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What is AES, the Advanced Encryption Standard?

What is encryption?

A message has the power to change your life, and it is usually personal or confidential. The science of cryptography involves substituting letters with other characters to conceal the original message. Cryptography protects data by encrypting it with a code, or cipher, that the intended recipient can only decipher. Encryption is employing a mathematical technique to turn data into scrambled information that a receiver with a key can only read.

We use encryption for several purposes, including the security of sensitive data and financial transactions. Weak encryption has the potential to be fatal. Allied Powers, for example, cracked Nazi codes during WWII, causing the Germans to lose the war.

How does encryption work?

Encryption is transforming data into a code before delivering it over the internet. The code can be deciphered and transformed back into the original data once it arrives at its destination. Encryption is a technique for safeguarding sensitive data delivered across a network. Emails, credit card numbers, and anything else transferred digitally can be encrypted to prevent it from being read by anyone intercepting it on its way to its intended recipient.

What is AES encryption?

The AES algorithm encrypts data, rendering it unreadable to hackers and others attempting unauthorised access. At least not in our lifetime. The AES algorithm is unbreakable. Even a 128-bit AES key would take billions of years for a supercomputer to crack. As a result, it has established itself as one of the best standard for protecting electronic data and classified information from unauthorized access.

The United States National Institute of Standards and Technology (NIST) developed the Advanced Encryption Standard (AES) in 2001. This encryption standard replaced DES, which had length limitations. AES uses a 128-bit key, which is larger than the 56-bit key used by DES.

How does it work?

AES encrypts electronic data using 128-bit, 192-bit, or 256-bit symmetric encryption method. An encryption server encrypts a plaintext file or converts it to ciphertext using an AES secret key. The same secret key is used to decrypt the contents.

The AES encryption algorithm operates as follows:

Initially, data is organised into 128-bit blocks, or four-by-four columns of 16 bytes. A byte contains eight bits, multiplying 16 by eight results in a block size of 128 bits.

After that, it goes through the following interesting changes:

Rijndael's key scheduling: Each consecutive round of encryption generates fresh keys, known as round keys.

Round key addition: Here, the first round key is added to the divided data.

Byte substitution: Rijndael S-box substitution box to replace each byte with a different byte.

Row shifting: The second row takes one space to the left, two spaces to the left for the third row, and three spaces to the left for the fourth row of the divided data.

Column mixing: A pre-determined matrix to multiply the columns of divided data and generate a new code block.

Round key addition: Another round key to the mix of columns.

The method is repeated after the first round. There are 10 transformation rounds in 128-bit AES encryption, 12 in 192-bit AES encryption, and 14 in 256-bit AES encryption.

What is 128-bit AES encryption?

The method of encrypting plaintext data with a 128-bit AES key length is known as 128-bit AES encryption. To convert plaintext to ciphertext, 128-bit AES encryption employs ten transformation rounds.

Why is it required to have 192-bit or 256-bit AES encryption if 128-bit AES encryption would take billions of years for a supercomputer to break?

For most users, 128-bit AES encryption is more than enough for securing sensitive data, but when top-secret data is involved, even if the probability of a breach is low, government agencies are hesitant to face the danger of top-secret data being compromised. As a result, they opt for higher AES key lengths, which provide more security and a broader brute-force search space, which is especially important given the threat of quantum computing attacks.

Nowadays, 256-bit AES encryption is the most used encryption method, as many developers and manufacturers, like IBM and others, use it by default.

Who use AES?

Government departments, agencies, as well as non-government institutions and commercial firms and organisations use AES encryption to protect sensitive data on a regular basis. Consumers, too, frequently use AES-encrypted gadgets without realising it.

Many devices, applications, and networks in use today, such as solid-state drives (SSDs), hard disc drives (HDDs), WiFi in local area networks (LANs), securely engineered firmware images, cloud computing storage, internet browsers, and website TSL/SSL certificates, use AES encryption.

AES encryption is used by Samsung, Micron, WhatsApp messaging, and Google Cloud, Microsoft Windows' BitLocker and the Trusted Computing Group (TCG). LastPass, a password management service, encrypts its users' passwords with AES encryption to keep them safe from hackers.


Symmetric encryption uses the same key for both encrypting and decrypting data. Asymmetric encryption employs two distinct keys, one for encrypting data and the other for decrypting it. AES (Advanced Encryption Standard) is a symmetric technique that converts plaintext to ciphertext by encrypting it with a secret key. When the same secret key is used to decrypt the contents of the encrypted file, the intended recipient can read the contents of the file. the AES algorithm is unbreakable. Even a 128-bit AES key would take billions of years for a supercomputer to crack.


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