Stick Guide
User Manual: Pdf
Open the PDF directly: View PDF 
.
Page Count: 45
| Download | |
| Open PDF In Browser | View PDF |
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
Moserware
About
A Stick Figure Guide to the Advanced
Encryption Standard (AES)
Sep 22, 2009
(A play in 4 acts. Please feel free to exit along with the stage character that best
represents you. Take intermissions as you see fit. Click on the stage if you have a hard
time seeing it. If you get bored, you can jump to the code. Most importantly, enjoy the
show!)
Act 1: Once Upon a Time…
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
1/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
2/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
3/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
4/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
5/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
6/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
7/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
8/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
9/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
10/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
Act 2: Crypto Basics
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
11/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
12/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
13/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
Act 3: Details
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
14/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
15/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
16/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
17/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
18/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
19/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
20/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
21/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
22/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
23/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
24/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
25/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
26/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
Act 4: Math!
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
27/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
28/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
29/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
30/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
31/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
32/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
33/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
34/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
35/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
36/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
37/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
Epilogue
I created a heavily-commented AES/Rijndael implementation to go along with this post and put
it on GitHub. In keeping with the Foot-Shooting Prevention Agreement, it shouldn’t be used for
production code, but it should be helpful in seeing exactly where all the numbers came from in
this play. Several resources were useful in creating this:
The Design of Rijndael is the book on the subject, written by the
Rijndael creators. It was helpful in understanding specifics, especially
the math (although some parts were beyond me). It’s also where I got
the math notation and graphical representation in the left and right
corners of the scenes describing the layers (SubBytes, ShiftRows,
MixColumns, and AddRoundKey).
The FIPS-197 specification formally defines AES and provides a good
overview.
The Puzzle Palace, especially chapter 9, was helpful while creating
Act 1. For more on how the NSA modified DES, see this.
More on Intel’s (and now AMD) inclusion of native AES instructions can be found here and
in detail here. - Other helpful resources include Wikipedia, Sam Trenholme’s AES math
series, and this animation.
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
38/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
Please leave a comment if you notice something that can be better explained.
Update #1: Several scenes were updated to fix some errors mentioned in the comments.
Update #2: By request, I’ve created a slide show presentation of this play in both PowerPoint
and PDF formats. I’ve licensed them under the Creative Commons Attribution License so that
you can use them as you see fit. If you’re teaching a class, consider giving extra credit to any
student giving a worthy interpretive dance rendition in accordance with the Foot-Shooting
Prevention Agreement.
251 Comments
1
Moserware
Recommend 43
Login
Sort by Best
⤤ Share
Join the discussion…
LOG IN WITH
OR SIGN UP WITH DISQUS ?
Name
Chandan Jha • 3 months ago
Wow! That was an awesome explanation. Thanks for the PPT and PDF... Good contribution...
Cheers!
PS: couldn't manage with the Maths part but still went through it. ;-) need to improve my
maths skills.
6△
▽ • Reply • Share ›
Anonymous • 8 years ago
Should be be in the preface of CS cryptography textbooks! Terrific
4△
▽ • Reply • Share ›
Adam M. Erickson • 4 years ago
This should be in CS and ISM textbooks. A+ Moser.
1△
▽ • Reply • Share ›
James McCune • 14 days ago
Awesome content man!
Really helped me out
△ ▽ • Reply • Share ›
Leonard Michael Hurlocker • 2 months ago
Love it! Thx.
△ ▽ • Reply • Share ›
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
39/45
1/20/2018
Reply
Share
A Stick Figure Guide to the Advanced Encryption Standard (AES)
Hope Ordu • 3 months ago
Lovely explanation. Couldn't have understood any better
△ ▽ • Reply • Share ›
Matthew Ewer • 5 months ago
In the big chart, bottom right, in the bottom right of the Inverse Mix table, I think that B
should be an E.
△ ▽ • Reply • Share ›
Lightning342 • 5 months ago
Great epilogue, I especially liked the math parts that visualize the operations. Just one issue;
in both encryption and decryption the last round is always the one with three steps (without
mixcolumns). Check the pseudo code in NIST.FIPS.197 (figure 5 & 12), or search the Internet
for images on "simplified aes decrypt" . So aes_act_3_scene_20_decrypting_1100 is
incorrect.
△ ▽ • Reply • Share ›
Sleem A. Lama • 6 months ago
This is awesome.. Thank you
△ ▽ • Reply • Share ›
ATA UR REHMAN • 10 months ago
Seriously One great article.. Loved it (Y)
△ ▽ • Reply • Share ›
Rami Stefanidis • a year ago
Very cool article. Thank you
△ ▽ • Reply • Share ›
Gidz Paul • a year ago
Awesome.. :o
△ ▽ • Reply • Share ›
Walter Zambotti • a year ago
Very nice. Did I miss where in the presentation you display the final encrypted text???
△ ▽ • Reply • Share ›
netdeamon • 2 years ago
Cool !!! Keep it up!
△ ▽ • Reply • Share ›
Felipe S Mattos • 2 years ago
this is rocksome! very nice work!
△ ▽ • Reply • Share ›
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
40/45
1/20/2018
△ ▽ • Reply • Share ›
A Stick Figure Guide to the Advanced Encryption Standard (AES)
assignment writing • 2 years ago
It's actually a good work that you have shared which covers up some topics about that kind
of subject that was being tackled in school for those students who studies in the field of
engineering. Through this, they can learn something that they will going to use as their guide.
△ ▽ • Reply • Share ›
Benjamin Barenblat • 3 years ago
A minor error in act 3, scene 11: entry a₀₁ of the right block should read ‘fb’, not ‘f8’. (This
has already been corrected in scenes 12 and 13.)
△ ▽ • Reply • Share ›
Kevin • 4 years ago
Thanks man!! :)
△ ▽ • Reply • Share ›
Raymond Starkey • 4 years ago
Talent, talent, talent, talent. Art - must try harder.
△ ▽ • Reply • Share ›
Theuns Alberts • 4 years ago
Brilliantly explained! And thanks for the effort with the accompanied code.
△ ▽ • Reply • Share ›
Todd • 4 years ago
Awesome. But where is the part where the NSA builds in a back door to circumvent all the
cryptology?
△ ▽ • Reply • Share ›
Anonymous • 4 years ago
was fun........gr8.......learning it and signng the letter....
△ ▽ • Reply • Share ›
Anonymous • 5 years ago
Can't figure out if ALL these have any relation at all with this one:
"The key to this encryption rule is given by two numbers n and r. The number n is chosen in
a very particular way: n is the product of two primes p and q. where n is the product of two
primes p and q. To encrypt x we just compute: y = x^r(mod n).
The decryption then works via a simple formula, analogous to the encryption: we compute
y^s(mod n).
Suppose we choose n = p * q = 29 * 37 = 1073. Let's take r = 25 with this choice of n and r,
the choice s = 121 is an appropriate decryption key...
The decryption illustrated on the previous page is possible because r and s have a very
special relationship. With p = 29, and q = 37, we compute:
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
41/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
special relationship. With p 29, and q 37, we compute:
m = (p-1) * (q-1) = 1008 and then we have chosen r and s so that:
r*s = 25 * 121 = 3025 = 1 (mod m)..."
Link: http://web.math.princeton.e...
△ ▽ • Reply • Share ›
otis root > Anonymous • a year ago
That is RSA
△ ▽ • Reply • Share ›
Cường Đặng Đình • 5 years ago
thanks very much!!!!!!!!!
△ ▽ • Reply • Share ›
Trung Le • 5 years ago
That was a really good work you have done! Helped me a ton to understand AES in a visual
way. Keep it up!
△ ▽ • Reply • Share ›
KF • 5 years ago
Thank you for your awesome job... really let me understand much. This is fun too. Appreciate
it very much.
△ ▽ • Reply • Share ›
Jeff Moser • 5 years ago
Thanks everyone for the kind feedback!
Anonymous: For details about being resistant to cryptanalysis, I recommend reading the
book but it's quite a bit more complicated than this comic. Perhaps try the Wikipedia page.
Regarding modes, Wikipedia's page on it is pretty good.
△ ▽ • Reply • Share ›
Charulatha Jain • 5 years ago
Its an awesome presentation and quite helpful for beginners to understand the concepts.
Thank you for the awesome presentation.
△ ▽ • Reply • Share ›
Anonymous • 5 years ago
This is one of the most superb explanations of AES I've ever seen. So easy to understand,
it's brilliant. But I'd love to know more about the resistance to cryptanalysis, I understand
what it is but I have no idea how AES resists it. Plus I'd like to know more about the various
"modes" you touched on!
In summary: encore!
△ ▽ • Reply • Share ›
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
42/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
durdave • 5 years ago
Great! But I'm still left with the question "Will Ashley go out with me?" Maybe if I get a
Ferrari?
△ ▽ • Reply • Share ›
Anonymous • 5 years ago
Superb. Keep it up Brother.
△ ▽ • Reply • Share ›
Anonymous • 5 years ago
Amazing would be an understatement!
△ ▽ • Reply • Share ›
naveregnide • 6 years ago
Hey! Just stopping by to say that this lovely comic really helped me understand AES a lot
more. Such a great sense of humour used in it too! Thanks!
△ ▽ • Reply • Share ›
Jeff Moser • 6 years ago
Thanks everyone for the kind feedback over the years.
Special thanks to txipxi for the Spanish translation.
Vincent: For details on how all S-Box values are calculated, follow along with the S-Box
demonstration section my example program and the f(x) and g(x) section as well. For even
more details, see how I implemented f and g. Note specifically how "f" is a multiply then an
add/xor. Each bit of the result of the multiply is obtained through 8 boolean multiplies/ands.
Hope that helps!
△ ▽ • Reply • Share ›
Vincent • 6 years ago
Hi Jeff, is it possible to show your working on f({18})={6a}? I have been trying to work out the
rotational matrix part but still getting the answer wrong. Did you sum up all the 8 rows of
multiplication before you XOR with {63}?
Is it possible can anyone show the working for multiple inverse for {58} is {18}?
△ ▽ • Reply • Share ›
Krishnaprasad • 6 years ago
This is great.. lot of effort to explain, very easy to understand!! awesome..
△ ▽ • Reply • Share ›
Anonymous • 6 years ago
W d f l! G t
k!
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
43/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
Wonderful! Great work!
Makes understanding AES a lot of fun!
Genius!
△ ▽ • Reply • Share ›
txipi • 6 years ago
Awesome!!!
My humble contribution to your great work, a Spanish translation:
http://www.slideshare.net/t...
△ ▽ • Reply • Share ›
The Grey Man • 6 years ago
WOW. Thanks for the excellent, amusing and visual run down on AES.
△ ▽ • Reply • Share ›
SherryL • 6 years ago
Wow, it's great to explain the AES this way. I've tried much to understand AES before I found
this. BRAVO! Thanks!
△ ▽ • Reply • Share ›
Anonymous • 6 years ago
I would like to read more like this..it was a fun way of learning for an adult.
△ ▽ • Reply • Share ›
Anonymous • 6 years ago
Thanks for this.
△ ▽ • Reply • Share ›
Jeff Moser • 6 years ago
20 box: It's a decent book if you want a very academic overview of AES. It was a bit too
academic for my tastes and was one of the reasons why I created this post.
If you're looking for a more hands-on/pragmatic understanding of AES, I'd recommend you
just read and understand the source code that I included with this post.
△ ▽ • Reply • Share ›
20 box • 6 years ago
Is that book you recommended is good? I am considering buying it here in India but it is too
costly a book for Indian standards and is not available on local markets.. so have to buy it
from amazon or something.. but too costly..
Just want to know if it is worth $100 or not? as it would be the price for me including
shipping...
△ ▽ • Reply • Share ›
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
44/45
1/20/2018
A Stick Figure Guide to the Advanced Encryption Standard (AES)
Sandoval • 7 years ago
wow!
99.9% of comp professionals never can talk in simple English; BUT you've just proved that
you are the 0.1%!
△ ▽ • Reply • Share ›
<Martani/> Fakhrou • 7 years ago
Totally awesome,
this is gonna help me in my crypto exam tomorrow :D
△ ▽ • Reply • Share ›
arun • 7 years ago
hey man..a very well explained..good job..
well m also working on AES and m really a bad prograamer..My work is with Equivalent
Inverse Cipher have you worked on it...got nay code of it????It's really urgent......pls
△ ▽ • Reply • Share ›
Viviana • 7 years ago
Thanks a LOT for this explanation!
I nearly had given up trying to understand AES when I found that..!
△ ▽ • Reply • Share ›
Anonymous • 7 years ago
After reading this I am not sure if I successfully crypt-ed or decrypt-ed my knowledge about
AES.
© 2015
http://www.moserware.com/2009/09/stick-figure-guide-to-advanced.html
45/45
Source Exif Data:
File Type : PDF File Type Extension : pdf MIME Type : application/pdf PDF Version : 1.4 Linearized : No Page Count : 45 Creator : Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36 Producer : Skia/PDF m63 Create Date : 2018:01:21 00:01:07+00:00 Modify Date : 2018:01:21 00:01:07+00:00EXIF Metadata provided by EXIF.tools