Certified Ethical Hacker (CEH v11) — Question 64

This form of encryption algorithm is a symmetric key block cipher that is characterized by a 128-bit block size, and its key size can be up to 256 bits. Which among the following is this encryption algorithm?

Answer options

• A. HMAC encryption algorithm
• B. Twofish encryption algorithm
• C. IDEA
• D. Blowfish encryption algorithm

Correct answer: B

Explanation

The correct answer is B, Twofish encryption algorithm, as it is specifically designed as a symmetric key block cipher with a 128-bit block size and a maximum key size of 256 bits. The other options do not meet these criteria, with HMAC being a hashing algorithm, IDEA having a different block size, and Blowfish using a smaller block size.