B. Twofish encryption algorithm Explanation: The Twofish encryption algorithm is a symmetric key block cipher that was designed to be secure, efficient, and flexible. It uses a block size of 128 bits and can have key sizes up to 256 bits, making it highly secure. Twofish was one of the five finalists in the Advanced Encryption Standard (AES) competition organized by the U.S. National Institute of Standards and Technology (NIST) in 1997. Although it was not selected as the winner, Twofish is still considered a highly secure encryption algorithm and is widely used in various applications.

A. HMAC encryption algorithm: Incorrect. HMAC stands for Hash-based Message Authentication Code. It is not an encryption algorithm but a type of message authentication code (MAC) involving a cryptographic hash function and a secret cryptographic key. B. Twofish encryption algorithm: Correct. Twofish is indeed a symmetric key block cipher with a block size of 128 bits, and it can use key sizes up to 256 bits. It was one of the five finalists for the Advanced Encryption Standard (AES) competition but was not selected as the AES. C. IDEA: Incorrect. IDEA, which stands for International Data Encryption Algorithm, is also a symmetric key block cipher but it uses a 64-bit block size and a 128-bit key size, which does not match the characteristics mentioned in your question. D. Blowfish encryption algorithm: Incorrect. Blowfish is a symmetric key block cipher that has a 64-bit block size and supports variable key lengths from 32 to 448 bits. It does not match the 128-bit block size described in the question.

B. Twofish encryption algorithm

The Twofish encryption algorithm is a symmetric key block cipher that was designed to be secure, efficient, and flexible. It uses a block size of 128 bits and can have key sizes up to 256 bits, making it highly secure.

Twofish uses a block size of 128 bits and key sizes up to 256 bits. It is a Feistel cipher CEH V12 Page 3330