Ethical Hacking Cryptography and Encryption 2 — Questions and Answers
Question 1: Which symmetric encryption algorithm is considered the current US government standard and is used widely in security applications?
- DES
- 3DES
- AES (Correct answer)
- Blowfish
Correct answer: AES
AES (Advanced Encryption Standard) was adopted by NIST in 2001 as the US federal standard, supporting 128, 192, and 256-bit key sizes and is considered highly secure.
Question 2: What is a 'hash collision' and why does it matter for security?
- Two different encryption keys producing similar outputs
- Two different inputs producing the same hash output, undermining hash integrity (Correct answer)
- A hash function failing to produce output for certain inputs
- Two identical inputs producing different hashes
Correct answer: Two different inputs producing the same hash output, undermining hash integrity
A hash collision occurs when two different input values produce identical hash outputs, compromising integrity verification and allowing attackers to substitute malicious files undetected.
Question 3: What does 'salting' a password hash mean?
- Encrypting the hash with a symmetric key
- Adding a unique random value to each password before hashing to prevent rainbow table attacks (Correct answer)
- Storing the hash in a separate database table
- Hashing the password multiple times to increase complexity
Correct answer: Adding a unique random value to each password before hashing to prevent rainbow table attacks
Salting adds a unique random value to each password before hashing, ensuring identical passwords produce different hashes and rendering rainbow table attacks ineffective.
Question 4: Which asymmetric algorithm is widely used for digital signatures and secure key exchange in SSL/TLS?
- AES
- DES
- RSA (Correct answer)
- SHA-256
Correct answer: RSA
RSA (Rivest-Shamir-Adleman) is a widely used asymmetric algorithm for digital signatures, encryption, and key exchange, with security based on the difficulty of factoring large prime numbers.
Question 5: What is 'perfect forward secrecy' (PFS) in cryptography?
- Ensuring all future data is encrypted with the same key
- Using unique session keys so past sessions remain secure even if long-term keys are compromised (Correct answer)
- Preventing any single key from decrypting all past and future traffic
- Generating encryption keys from hardware random number generators
Correct answer: Using unique session keys so past sessions remain secure even if long-term keys are compromised
Perfect Forward Secrecy ensures each session uses a unique ephemeral key, so compromising the long-term private key cannot decrypt previously recorded sessions.
Question 6: What type of attack exploits the statistical probability that two people in a group share a birthday to find hash collisions faster than brute force?
- Replay attack
- Birthday attack (Correct answer)
- Side-channel attack
- Chosen-plaintext attack
Correct answer: Birthday attack
The birthday attack exploits the birthday paradox to find two inputs with the same hash significantly faster than expected, reducing the security of hash functions.
Ethical Hacking Cryptography and Encryption 2
Which symmetric encryption algorithm is considered the current US government standard and is used widely in security applications?