Cryptography and Data Protection

1. What is "key exchange" in cryptography?

• A. Physically exchanging encryption keys
• B. A protocol for two parties to establish a shared secret key over an insecure channel ✓
• C. A type of digital signature
• D. A certificate renewal process

💡 Key exchange protocols (like Diffie-Hellman) allow two parties to establish a shared encryption key securely over a public channel.

2. What is "steganography"?

• A. A type of encryption
• B. Hiding secret information within ordinary, non-secret files or messages ✓
• C. A password technique
• D. A network protocol

💡 Steganography hides secret messages within innocent-looking files (images, audio) without the message being detectable.

3. What is "asymmetric encryption"?

• A. Using one key for everything
• B. Using a pair of mathematically related public and private keys ✓
• C. A type of hashing
• D. Encryption without keys

💡 Asymmetric encryption uses a public key to encrypt and a private key to decrypt. RSA and ECC are common examples.

4. What is "salting" in password storage?

• A. Adding flavor to passwords
• B. Adding random data to a password before hashing to prevent rainbow table attacks ✓
• C. A type of encryption
• D. Storing passwords in plain text

💡 Salting adds a unique random value to each password before hashing, ensuring identical passwords produce different hashes.

5. What is "SHA-256"?

• A. A type of symmetric encryption
• B. A widely used cryptographic hash function producing a 256-bit digest ✓
• C. A network protocol
• D. A digital certificate standard

💡 SHA-256 (Secure Hash Algorithm 256-bit) produces a unique 256-bit hash, widely used for data integrity verification and password hashing.

6. What does "AES" stand for?

• A. Advanced Encryption System
• B. Applied Encryption Standard
• C. Advanced Encryption Standard — the most widely used symmetric encryption algorithm ✓
• D. Automated Encryption System

💡 AES (Advanced Encryption Standard) is the most widely adopted symmetric encryption standard, used in HTTPS, Wi-Fi, and VPNs.

7. What is "hashing" in cybersecurity?

• A. Reversible encryption
• B. Converting data into a fixed-length string that cannot be reversed ✓
• C. A type of symmetric encryption
• D. Encoding data in base64

💡 Hashing converts data into a fixed-length digest using algorithms like SHA-256. It is one-way — you cannot reverse it to get the original.

8. What is "end-to-end encryption"?

• A. Encrypting only the start of transmission
• B. Encryption where only the communicating users can read the messages — not even the service provider ✓
• C. A type of server-side encryption
• D. Encrypting backups only

💡 End-to-end encryption ensures messages are encrypted on the sender's device and only decrypted on the recipient's device — WhatsApp and Signal use this.

9. What is a "digital signature"?

• A. A handwritten signature scanned
• B. A cryptographic technique verifying the authenticity and integrity of a message or document ✓
• C. A type of encryption
• D. A login method

💡 A digital signature uses asymmetric cryptography to verify that a message came from a specific sender and was not altered.

10. What is "symmetric encryption"?

• A. Using two different keys
• B. Using the same key for both encryption and decryption ✓
• C. A type of hashing
• D. Encryption without any key

💡 Symmetric encryption uses a single shared key for both encryption and decryption — examples include AES and DES.

11. What is "data masking"?

• A. Deleting sensitive data
• B. Replacing sensitive data with realistic but fictional data for testing or privacy ✓
• C. Encrypting all data
• D. Backing up data

💡 Data masking substitutes sensitive data with realistic fake data, protecting privacy while maintaining usability for testing or analytics.

12. What is "PKI" (Public Key Infrastructure)?

• A. A type of symmetric encryption
• B. A framework managing digital certificates and public-key encryption for trusted communications ✓
• C. A password management system
• D. A type of firewall

💡 PKI is a system of digital certificates, certificate authorities, and cryptographic protocols enabling secure, trusted communications.

13. What does "TLS" stand for?

• A. Transfer Layer Security
• B. Trusted Link System
• C. Transport Layer Security — the protocol securing internet communications ✓
• D. Transmission Layer Standard

💡 TLS (Transport Layer Security) is the cryptographic protocol securing HTTPS connections, replacing the older SSL protocol.

14. What is a "rainbow table attack"?

• A. A colorful hacking technique
• B. Using precomputed hash values to quickly crack password hashes ✓
• C. A type of brute force attack
• D. A network attack

💡 Rainbow tables are precomputed tables of hash values for common passwords, allowing attackers to quickly look up hashes to find passwords.

15. What is a "certificate authority" (CA)?

• A. A hacking group
• B. A trusted organization that issues digital certificates verifying website identity ✓
• C. A type of firewall
• D. A password manager

💡 A CA is a trusted entity that issues SSL/TLS certificates, verifying that a website is who it claims to be.