Tell me more ×
Programmers Stack Exchange is a question and answer site for professional programmers interested in conceptual questions about software development. It's 100% free, no registration required.
up vote 6 down vote favorite
1

Is there any possible way I can download a program, type in a message, and watch the program display visually what iterations are going on and what formula the character is being fed through all the way down to the output message of a SHA-256 operation or is that just too geeky to ask for?

share|improve this question
2  
what for would one need that? – gnat Jul 18 '12 at 23:17

4 Answers

up vote 2 down vote accepted

Note that in the graphic you've linked in the comment:

http://upload.wikimedia.org/wikipedia/commons/thumb/7/7d/SHA-2.svg/400px-SHA-2.svg.png

each A to H is a 32 bit value, and the dark blue boxes are binary operations:

Ch(x,y,z) = (x and y) xor (not(x) and z)

You won't see anything useful on this level, and when drawing a complete diagram with bits, you won't see anything useful in an ocean of moving bits, as funny as it would be.

Here are some example values with intermediate internal states, already giving an ocean of hex digits, but are useful to verify your own implementations.

http://csrc.nist.gov/groups/ST/toolkit/examples.html

http://csrc.nist.gov/groups/ST/toolkit/documents/Examples/SHA256.pdf

share|improve this answer
thank you! what a lifesaver that PDF was. – jcomeau_ictx May 23 at 7:26
up vote 3 down vote

Look at this online - SHA-256 Encryption Tool. You may look at algorithm how it works, but debugging the process does not seem feasible.

More info on subject matter in Cryptographic hash function and post here.

share|improve this answer
I have examined those before, I'm mostly interested in an animation version of this image: upload.wikimedia.org/wikipedia/commons/thumb/7/7d/SHA-2.svg/… Found at the page of: en.wikipedia.org/wiki/Sha256 I'd just like to see it in action obviously debugging is impossible because then that would make the hashing function flawed. – Xenland Jul 18 '12 at 23:40
up vote 2 down vote

You should be able to build this.

  1. As mentioned, get some source code for SHA-256 encryption.
  2. Trace the algorithm for the events you want to plot graphically.
  3. Create listeners for those events--have them pick up the values being operated on.
  4. Send messages to your graphics/visual tool/classes from the listeners.
  5. Run the encryption on something and see what happens.

Good luck!

share|improve this answer
That is the plan, now that i know that this dosen't exist yet :D – Xenland Jul 24 '12 at 17:56
up vote -3 down vote

The real answer in this case would be: it's not even possible to have an implementation for reference, how you can pick just 1 program to debug your SHA 256 ?

The NSA published the algorithm for the SHA not a source code for a specific implementation. You can't do what you want to do, you just can study the algorithm.

share|improve this answer
6  
We are programmers. Resistance is futile. Your algorithm descriptions will be assimilated. We transform them to running implementations in any language imaginable. – Secure Jul 19 '12 at 6:06

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.