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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?

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what for would one need that? –  gnat Jul 18 '12 at 23:17
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4 Answers

up vote 4 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

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thank you! what a lifesaver that PDF was. –  jcomeau_ictx May 23 '13 at 7:26
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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.

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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
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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!

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That is the plan, now that i know that this dosen't exist yet :D –  Xenland Jul 24 '12 at 17:56
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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.

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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
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