Certified Ethical Hacker Cryptography Fundamentals 3 — Questions and Answers
Question 1: Which hashing algorithm is considered broken and should not be used for security purposes?
- SHA-256
- MD5 (Correct answer)
- SHA-3
- bcrypt
Correct answer: MD5
MD5 is vulnerable to collision attacks and is no longer considered secure.
Question 2: What technique adds random data to a password before hashing to defend against rainbow tables?
- Salting (Correct answer)
- Padding
- Chaining
- Tunneling
Correct answer: Salting
Salting adds unique random data to each password so identical passwords hash differently.
Question 3: Which cipher mode requires an initialization vector (IV) to randomize the first block?
- ECB
- CBC (Correct answer)
- Plaintext mode
- Hash mode
Correct answer: CBC
CBC mode uses an IV to ensure identical plaintext blocks encrypt differently.
Question 4: Why is ECB mode generally discouraged for encrypting large amounts of data?
- It is too slow
- Identical plaintext blocks produce identical ciphertext (Correct answer)
- It requires asymmetric keys
- It cannot use AES
Correct answer: Identical plaintext blocks produce identical ciphertext
ECB encrypts each block independently, revealing patterns in the plaintext.
Question 5: What is the primary purpose of a Certificate Authority (CA) in a PKI?
- Generate symmetric keys
- Issue and verify digital certificates (Correct answer)
- Encrypt all network traffic
- Store passwords
Correct answer: Issue and verify digital certificates
A CA issues digital certificates that bind public keys to verified identities.
Question 6: Which attack attempts every possible key until the correct one is found?
- Brute-force attack (Correct answer)
- Replay attack
- Phishing attack
- SQL injection
Correct answer: Brute-force attack
A brute-force attack systematically tries all possible keys or passwords.
Question 7: What does the 'integrity' goal of cryptography ensure?
- Data is kept secret
- Data has not been altered (Correct answer)
- Data is always available
- Data is compressed
Correct answer: Data has not been altered
Integrity ensures that data has not been modified in transit or storage.
Certified Ethical Hacker Cryptography Fundamentals 3
Which hashing algorithm is considered broken and should not be used for security purposes?