Question

Compare AES to DES. For each of the following elements of DES, indicate the comparable element in AES or explain why it is not needed in AES:a.Swapping of halves of the blockb. f functionc.permutation Pd. XOR of the f function output with the left half of the blocke. XOR of the subkey material with the input to the f function.

Answer 1

Answer:

See explaination for the comparison

Explanation:

Comparison Of AES & DES:

DES(Data Encryption Standard)

​In DES the data block is always been divided into two of the halves.

It works on the Feistel Cipher Structure.

The plaintext is of the 64 bits.

DES has 16 rounds in it.

The rounds that are in DES are as follows:

Expansion

Permutation

XOR

S-box

P-box

Swap

DES has a smaller key which is less secure as compared to AES

In speed, the DES is comparatively slower.

AES(Advanced Encryption Standard)

​In AES the entire data block is always processed as a single matrix.

It works on the principle of substitution and permutation.

The plaintext in AES varies from 128 bits ,192 bits, 256 bits, etc.

AES has a larger key size as compared to the DES.

There are many variations to the rounds in AES and is dependent on the bits of the encryption.They are as follows: 128-bits algorithm consists of 10 rounds. 192-bits algorithm consists of 12 rounds. 256-bits algorithm consists of 14 rounds.

The names for the rounds are as follows:

Subbytes

Shiftrows

Mix Columns

AddRoundkeys.

AES is having large secret key comapratively to the DES which is more secure.

Comparing the speed for the encryptions AES is faster than DES.

a.) AddRoundKey

b.) Since AES is not Feistel cipher this step is not essential.

c.) ByteSub is there.

d.) ShiftRow and MixColumn

e.) No swaping of halves