What is AES Encryption and How Does It Work? [Detailed Guide]

Today, we live in a world of data where humans produce around 2.5 quintillion bytes of data every day. From my perspective, that is 2.5, followed by 18 zeros. With data being produced daily, there are bound to be security issues.

Experts estimated the cost of an average data breach in 2021 to be around 4.24 million US dollars. The more alarming trend is that this cost has risen by 10% since 2019.

These are the times when you need robust security systems. A strong encryption system is the bedrock of a robust digital security system.

How Secure is AES Encryption?

The AES encryption algorithm is hard to crack. How hard? Experts estimate that breaking the encryption of AES with a brute-force attack would take more than 100 trillion years, even for the fastest supercomputer in the world. Even Quantum computers will take at least six months to break an AES algorithm.

Many experts consider AES one of the most secure encryption algorithms ever created. The creators of AES have made it publicly available. This creates suspicion in many people’s minds about how secure an algorithm can be if it’s open source.

Another way of looking at this is that the algorithm makers are so confident that they released it to the public. Another thing worth noting is that most organizations, from federal agencies to the military, still use the AES encryption standard.

If they stop using it, we might think something is wrong. However, their continued use of the AES algorithm in cryptography suggests that everything is fine.

What is AES Encryption?

The Advanced Encryption Standard, or AES, is a method for encrypting data in a way that is much stronger than traditional methods. The first version of the standard was released in 1996, and experts have improved it several times since then to meet today’s data security requirements. 

The basic premise of the AES standard is to use a series of rotations and substitutions to transform plaintext data into ciphertext. We know this process as encryption.

AES is a symmetric algorithm that uses the same key for encryption and decryption. It originated as a design for military and government use. The key size is usually 128 bytes (16 bits) and is typically changed infrequently to provide maximum protection against brute force attacks.

The National Institute for Standards and Technology(NIST) is the government organization responsible for publishing and maintaining AES. AES is one of the many NIST-issued federal information processing standards. The US Secretary of Commerce approves all these standards before publication.

The National Security Agency (NSA) approves AES as the sole block cipher for transmitting secret information across government agencies.

The AES encryption algorithm has become the cryptographic technology for people who want to encrypt their data securely. Federal government agencies, as well as non-government agencies, use AES encryption daily to protect their sensitive data.

The following Is a graphical illustration of the AES algorithm at work

A sender sends a plain text file to an encryption server. We use an AES secret key on this server to encrypt the plain text data into ciphertext data. The receiver of the file can only read the contents of the file if he has the secret key to open the file.

Why Was the AES Encryption Algorithm Necessary?

The DES (Data Encryption Standard) encryption algorithm was the predecessor to the AES encryption algorithm. While it sufficed for the needs of the generation of computers when it was created, with every passing year, hackers found it increasingly easy to break into the DES algorithm. We have shown that in the below image.

Thus, the need for a more robust encryption algorithm arose. The security researchers first tried creating a triple DES algorithm. The things that did not work out as planned as the base of this algorithm was excruciatingly slow.

Hence, the researchers went in a new direction and created an altogether new algorithm. AES has more extended key sizes and stronger ciphers than the DES algorithm.

Also Read: DES vs AES : Difference to Know 

Benefits of the AES

Here are some of the significant benefits of using the AES algorithm:

• Engineers can implement the AES algorithm in both software and hardware.
• The AES algorithm, being open-source, allows private and public sectors to access it.
• The AES algorithm is extremely resilient against hacking attempts.
• The AES encryption algorithm is the most widely used security protocol today.

How does AES Encryption Work?

Here is a brief overview of how the AES encryption mechanism works. AES is known for its central design principle, the substitution permutation network. The substitution permutation network refers to a series of mathematical operations linked with each other.

The network works by applying many layers of substitution and permutation boxes to play in the text. This process produces the cipher text block. The ciphertext is an unreadable conversion of plain text data. Humans cannot read the AES ciphertext until they use the correct AES key to decrypt the data.

AES has three key sizes

• 128
• 192
• 256

Although the critical length of the AES encryption algorithm varies, the block size is always 128 bits. Many of you might wonder why there are different key lengths. Many of you might also question whether the 256-bit key is the strongest of the lot, so why don’t we use this single key instead of the other two?

The thing is, there are resource constraints. For instance, if you have a mobile app that uses AES-256 instead of AES-128, then it will drain the phone’s battery faster.

Hence, if your app does not require a higher level of encryption, it is best to use a lower level to save on resources utilized.

Example of how AES encryption looks like:

Can you decipher the following ciphertext message?

bWhVOg5IxuiUw1TKrEjFD4CCw9r30KcSp8LU49JXX89i5+K/Z55QeNgPnEoDtK90bbUjpbQZ/yaQGOdXlbZS9/Ntd/mfxnK6GAhyKmtHUUk=

No? Thought so. Here is the plain-text version

Plaintext message: Doctors diagnosed the acting president with a potentially terminal illness.

You can only decipher the message with the correct AES encryption key.

Examples of AES Encryption

Many everyday uses of the AES algorithm exist today, not just limited to Federal agencies employing it. It may surprise you that many solid-state drives (SSDs) already utilize the AES encryption algorithms.

This ensures that the data is encrypted and protected when the SSD is produced in the factory.

• Many SSD manufacturers equip their hard drives with 256-bit AES hardware-based encryption, keeping hackers out of the equation.
• Virtual private networks, or VPNs, popularly utilize the Pratik encryption standard to securely connect you with another server, typically located in another country.
  
  As VPNs have to switch between servers dynamically, they can afford to use only the best encryption methods. Popular VPN services like NordVPN and ExpressVPN use the AES-256 bit key to secure their customers’ browsing data.
• Your social media messages are also encrypted. So that you do not need to worry about someone reading your messages and extracting critical information about you from those messages.
  
  The popular social media messaging platform WhatsApp employs the AES algorithm. WhatsApp encrypts its messages using 256-bit AES encryption. This makes it extremely difficult for hackers to hack into your WhatsApp messages.
• The world’s favorite desktop operating system, Windows, also uses AES 128-bit and 256-bit encryption.
• All data stored in Google Cloud is encrypted using a 256-bit AES encryption by default.
• LastPass is one of the most famous password management applications. LastPass uses AES encryption. The AES encryption helps LastPass to keep the user’s password safe from hackers. Even Lastpass employees cannot access users’ passwords.
• The US military, national security agencies, and other US government entities use AES encryption to secure data storage.

A classic example of AES encryption in action is your internet browser. Whenever you visit a website with https in its URL, a TLS / SSL certificate likely secures it. This means that the website uses AES encryption to maintain the security and integrity of your browsing sessions.

Another everyday use of the AES algorithm is in Wi-Fi. Wi-Fi is secured by WPA2-PSK (AES) encryption. Even Facebook Messenger uses the AES encryption standard.

Final Words

The AES encryption standard has become the gold for encrypting sensitive data across various applications. If you are considering building an app that deals with sensitive data, then it is best to consider the security mechanism the app will have.

The AES encryption standard is one of the many robust encryption standards available. Select the most appropriate encryption standard to ensure your app performs optimally. You can take expert opinion for this.

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