Advanced Encryption Standard

What is Advanced Encryption Standard

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PUREVPNPureVPN UpdatesWhat is Advanced Encryption Standard

About AES

Advanced Encryption Standard, also known as Rijndael, was established back in 2001 by the United States’ National Institute of Standards and Technology (NIST) to secure the sensitive data of all kinds usually implemented on the software and hardware throughout the world.

NIST then came up with an advanced encryption algorithm known as a block cipher which is chosen based on the following features:

  • Cost

The cost is intended to be released on a royalty-free basis globally, and the algorithms are evaluated based on its memory efficiency, which makes it cost-effective.

  • Security

The AES algorithm is evaluated based on its ability to resist an attack in comparison with other ciphers. The security has to be the most important strength of the AES algorithm.

  • Implementation

The implementation of the AES algorithm is evaluated on the basis of its flexibility, suitability, and how well it is implemented on the hardware and software that could cover the overall evaluation of the algorithm process implementation.

Learn about PureVPN’s 256-bit encryption.

Process of AES

AES is a complex process, but once the data goes through this process, the original content comes out in a code language that is understandable only by the computer. For example, if you have written ‘I need to go to school tomorrow,’ then the data would show something like “ok23b8a0i3j 293uivnfqf98vs87a”.

This shows that once the data is secured with AES, it comes out in the form of a random string of different characters, which is made on the basis of mathematical operations applied to the content. The content can only be understood by the system.

Here is how the AES process takes place:

Step 1: Key expansion

The AES key expansion algorithm takes as input a four-word (16-byte) key and produces a linear array of 44 words (176 bytes). This is enough to deliver a four-word round key for the initial AddRoundKey stage and each of the ten rounds of the cipher.

Advanced Encryption Standard

Step 2: Byte substitution

Each point of the data is changed based on a predetermined table, and this is the most crucial role of the Advanced Encryption Standard.

Byte substitution

It helps in altering the data in a non-linear format, which creates confusion for the other person when reading the information. This helps in hiding the data and creates a secured relationship between the original content and the encrypted data.

Step 3: Shift rows

This step is also critical. This helps in transposing the data to add more complications to it. The data is moved from its originality to obscure it further by shifting rows and altered in a horizontal way.

shift rows in aes

Step 4: Mix Columns

This step works exactly like shift rows, and the only difference is that the data is moved horizontally instead of moving it vertically.

mix column in aes

Step 5: Add round key

This is the last step in which a new round is derived from the initial key, which helps in adding greater confusion to the data, which makes it even more secured.

add round key in aes

Is AES Good Enough?

In today’s digital age, private data is transmitted online, which is where AES jumps into play. AES has been playing a critical role in defending our online security since 2001.

Over the years, AES has become much more reinforced by adding keys, shifting rows, mixing columns, and byte substitution, making it one of the essential tools for online data security. Irrespective of the fact that AES gets multiple attacks such as current potential side-channel attack and theoretical attack, AES remains secure.

AES is the most useful and highly recommended standard for data security and is applicable in different situations where sensitive data needs to be electronically transferred. AES should be used without any concern since it is the safest technique in the current level of technologies and attack techniques.

Advantages of Advanced Encryption Standard

At a very basic level, encryption helps in encoding the information so that only those who have access to the information can decrypt the data to understand it. For all those who don’t have the access key, the data will be gibberish in nature.

With the key, all the random characters are then turned into its original content. Encryption is very important and used almost everywhere, such as:

Government and Militaries

Advanced encryption standard is used by governments and militaries across the globe to ensure their national security information doesn’t land in the wrong hands. The US government widely uses AES by default since a large share of personal and work dealings are done online, so all the electronic data has to be protected with the highest military-grade encryption.


Banks use encryption for obvious reasons – securing the confidential data of their customers. Without encryption, the personal information of clients and the banks itself would be much easier for people to intercept, especially for cybercriminals and fraudsters.

Personal Information

Not just organizations, everyday people use encryption for their personal use as well. Encryption helps internet users conceal their valuable information in a way that only those who have the authorization key can have access.

The reason why encryption is one of the most vital tools today is that our modern-day infrastructure requires encryption to secure our processes. With data being transferred through electronic mediums, security is paramount, which is why AES plays a vital role.

Security Issues Discovered in AES

It is of great importance that cryptographers analyze any weaknesses in AES and come up with better technologies to be one step ahead of cybercriminals and hackers. Since its inception, here are a few side attacks that have come to light:

Known key distinguishing attack

A known key distinguishing attack was discovered back in again 2009 against the eight-round version of AES-128. Under this attack, an attacker who knows the key can find a structural property in cipher. It is not something to worry about by everyday internet users since it was only against the eight-round version of AES-128.

Related key attack

A series of related key attacks were discovered back in 2009. According to security experts, such attacks occur when AES is not implemented properly, and cipher operates under different keys. However, today’s AES doesn’t have this issue as the issue has been fixed.

Side-channel attack

This occurs when the information from the system is leaked. In this kind of attack, the attackers closely observers timing, sound, and other related information before breaching. If the algorithm of AES is carefully implemented, then this type of attack can easily be prevented by ensuring that there is no link between the leaked data and the AES processes.

Virus detection

AES doesn’t warn you if you’ve got a virus on your device. If you look at it, its purpose isn’t to notify the user about viruses, and we’ve got anti-virus software for that purpose. Since AES doesn’t provide virus detection capability, you should always have anti-virus software installed on your device for maximum protection against malware.

Attacks on AES

In the early years of AES, the security algorithm was often cracked and subject to intense scrutiny. If you look at it, those very attacks and ethical hacking practices made it secure for us today.

Had AES not been hacked and integrated with security patches, it wouldn’t be considered as a secure medium for encrypting the most confidential data. Moving from 64-bit encryption to 128-bit and now 256-bit, AES has had a long ride.

Just cracking the AES algorithm on the 128-bit key could take billions of years. The only kind of attack that could potentially come close to cracking AES is known as a Side-Channel Attack. This kind of attack is done based on the information gathered through the physical implementation of a cryptosystem and can still exploit the AES system.

Like any other algorithm, here are few of the potential weaknesses AES faces:

  • Timing attack – The attacker physically measures how often various computations are performed on the system.
  • Power monitoring attack – The attacker observes the various power consumptions by hardware during the computation in the system.
  • Electromagnetic attack – The attacker focuses on the leaked electromagnetic radiation that helps them in getting all the related information, and then use this information to identify similar keys designed by the AES algorithm.

Why Cipher was chosen for AES

As with any other encryption standard, there have always been trade-offs. The standard that was exponentially more secure than AES was easily available, but it took a long time to encrypt and decrypt data, which isn’t practical.

Therefore, block cipher was chosen by NIST, which could cater to all the abilities, including the effectiveness of its performance for both hardware and software, and also made the implementation of encryption standard easier while maintaining its high level of security.


With the increasing ratio of cyber-attacks on the rise, it is imperative that you have a system that can keep your valuable information safe and far away from prying eyes. AES helps in maximizing the digital security of your online information and mitigating any vulnerabilities towards online attacks.

PureVPN offers AES 256-bit encryption and other pristine features. PureVPN’s self-engineered and self-optimized VPN network ensures the highest secrecy of your online activities. Once connected with PureVPN, you can rest assured about your online privacy and security.




June 20, 2023


1 year ago

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