Encryption Process
Each encryption process is divided into four subtasks. The first round process is as shown below:
Byte Substitution
The input bytes are shuffled using a fixed table(sbox). The result obtained is a matrix with four rows and four columns.
Row Shifting
Each of the four rows obtained in the substitution process is made to shift one step to the left.
The shifting needs to be implemented on the basis of the following criteria:
 The first row is kept static.
 The second row is moved one step to the left.
 The third row is moved two steps to the left.
 The fourth row is moved three steps to the left.
 The result obtained is the new matrix with the same bytes but only change in the position with respect to the other.
Column Shuffling
A special mathematical function shuffles all the four bytes of each and every column. The new four bytes of the column as the output are replacing the original input values of the column. Hence, the resultant is another matrix consisting of new 16 bytes.
Round Key Addition
The new matrix with 16 bytes is to be implemented over an XOR operator of 128 bytes. The result obtained is the ciphertext.
If not, then the same process is repeated again.
Decryption Process
The decryption Process for Advanced Encryption Standard is the same as Encryption Process for Advanced Encryption Standard but is always performed in reverse order. The four different subprocesses involved are as follows:
 Round Key Addition
 Column Shuffling
 Row Shifting
 Byte Substitution
The encryption and decryption processes are carried out separately since subtasks are carried out in reverse order.
FAQs

What is the size of the block in the Advanced Encryption Standard?
The size of the block in Advanced Encryption Standard is 128Bit.

What is the size of the key in the Advanced Encryption Standard?
The size of the key in the Advanced Encryption Standard is 128, 192 or 256 Bits.

How many iterative rounds does Advanced Encryption Standard 192 perform?
Advanced Encryption Standard 192 performs 12 rounds.

How many iterative rounds does Advanced Encryption Standard 256 perform?
Advanced Encryption Standard 192 performs 14 rounds.

What are States in AES?
The 4*4 matrices in the Advanced Encryption Standard algorithm are called States.
Key Takeaways
Congratulations on finishing the blog!! After reading this blog, you will grasp the concept of the Advanced Encryption Standard.
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