Advanced Cryptography Interview Questions

Cryptography plays a critical role in securing assets in digital space. This blog listed out Interview Questions and Answers that may be asked in an interview process of a job for a cyber security role.

Q. What is Blowfish in the field of cryptography?

Ans: Blowfish is a symmetric key block cipher of 64-bit size and key length varies from 32 bits to 448 bits. This algorithm is developed in 1993 by Bruce Schneier and is able to replace the DES algorithm. As of now, blowfish is secure against any known vulnerabilities.

Q. What is Skipjack in the field of cryptography?

Ans: Skipjack is an encryption algorithm that uses an 80-bit key to encrypt or decrypt 64-bit block data.

Q. What is Twofish in the field of cryptography?

Ans: Blowfish is a symmetric key block cipher of 128-bit size and key length varies up to 256 bits. Twofish is an improved version of the Blowfish algorithm.

Q. What is the Diffie-Hellman Algorithm?

Ans: Diffie-Hellman algorithm used to secure communication on a public channel. This algorithm is based on Elliptic Curve Cryptography (ECC) and uses the concept of elliptic curves over finite fields.

Q. What are Public and Private keys in the field of Cryptography?

Ans: Public key and Private key both are used as a key pair generated by an asymmetric algorithm.

Q. What is the importance of the Key Length of Encryption Algorithm?

Ans: Key length is a critical aspect to determine the strength of the encryption algorithm.

Q. What is the maximum Key Length of RSA, DSA, and Elliptic Curve Cryptography?

Ans:

Algorithm	Maximum Key Length
RSA	4096 bits
DSA	2048 bits
Elliptical Curve Cryptography	256 bits

Q. Explain the concept of Hash Functions.

Ans: A hash function is a function used to convert arbitrary data to fixed-size values (also called hash values or digest). These functions are used to check the integrity of data.

Q. What is Public Key Infrastructure (PKI)?

Ans: A Public Key Infrastructure (PKI) is a system for the generation, distribution, and revoke of Digital Signature Certificates (DSC).

Q. List out some Cryptographic Attacks.

Ans: Below is some cryptographic attacks:

• Birthday attack
• Hash function security summary
• Rainbow table
• Side Channel attacks

Q. What are the common applications of cryptography to secure networking?

Ans:

• Secure communication
• Authentication of identity
• Password storage
• Reliability of transmission

Q. What is WPA encryption?

Ans: Wi-Fi Protected Access (WPA) is a security standard introduced in 2003 to secure wireless network systems. WPA replaced Wired Equivalent Privacy (WEP) as this protocol offers more security in user authorization and managing security keys. WPA uses Temporal Key Integrity Protocol (TKIP) to secure wireless traffic. WPA is now obsolete as WPA2 provides stronger encryption.

Additional Questions

1. How are digital signatures generated and verified?
2. What is Safer in the field of cryptography?
3. What is a One-time Pad?
4. What is a Birthday Attack?
5. What is the Secure Hash Algorithm?
6. What are Message Authentication Codes (macs)?
7. How do digital timestamps support Digital Signatures?
8. Is private key encryption to verify identity a weakness?
9. Can Hash Length Extension attacks be avoided by changing the data structure?
10. Is it possible to send encrypted data over an unencrypted network while hiding the fact that it is encrypted?
11. How password-based encryption works?
12. Is SHA-256 + Salt still safe for password storage?
13. What are the privacy advantages of a DNS encryption service such as DNScrypt?
14. Why can't hashes be reversed?
15. How can you encrypt email messages?
16. Can I slow down a brute force attack by encoding password input data?
17. How does a Digital Signature Certificate (DSC) work?
18. What are the different classes of Digital Signature Certificates?
19. What is an electronic document?