What is Advanced Encryption Standard (AES)? - Definition & Overview

Instructor: David Gloag

David has over 40 years of industry experience in software development and information technology and a bachelor of computer science

In this lesson, we'll take a look at the Advanced Encryption Standard (AES), its purpose, its basic characteristics, and its strength. At the end of this lesson, you should have a good understanding of the fundamentals of this technology.

What Is AES?

The Advanced Encryption Standard is everywhere, and you don't even know it. When you fill out forms online for the government (passport applications, drivers license renews, etc.), when you store personal information on a website (Facebook, Twitter, etc.), and even when you use your VISA or bank card to make a purchase, it is in the background, doing its thing.

Why? Because in today's day and age, security is paramount, and protecting information is a significant part of security.

Advanced Encryption Standard (AES) is a cipher, meaning that it is a method or process used to change raw information (usually human readable) into something that cannot be read. This part of the process is known as encryption. The method uses a known, external piece of information, called a key, to uniquely change the data. An example might be your computer login password, or the password to your account on a bank machine. Further, the process is reversible, meaning that it can be applied again to put the information back into its original form. This part is known as decryption.

Typical Uses

AES was released in 2001 by the National Institute of Standards and Technology (NIST). Its main purpose is to protect important information. In other words, hiding the information from unauthorized eyes. As a general example, a person may use it to transfer information from one location to another or secure that information for storage. As you might imagine, this has many specific applications. Personal data archival on home computers, software packages of various types, and military communications, are but a few.

Basic Characteristics

When used, the cipher breaks the data down into pieces, called blocks, of 128 bits in size. The key it uses can vary in length. 128, 192, or 256 bits are the current choices. The cipher uses the same key to encrypt and decrypt the information, another way of saying it is symmetric. It uses a sequence of simple calculation steps to transform (encrypt or decrypt) the data. The reason for this is so that the transformation can be performed quickly. Even with this, a data set of any size would take too long to transform by hand. Most implementations use special hardware of some sort or computers.

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