Maximizing Security with AES Encryption: A Comprehensive Guide


As cyber-attacks become more sophisticated and frequent, it’s more important than ever to ensure that our electronic data is securely encrypted. 


In the past, older encryption methods were sufficient for protecting sensitive information, but they no longer meet today's security needs. That's where AES encryption comes in. 


Widely adopted as the standard encryption method, AES offers a high level of security and has become the go-to choice for encrypting sensitive data. In this guide, we'll dive into the details of how AES encryption works and the benefits it provides.

What Is the Advanced Encryption Standard (AES)?

The Advanced Encryption Standard (AES) is the encryption standard set by the U.S. National Institute of Standards and Technology (NIST) in 2001. It’s used to protect digital data by providing better security over other methods like DES. 

AES has existed for over 20 years. It was originally developed in 1998 by Vincent Rijmen and Joan Daemen, two Belgian cryptographers. In 2002, NIST replaced  DES with AES as the encryption standard. 

How Does AES Encryption Work?

The AES algorithm involves the use of a 128-bit symmetric block cipher to encrypt and decrypt information. During the encryption process, the AES algorithm converts plaintext (human-readable) data into unreadable ciphertext. To access the original plaintext, the ciphertext must be decrypted using the secret AES key.

What Are the Features of AES?

The features of AES include:

SP Network: 

Used for mixing and shuffling the data in the encryption process.

Key Expansion: 

Using a series of mathematical operations and table lookups to expand the key and to create a number of round keys.

Byte Data: 

Blocks in AES encryption are processed independently, with each block containing 128 bits (16 bytes).

Key Length: 

AES supports three key lengths: 128-bit, 192-bit, and 256-bit key lengths are supported in AES. Longer keys provide stronger protection.

Criteria for being chosen as the next AES algorithm included:


The algorithm's competence in protecting against attacks.


Algorithms with more efficient computation and memory requirements were favored.


Flexible Algorithms that could be suitable for software and hardware implementation were considered easier to implement.

Choosing the New AES Algorithm

In 1999, the National Institute of Standards and Technology (NIST) proposed five algorithms to be used in AES encryption. These were:

  • MARS: A block cipher developed by IBM Research.
  • RC6: A block cipher created by RSA Security.
  • Rijndael: Developed by Belgian cryptographers Joan Daemen and Vincent Rijmen.
  • Serpent: Created by Ross Anderson, Eli Biham, and Lars Knudsen. 
  • Twofish: Built by Counterpane Internet Security.

After the algorithms were tested and evaluated, the Rijndael algorithm was picked as the proposed AES in 2000, later evolving into a federal government standard.

Encryption Process

The AES encryption process consists of the following steps: 

  1. The plaintext is divided into blocks
  2. SubBytes: implements the byte substitution
  3. Shift rows: Each row is shifted a specific number of times
  4. Mix columns: matrix multiplication is performed, where each column is multiplied with a matrix
  5. Add round keys

The process is repeated multiple times, where the number of rounds corresponds to the key length. For example, a 128-bit key requires 10 rounds, while a 256-bit key requires 14 rounds.

Once the final round is complete, the final ciphertext is produced. 

Decryption Process

The AES decryption process is basically the reverse of the encryption process. It involves the following steps:

  1. The final round key from the encryption process is added to the ciphertext block
  2. Inverse mix columns: The columns of the block column are multiplied by the inverse of the matrix in the original encryption process
  3. Inverse shift rows: The rows of the block rows are shifted in the opposite direction
  4. Inverse byte substitution: The block bytes are replaced with values from the inverse of the Rijndael S-box 
  5. Repeat the above steps for each round
  6. Add the initial round key to the block to generate the plaintext

What’s the Difference Between AES-128 and AES-256?

Point of Comparison



Key Size

128 bit

256 bit

Number of Rounds





Very secure

What’s the Difference Between AES vs. RSA?

Point of Comparison






Key Size

128, 192, or 256 bit

1024, 2048, 4096 bits





More secure

Less secure

What’s the Difference Between AES vs. DES?

Point of Comparison



Block Size

128 bits

64 bits


More secure

Less secure

Key Size

128, 192, or 256 bit

56 bits

Key Expansion 


Not required

Attacks on AES Encryption

Possible attacks on AES encryption include:

  • Related-key attacks: These attacks are fast and easy to execute. They target the encryption key.
  • Side-channel attacks: These exploit data leaks and may succeed in case of poor AES implementation.
  • Known-key distinguishing attacks: These attacks may only work if the attacker knows the key, which is a remote possibility.
  • Key-recovery attacks: In key-recovery attacks, the hacker must have access to a minimum of one pair of encrypted/decrypted messages.

Is AES Secure? Does AES Encryption Have Any Security Issues?

To date, there have been no successful cyber attacks on AES encryption. When implemented correctly, AES encryption is impossible to compromise. 


Here’s how to get the best possible protection out of AES encryption and minimize risk

  • Use long, hard-to-guess passwords
  • Use Multifactor Authentication (MFA)
  • Utilize a password manager
  • Train employees on security best practices
  • Use firewalls and anti-malware tools

The Advantages of AES

Some of the perks of using AES encryption include:

  • Simple implementation 
  • Fast encryption and decryption
  • Robust security
  • Less memory-demanding than other types of encryption
  • Can be combined with security protocols like SSL and WPA2 for better security
  • Versatile key lengths

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Read more articles: 

What are the Different Types of Encryption? List you must Know

DSA Algorithm: An In-depth Overview