AES: How to Design Secure Encryption

In 1997, a contest began to develop a new encryption algorithm to become the Advanced Encryption Standard. After years of debate, one algorithm was chosen as the AES. But how does AES work? And what makes for a secure encryption algorithm?

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0:00 The Contest
1:02 Encryption
3:57 Confusion and Diffusion
5:44 Block Cipher
6:55 KeyExpansion
7:34 AddRoundKey
8:14 Substitution Cipher
8:55 SubBytes
11:30 MixColumns
12:53 ShiftRows
13:21 The Algorithm

[joirnpettersen]

It would be really interesting to explain some of the candidates that didn't make it. For example show why some of the rejected algorithms weren't secure.

[LukPlys]

Finally a simple enough yet comprehensive explanation of AES. I always wondered how this algorithm worked and you layed it out so well!

[phunanon]

The use of the little robots is so engaging! SubBytes is oddly adorable in their mannerisms :D

[aprilmintacpineda]

The clever use of graphics to illustrate the processes elevates the learning experience to a whole new level! Very well done!

[stephenj]

Such a little thing, but the ability to portray so many emotions and reactions on the robots' simple faces is a nice touch. Looking down when we run into a problem, tilting the head when someone new is introduced, etc.

[MarekKnapek]

Great! Now continue with why simple AES encryption (ECB) is not enough in case of messages longer than 128bits. That's why cipher mode such as CBC exists.

[erkinalp]

The underlying round function of AES also has the nice property of generalisation, namely, it can easily be adapted to a public key one or a hashing function just by modifying how the key modifies the input in AddRoundKey.

[slowedreverb]

I can't say how grateful I am, cause I was breaking my head to find good videos which I could understand easily, algorithm like MD5 and Sha 256 which teaches me and not just the same old crap. Thank you ❤❤

[rileyn]

Great video! Very clear explanation. Would've loved to hear more about how key expansion works

[brandonmarks]

Best channel on youtube. Videos are always so clear and great subject matter.

[tksnail]

I love how you used 'robots' to describe functions, and the way you arranged them at the end!

[BritishBeachcomber]

Back in '95 I designed a password encryption algorithm based on XOR (exclusive or) logic. The company, AT&T NCR was sutilably impressed.

[Stvk]

this is like the only video explaining AES that i totally understand XD

Also the visualize with box make my brain learn faster

Good video as always, thanks you and the robots so much

[TomLisankie]

Your videos are consistently great. I wish you would do them full time.

[isarow]

I haven't posted a single comment for a few years probably, but this video works so well for me that I have to say - very good explanation and thank you for this vid :)

[FerventApathy]

You have no clue how helpful this is, and how extremely useful it is for what I work on. Thanks!

[Anythiny]

Loved that this guy has not stopped yet!! Thanku so much sir

[MichaelKubler-kublermdk]

This is the best explanation of AES I've come across.
Thank you so much for putting this together!

[vani_maki]

The best explanation of aes I've ever heard

[conradludgate]

Ironically almost all cipher modes still use one-time pads as shown in the beginning, and we use AES or other keyed mixing algorithms to generate a consistent but unique random key stream.

I guess it was concluded that diffusion of the plaintext isn't a useful property in the end. This only works securely if each message starts with a unique "initialisation vector" aka "nonce" though, to ensure each one-time pad sequence for each key-message pair is unique and can't be statistically analysed