Question

__________ is a symmetric block cipher that was designed in 1993 by Bruce Schneier. This cryptography algorithm is intended as a replacement for DES. Like DES, it is a 16-round Feistel cipher working on 64-bit blocks. However, unlike DES, it can have varying key sizes ranging from 32 bits to 448 bits. There are really two parts to this algorithm. The first part handles the expansion of the key. The second part actually encrypts the data. The key expansion is handled in several steps. The first step is to break the original key into a set of subkeys. Specifically, a key of no more than 448 bits is separated into 4,168 bytes. There is a P-array and four 32-bit S-boxes. The P-array contains 18 32-bit subkeys, while each S-box contains 256 entries. A) AES (Advanced Encryption Standard)

B) DES (Data Encryption Standard)

C) Blowfish

D) RSA (Rivest–Shamir–Adleman)

Answer 1

Blowfish is the symmetric block cipher designed by Bruce Schneier in 1993 with variable key sizes, a P-array, and four S-boxes as part of its key expansion process.

Step-by-step explanation:

The symmetric block cipher designed in 1993 by Bruce Schneier as a potential replacement for DES is Blowfish. Like DES, Blowfish is a 16-round Feistel cipher that operates on 64-bit blocks. However, Blowfish is distinctive due to its variable key size, which can range from 32 bits to 448 bits. In the process of key expansion, the algorithm begins by dividing the original key into subkeys. A key's maximum length of 448 bits is broken down into 4,168 bytes, feeding a P-array with 18 32-bit subkeys and four S-boxes each containing 256 entries. Following the completion of key expansion, the second part of the algorithm proceeds to encrypt the data.