Which is better DES or AES?

DES is an acronym for Data Encryption Standard which is a symmetric key encryption to encrypt digital data. In addition, it is a type of block cipher with block size 64 bit. AES is Advance Encryption Standard which is also a block cipher with block size of 128 bits.

DES algorithm has 56 bit effective key size and has total 16 number of rounds. Let’s know about this algorithm works.

How DES works?

Steps to encrypt 64 bit block of data using DES algorithm.

Firstly, input 64 bit plain text and perform initial permutation.
Secondly, input 64 bit key and apply left circular shift to 56 bits key. After this, perform permuted choice round.
Generate 48 bit key as K1.
Apply K1 to Round 1 of DES.

Steps in each round as follows:

Firstly, divide the plain text into two equal halves of 32 bit each i.e say L0 and R0.
Secondly, rightmost 32 bits (R0) are expanded to generate 48 bits.
Thirdly, this 48 bits are XOR’ed with 48 bit key K1 generated in the above step 3.
Substitute the resultant 48 bits to 32 bits using S-Box.
Repeat the above steps for total 16 rounds.
After final round, swap the rightmost and leftmost 32 bits.
Lastly, perform inverse initial permutation and generate cipher text of 64 bits.

How AES Works?

AES has total 10, 12 or 14 rounds depending on the key size which can be 128, 192 or 256 bits.

Firstly, expand 16 byte key to get actual key block.
Secondly, initialize 16 byte plain text block known as state.
Perform XOR Operation between state and key block.

Similarly, Steps in each round:

Apply S-Box for substitution of plain text.
Rotate the rows of state.
Mix columns
Add round key which is XOR between state and key block.

First N-1 Rounds consists of following functions.

SubBytes
ShiftRows
MixColumns
AddRoundKey

Difference between DES and AES

DES	AES
Effective Key length is 56 bits.	Key length is 128, 192 or 256 bits.
Total number of rounds in des are 16.	Total rounds are 10,12 or 14 depends om key size.
Structure of DES is based on a feistal network.	Structure is based on substitution-permutation network.
DES is comparatively slower.	AES is much faster
Rounds include S-Box, P-Box, Swap	Rounds include SubBytes, MixColumns, AddRoundKey
DES is less secure because of smaller key size	AES is more secure than des.

Which is better?

AES is more secure and better as compared to DES because of its effective and variable key size. Secondly, It allows us to choose either 128, 192 or 256 bit key which makes it exponentially stronger than 56 bit key. Moreover, it makes it harder to break the encryption.

Summary

In conclusion, we have learnt in brief about des and aes algorithms. In addition, we have seen how each of the algorithm works and difference between both of them.

Hence, now we know which algorithm works better and is more secure.