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:
en.wikipedia.o...
en.wikipedia.o...
en.wikipedia.o...
You find the AES visualizations in CT-Online here:
www.cryptool.o...
www.cryptool.o...
If you are interested in learning the fundaments of cryptology, let me invite you to have a look at our video series about the basics of cryptology, also for beginners: • Basics of Cryptology -...
You can download the latest version of CrypTool 2 from here: www.cryptool.o...

[@timetraveller6643]

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.

[@CryptographyForEverybody]

Thanks :-) A hand AES would be nice :-) Greetings, Nils

[@Lol-dt1mw]

Best explanation man! Love from India💌

[@antonyjohn3804]

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

[@CryptographyForEverybody]

Hello, No, not yet :-). But we are working on S-Boxes (or how to analyze/view them) in CT2. When we finish that, I will also create a video about S-Boxes. But I cannot say when this is done. Are you just interested in that topic or did you yourself also already worked with ciphers/S-boxes? Greetings, Nils

[@paulocorreia4694]

Outstanding. Thank you for this video.

[@CryptographyForEverybody]

Thx, Happy that you like it :-) Cheers, Nils

[@roeyborovsky6324]

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

[@CryptographyForEverybody]

Thx, happy you liked it 🙂

[@giuseppecristiano9006]

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?

[@billcallahan218]

Outstanding!

[@robertstarr8585]

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!

[@CryptographyForEverybody]

Heyho, thank you :-) In the MixColumnsStep of AES you multiply each of the four columns of the state with the matrix and then you use the result of each of that multiplications as a new column. The four columns are then combined to form the next state (see also the article in Wikipedia about the MixColumnsStep: en.wikipedia.org/wiki/Rijndael_MixColumns). Greetings, Nils

[@mosesmulwa]

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

[@CryptographyForEverybody]

Thank you Moses Mulwa, And yes, you're right. Also, a good way to get a deep understanding is to also implement it once in a programming language of your choice. After I did that, I knew that I understood it 100%, Greetings, Nils

[@mosesmulwa]

@@CryptographyForEverybody I think I will do it in Python

[@akashelangovan6924]

Thank you for this video.

[@CryptographyForEverybody]

You are welcome 🙂

[@timetraveller6643]

Also, I must relearn matrix math.

[@peji6000]

Great video and teaching!

[@CryptographyForEverybody]

Thank you :-)

[@KamiK4ze]

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

[@CryptographyForEverybody]

The initial state is the plaintext before encryption or the ciphertext before decryption. The final state is the encrypted ciphertext or decrypted plaintext. Greetings, Nils

[@KamiK4ze]

@@CryptographyForEverybody ahh ok thank you!