375K views · May 12, 2020 · 22:59 · 3 HN recommenders · 4 mentions · discussed 2020–2022
A step-by-step animated explanation of how SHA-256 works, from padding and message schedule to the compression function and final hash, with source code for the animations.
Why Hacker News points people here: Commenters call it clear enough to implement the algorithm from, and teachers use it in courses.
“I found this video to be an excellent explanation and sufficient to implement the algorithm”HN comment, 2022
“I found this video to be an excellent explanation and sufficient to implement the algorithm”
Excellent explanation, enough to implement the algorithm
I found this video to be an excellent explanation and sufficient to implement the algorithm: this video Code: link This site contains a nice visualization: link
“Here's the author doing an in-depth explanation of how SHA-256 works using this code”
In-depth author explanation of how SHA-256 works
Here's the author doing an in-depth explanation of how SHA-256 works using this code: this video I'm halfway through, but looks very well done, thanks!
“When we taught SHA-256 last semester, we linked to this YouTube video”
Used in teaching SHA-256 to a class
Oh this is great. When we taught SHA-256 last semester, we linked to this YouTube video: this video . Next time we do it, we'll probably link to both. Having several different ways to visualize the same thing is very helpful, and I like that this one moves quickly. A couple of details missing from this visualization are how you pad a message to be a multiple of the block size, and how you chain blocks together to form a longer message. In the pseudocode at link , that's the "Pre-processing (Padding)" part and the "for each chunk" loop just below it. I get why you'd want to leave those things out, since they're not really the interesting part, and the screen is already pretty packed as it is. If anyone's feeling curious about implementing this yourself, take a look at these project notes: link . At some point I'll clean that up for public consumption, but for now just ignore the parts about grades and cheating :)
“Seems like the author created a video for this”
Author's video version of the SHA-256 animation
This looks great, though it requires quite sometime to go through it (and figure out what could possibly be understood by someone with knowledge of programming and bit wise operators, and what can just be skipped because it’s something only cryptographers can understand). If someone were to make a slower video explaining it with all the sections from this dissection, that’d be even more awesome. Edit: Seems like the author created a video for this — this video (thanks to 1_player’s comment at link ) On a tangent, here’s an animation (by someone else) explaining AES encryption — link (thanks to harrigan’s comment at link )
