US federal systems.

Question 3

What is the purpose of salting a password before hashing it?

Accepted Answer

To prevent rainbow table and dictionary attacks

Answer

A unique random salt added before hashing ensures identical passwords produce different hashes, defeating precomputed rainbow tables.

Question 4

In a CREST assessment, discovering that an application uses ECB mode for AES encryption is significant because:

Accepted Answer

Identical plaintext blocks produce identical ciphertext blocks, leaking patterns

Answer

ECB mode encrypts each block independently, causing identical plaintext blocks to produce identical ciphertext, which can leak structural information.

Question 5

What type of cryptographic attack requires finding two different inputs that produce the same hash output?

Accepted Answer

Collision attack

Answer

A collision attack finds two distinct messages with identical hash values, undermining hash-based integrity mechanisms.

(CREST) Council for Registered Ethical Security Testers Practice Test

(CREST) Council for Registered Ethical Security Testers Practice Test

CREST CREST Cryptography & Data Protection 3