AES – The Advanced Encryption Standard Explained

#cryptology, #cryptography, #cryptanalysis

In this video we discuss the Advanced Encryption Standard (AES) our current modern standard for symmetric encryption. AES is now older than 20 years but still very secure. All attacks found so far are only theoretical attacks. AES is the successor of the Data Encryption Standard (DES).

In the video, we discuss all building blocks (AddRoundKey, SubBytes, ShiftRows, and MixColumns). MixColumns is described but the "heavy math" is omitted. The details of the Key Expansion are also not shown. In future videos, we will also discuss MixColumns math as well as the Key Expansion in detail.

We also show the visualization of AES in CrypTool 2 as well as in CrypTool-online.

If you are interested in implementing AES on your own, we highly recommend the following wikipedia articles:

You find the AES visualizations in CT-Online here:

[timetraveller]

This was a very interesting demonstration. You made it sound so simple. I am inspired to try making a hand cipher based on some of the aes steps.

[antonyjohn]

The presentation in this video is very beautiful. Did you create a video that describes the properties of a good S-box?

[Lol-dtmw]

Best explanation man! Love from India💌

[roeyborovsky]

Amazing video. I wish I could have watched it before hours of research!

[paulocorreia]

Outstanding. Thank you for this video.

[giuseppecristiano]

Thank u a lot, it was very intrestring, i hope u ll make a video about the propieties of the s-box ! I ve written a program in c# implementing aes to encrypt a DB using the microsoft aes library . I wanted to learn deeper how aes works becouse i need to know in deteils how it executes step by step in order to understand how can i split the tasks in order to encrypt faster . Do u think that separate the backup file in more chunks written in temporary files and merge at the end them togheter in the right sequence
wouldn t work?

[mosesmulwa]

This was very good. It is simple once you understand it

[robertstarr]

I am taking a class focused on this right now, and it was immensely helpful! I tried to work through your MixColumns step, and I noticed that my result matrix is a transpose of your result matrix (the one labeled "New State" with the blue text color in the video around t=20:00). No transpose step was mentioned there - I am curious if something is in error? Using the green highlighted column of the input matrix "State" does not yield the blue highlighted column of the output matrix "New State", but rather it results in the values in the first row of the "New State" matrix. Such is true for the remaining columns. Just looking to ensure I have the correct understanding of the MixColumns step! Thanks again!

[KamiKze]

what's the default state? Before we change it?