Certified Ethical Hacker (CEH v12) — Question 56

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 meets the specifications of a symmetric key block cipher with a 128-bit block size and supports key sizes up to 256 bits. Options A, C, and D do not fit these criteria; HMAC is a hashing algorithm, IDEA has a 64-bit block size, and Blowfish, while a block cipher, has a maximum key size of 448 bits but a 64-bit block size.