To me, this is by far the clearest explanation on AES algorithm described in very short time. I've been surfing on Google for few days reading a couple of articles , this video can beat most of those lengthy articles.
it's so crystal clear. I am so astonished as you were when you first saw the animation. So far it's the easiest way to understand and explain things I came across.
read this carefully: 1. we have a predefined matrix for AES which we use for every mix column operation: 02 03 01 01 01 02 03 01 01 01 02 03 03 01 01 02 this is predefined so you gotta remember it. 2. Take the predefined matrix and multiply it with the first word, followed by second, third and fourth word. But, this is not a standard multiplication here, it's something really different. The Galois multiplication of polynomial. Every position in the state matrix is a byte, meaning we have 8 bits in it. Now we consider the Galois polynomial multiplication in 8. Thus, we can't have any terms greater than x^7 coz 8 bits are represented as x^7 + x^6 + x^5 + x^4 + x^3 + x^2 + x^1 + x^0 for any terms that is greater than 8, we reduce it by the Galois irreducible polynomial of 8 bits, that is x^8 + x^4 + x^3 + x^1 +1. 3. Now convert each byte in a word into polynomial form: for d4 it is 1101 0100 =x^7 + x^6 + x^4 + x^2 multiply it with 02 coz 02 is the first element in the predefined matrix coz that's how you multiply in the normal matrix too... 02=0000 0010=x^1 4. 02*d4=x(x^7 + x^6 + x^4 + x^2)=x^8+x^7+x^5+x^3 Since this is greater than 8 bits we reduce it by the irreducible polynomial... divide x^8+x^7+x^5+x^3 by x^8 + x^4 + x^3 + x^1 +1 and the remainder is your answer. 5. perform this for the rest 3 values. X-or all of them and the result is your answer for 1st position in the matrix. 6. Perform all these steps until you find the answer. This is why it is infeasible to decipher anything encrypted with AES manually.
x^8+x^7+x^5+x^3 by x^8 + x^4 + x^3 + x^1 +1 = 1A8 divided by 11B = 1 remained 8D, right? Then 03 * BF divided by 11B has the remainder of 07, 8D XOR 07 XOR 5D XOR 30 gives D7 not 04. Could you please explain how he got 04?
This is a very clear explanation of AES Rijndael Cipher but my question is how do you build the S-Box and the RCon tables ? It is somehow random (by design ?) or it has some other algorithm ? Also how do you get the matrix for the Rijndael Galois field ? because my problem is that if you use the same S-Box and Rcon you create a complex pattern of diffusion that can give away information (leak) about the cipher. Also is it possible to add more rounds ? or make the number of rounds change after each plaintext block is processed ? This is great stuff. Very nice job explaining this.
I'm not sure whether I'm understanding it correctly or not: When using a 256 bit key, do I just have to turn each "4 positions earlier" into an "8 positions earlier" and apply the rules at 3:23 to each word that is a multiple of 8 instead of 4? Furthermoe there's obviously a gap between key length and block length, so is each round key basically a derivation of a half of the original key? I would be soooooooooo happy and thankful if you could help me here. Im pretty confused and the original source "The Design of Rijndael" is incredibly hard to understand for me because of it's abstract nature. :(
I am only the chap who recorded the Flash animation as a video, so don't expect AES expertise from me :) I think this thread on SO (crypto.stackexchange.com/q/2486) explains the effects of key size on the key schedule quite well.
@@AppliedGo Thank you for your answer! :) I'am actually thorugh it now. :D One day I finally surrendered to the fact that I will have to work through the formulas of the key expansion because I could not find any animation or graphic that explains it an easy way. So I equipped a pen and lots of paper and started to translate each formula step by step into easy words and graphics. After a few hours I ended up with a huge graphic that shows the start of the content of the expanded key and several graphics and texts that explain each of the four rules for the key expansion. I develop a software for my master thesis, which uses AES. That's why it was important for me. :) I'll maybe explain it later under this video to help other people when I have more time. :)
I'm getting the same values, except for the last Round key (10), instead of d0 c9 e1 b6 14 ee 3f 63 f9 25 0c 0c a8 89 c8 a6 ... I'm getting ... e6 54 e5 49 13 d6 82 fc 60 4e f1 a4 24 9d 40 ef Sigh! Thanks for the awesome video! I'm getting closer! :D
in mix column, Galois field is used to multiply. Search Galois field in TH-cam. Here addition is xor, multiplication is modulus. Watch the below video to get an idea: th-cam.com/video/O4xNJsjtN6E/w-d-xo.html&ab_channel=Computerphile
No, as mentioned in the description, there is no audio track. I am just clicking through the flash app, to preserve it for the times when the very last flash player will have died.
I am not an AES expert - see the video description. I just recorded this click-through at a time when Flash animations were still working in browsers, to preserve this awesome work for the future.
short answer: prior to the encryption long answer: it depends on which mode you are using 👇 - *If you are using ECB or CTR* , no IV is required - *If you are using CBC* , the IV is XORed with the message before it is passed to the encryption rounds - *If you are using CFB* , the IV is passed through the encryption rounds and the original message is XORed with the encrypted IV
Sorry, I cannot comment on the details. This animation is not from me. I only preserved it as video because the Flash format is obsolete. See the video description for more details. I should have made this clear in the video itself, not only in the description.
Good question. I only recorded the original Flash animation to save it for the post-Flash era, so I cannot comment on the implementation details. (BTW, recently someone created a new interactive HTML5/JS based version, see the video description for details)
I did not do this myself. This is just a "click through" I did to preserve that Flash animation when Flash will not be available anymore. See the video description for more details.
To me, this is by far the clearest explanation on AES algorithm described in very short time. I've been surfing on Google for few days reading a couple of articles , this video can beat most of those lengthy articles.
I completely agree!
same here!!
it's so crystal clear. I am so astonished as you were when you first saw the animation. So far it's the easiest way to understand and explain things I came across.
this is the best video on the internet. nothing compares to this.
read this carefully:
1. we have a predefined matrix for AES which we use for every mix column operation:
02 03 01 01
01 02 03 01
01 01 02 03
03 01 01 02
this is predefined so you gotta remember it.
2. Take the predefined matrix and multiply it with the first word, followed by second, third and fourth word. But, this is not a standard multiplication here, it's something really different. The Galois multiplication of polynomial. Every position in the state matrix is a byte, meaning we have 8 bits in it.
Now we consider the Galois polynomial multiplication in 8.
Thus, we can't have any terms greater than x^7 coz 8 bits are represented as
x^7 + x^6 + x^5 + x^4 + x^3 + x^2 + x^1 + x^0
for any terms that is greater than 8, we reduce it by the Galois irreducible polynomial of 8 bits, that is x^8 + x^4 + x^3 + x^1 +1.
3. Now convert each byte in a word into polynomial form:
for d4 it is 1101 0100 =x^7 + x^6 + x^4 + x^2
multiply it with 02 coz 02 is the first element in the predefined matrix coz that's how you multiply in the normal matrix too...
02=0000 0010=x^1
4. 02*d4=x(x^7 + x^6 + x^4 + x^2)=x^8+x^7+x^5+x^3
Since this is greater than 8 bits we reduce it by the irreducible polynomial...
divide x^8+x^7+x^5+x^3 by x^8 + x^4 + x^3 + x^1 +1 and the remainder is your answer.
5. perform this for the rest 3 values. X-or all of them and the result is your answer for 1st position in the matrix.
6. Perform all these steps until you find the answer.
This is why it is infeasible to decipher anything encrypted with AES manually.
Thank you.
why we divided by x^8 + x^4 + x^1 + 1?
@@fauzanraeva4806 title says "read this carefully"
> the Galois irreducible polynomial of 8 bits, that is x^8 + x^4 + x^3 + x^1 +1.
x^8+x^7+x^5+x^3 by x^8 + x^4 + x^3 + x^1 +1 = 1A8 divided by 11B = 1 remained 8D, right?
Then 03 * BF divided by 11B has the remainder of 07,
8D XOR 07 XOR 5D XOR 30 gives D7 not 04.
Could you please explain how he got 04?
Thanks for the detailed explanation. Now I understand the concept much better :)
I'd been trying to understand the AES for months... until today. Thank you so much for sharing this animation!
My God. In such a short time, such an excellent illustration. Hats off!!!
Great complement to the written descriptions of AES! Helped me to catch a couple steps that I misunderstood.
Holy carp that was a clean, concise and beautiful explanation
This is the best explanation of AES ever. Thank you.
Really appreciate for this fantastic animation. 💗
best explaination on aes algorithm.
This is the clearest explanation I've found and it turned out to be the shortest 😂
This is a very clear explanation of AES Rijndael Cipher but my question is how do you build the S-Box and the RCon tables ? It is somehow random (by design ?) or it has some other algorithm ? Also how do you get the matrix for the Rijndael Galois field ? because my problem is that if you use the same S-Box and Rcon you create a complex pattern of diffusion that can give away information (leak) about the cipher. Also is it possible to add more rounds ? or make the number of rounds change after each plaintext block is processed ? This is great stuff. Very nice job explaining this.
Welcome to the the post-flash world ;)
Very nice video. Helped a lot to understand the working of AES.
I now found the simplest answer to my question, I mean the best out of all my findings. Thanks
THIS HELP ME SO MUCH!!! THANKS!!!
Amazing video, thank you so much!
Key shedule. Notice, that first round constant (rcon) is (01 00 00 00), then it disappears from yellow table and appears in XOR
Best explanation I've seen so far
Thanks for illustration that is great
Nicely done.
that's amesome!! thank you very much
that is great. but why is the state block's numbers different by plaintext's numbers before starting subByte step?
Thanks for this animation, it was very simple to understand :))
Thank you so much, this helped me alot!!
what an amazing video, great work ,
Note that this is just a recording of a Flash animation, all I did is clicking at the right moment - see the video description.
Thank u🙏.. It helped me to understand the process
I'm not sure whether I'm understanding it correctly or not:
When using a 256 bit key, do I just have to turn each "4 positions earlier" into an "8 positions earlier" and apply the rules at 3:23 to each word that is a multiple of 8 instead of 4? Furthermoe there's obviously a gap between key length and block length, so is each round key basically a derivation of a half of the original key?
I would be soooooooooo happy and thankful if you could help me here. Im pretty confused and the original source "The Design of Rijndael" is incredibly hard to understand for me because of it's abstract nature. :(
I am only the chap who recorded the Flash animation as a video, so don't expect AES expertise from me :)
I think this thread on SO (crypto.stackexchange.com/q/2486) explains the effects of key size on the key schedule quite well.
@@AppliedGo Thank you for your answer! :)
I'am actually thorugh it now. :D One day I finally surrendered to the fact that I will have to work through the formulas of the key expansion because I could not find any animation or graphic that explains it an easy way. So I equipped a pen and lots of paper and started to translate each formula step by step into easy words and graphics. After a few hours I ended up with a huge graphic that shows the start of the content of the expanded key and several graphics and texts that explain each of the four rules for the key expansion. I develop a software for my master thesis, which uses AES. That's why it was important for me. :) I'll maybe explain it later under this video to help other people when I have more time. :)
@@dasnachtgespenst Awesome! Now turn these graphics into an animated video and share it here! :-)
Thank you so much it’s useful
thank you very much that's very useful
it was very insightful thanks
Thanks man!! Was very helpful
This is great, thanks!
it's very very helpful and good video thank U so much
awesome vid bro. thx alot.
Where is the sound?!!!!
Very nice, thank you
I'm getting the same values, except for the last Round key (10), instead of
d0 c9 e1 b6
14 ee 3f 63
f9 25 0c 0c
a8 89 c8 a6
... I'm getting ...
e6 54 e5 49
13 d6 82 fc
60 4e f1 a4
24 9d 40 ef
Sigh! Thanks for the awesome video! I'm getting closer! :D
hi, is there any details explanation on how to do the mix column part.step by step
hit the comment button please
Thank you
in mix column, Galois field is used to multiply. Search Galois field in TH-cam. Here addition is xor, multiplication is modulus. Watch the below video to get an idea:
th-cam.com/video/O4xNJsjtN6E/w-d-xo.html&ab_channel=Computerphile
amazing
Hi,May I ask what the plaintext is?
Good job 👏 thanks 😍
AES explanation with flAES animation
Easy to understand through graphics...
Great explaining!
thank you so much
Thank you so much
excuse me, what if my hexa was e only. is it stays as it is on the Sub Byte s table?
It looks like it would be good.. but is there supposed to be sound??
No, as mentioned in the description, there is no audio track. I am just clicking through the flash app, to preserve it for the times when the very last flash player will have died.
真的讚讚讚的說，馬上按個讚的說
How do we Program it in Python?
wow great video💚
i wonder , can we create our own algorithm by changing s-box table , how can we do it. if we do it random , do it work ?
Where does the IV come into this?
I am not an AES expert - see the video description. I just recorded this click-through at a time when Flash animations were still working in browsers, to preserve this awesome work for the future.
short answer: prior to the encryption
long answer: it depends on which mode you are using 👇
- *If you are using ECB or CTR* , no IV is required
- *If you are using CBC* , the IV is XORed with the message before it is passed to the encryption rounds
- *If you are using CFB* , the IV is passed through the encryption rounds and the original message is XORed with the encrypted IV
Can you explain round key and key schedule in more depth
Sorry, I cannot comment on the details. This animation is not from me. I only preserved it as video because the Flash format is obsolete. See the video description for more details. I should have made this clear in the video itself, not only in the description.
Why is key expansion different than the actual AES?
Good question. I only recorded the original Flash animation to save it for the post-Flash era, so I cannot comment on the implementation details.
(BTW, recently someone created a new interactive HTML5/JS based version, see the video description for details)
Quite useful, thanks :)
Rotate right or left???
عندي Midterm باجر وانا مب فاهم هالدرس :) الله يستر بس
يارب انجح وافتك من هالمادة cryptography ....
YOU BEST!!!!!!!!!!!!!!!!!!!!!!!!!!
Note that this is just a recording of a Flash animation, all I did is clicking at the right moment - see the video description.
what is plain text and key you used? and which mode you use?
I did not do this myself. This is just a "click through" I did to preserve that Flash animation when Flash will not be available anymore. See the video description for more details.
that was really good cleared my though aes.
Totally Agree!
Briliant
Thank you@@
Profu de Bc2 sa traiti🎉🎉🎉
super
Came here from a Cryptohack's lesson. Great video.
cool bro
@S3TI
AES with Example in hindi
fajny film
coooooool
based
wstyt prawicy
jednak mi sie nie podoba
ze wam tak po prostu po lucku nie wstyt
Ndak bisa basa enggres