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Show HN: SHA-256 Animation

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Re: Show HN: SHA-256 Animation

#51

Post by kebman »

folli wrote: post #46
jonplackett wrote: post #22

I once heard about a meeting where someone did a presentation for the best part of an hour to a room full of Japanese people. They all nodded along, smiling as the presentation progressed. It wasn’t until the end that the presenter asked them what they thought. They all just kept smiling, but no answer. Someone at the front turned and talked to the room (in Japanese) then turned to the presented and said “they do not…

You need to watch his video, very cool, it really helps to understand how this works: https://www.youtube.com/watch?v=f9EbD6iY9zI

That video is really, really awesome! And it won't leave you feeling "Japanese" either. (Which is a great people, btw. I'd really like to go there someday, mostly for the food and language and history. And Anime also, I'm forced to admit.)

Re: Show HN: SHA-256 Animation

#52

Post by mystickphoenix »

Zhyl wrote: post #23
inersha wrote: post #2

I wanted to understand how SHA-256 works, so I made a terminal animation that shows the bitwise operations at each step. I wrote a text guide in the README.md to explain what's going on. I think my technical terminology is okay. I'm new to hash functions though, so I don't yet know why SHA-256 has been designed in the way it has (e.g. why exact numbers were chosen in the bitwise rotations). As far as I understand, th…

1) I loved this video. 2) I did have to take a sip of tea and think about my life when I realised I was watching a video by a Welshman about mining. 3) Although having said this, 'Welsh Bitcoin Miner' is going to fit seamlessly into my West Country themed cyberpunk adventure 'Cider Punk'.

You could call it CIDR Punk if you want to be a bit more on-the-nose ;)

Re: Show HN: SHA-256 Animation

#53

Post by chias »

folli wrote: post #46
jonplackett wrote: post #22

I once heard about a meeting where someone did a presentation for the best part of an hour to a room full of Japanese people. They all nodded along, smiling as the presentation progressed. It wasn’t until the end that the presenter asked them what they thought. They all just kept smiling, but no answer. Someone at the front turned and talked to the room (in Japanese) then turned to the presented and said “they do not…

You need to watch his video, very cool, it really helps to understand how this works: https://www.youtube.com/watch?v=f9EbD6iY9zI

There's a few things in there that are factually incorrect -- in particular, the false notion that "every input has a unique output" can be quite dangerous in some cryptographic settings.

That said, the purpose of this talk is about the mechanics of the function, and not its properties or how to use it safely. So don't let that detract from what is, really, an awesome presentation.

Re: Show HN: SHA-256 Animation

#56

Post by imoverclocked »

inersha wrote: post #2

I wanted to understand how SHA-256 works, so I made a terminal animation that shows the bitwise operations at each step. I wrote a text guide in the README.md to explain what's going on. I think my technical terminology is okay. I'm new to hash functions though, so I don't yet know why SHA-256 has been designed in the way it has (e.g. why exact numbers were chosen in the bitwise rotations). As far as I understand, th…

Congratulations on the worlds slowest and useful SHA-256 implementation! :)

Re: Show HN: SHA-256 Animation

#57

Post by nayuki »

imoverclocked wrote: post #56
inersha wrote: post #2

I wanted to understand how SHA-256 works, so I made a terminal animation that shows the bitwise operations at each step. I wrote a text guide in the README.md to explain what's going on. I think my technical terminology is okay. I'm new to hash functions though, so I don't yet know why SHA-256 has been designed in the way it has (e.g. why exact numbers were chosen in the bitwise rotations). As far as I understand, th…

Congratulations on the worlds slowest and useful SHA-256 implementation! :)

There is a far slower implementation: http://www.righto.com/2014/09/mining-bitcoin-with-pencil-and...

Re: Show HN: SHA-256 Animation

#58

Post by nayuki »

jagged-chisel wrote: post #8

I would love to build something like this for encryption algorithms that twiddle bits (DES and friends.) Even for the math-based algorithms, but I have a had time imagining how to make those interesting.

I have Excel spreadsheets showing every bit of the calculation of AES and DES: https://www.nayuki.io/page/aes-cipher-internals-in-excel ; https://www.nayuki.io/page/des-cipher-internals-in-excel

Also, some people have been sharing a video explanation of AES/Rijndael. It is actually rendered from someone's Shockwave Flash movie. https://web.archive.org/web/20051124061027/http://www.cs.bc....

Re: Show HN: SHA-256 Animation

#60

Post by tridentboy »

chias wrote: post #53
folli wrote: post #46

Earlier quoted context omitted.

You need to watch his video, very cool, it really helps to understand how this works: https://www.youtube.com/watch?v=f9EbD6iY9zI

There's a few things in there that are factually incorrect -- in particular, the false notion that "every input has a unique output" can be quite dangerous in some cryptographic settings. That said, the purpose of this talk is about the mechanics of the function, and not its properties or how to use it safely. So don't let that detract from what is, really, an awesome presentation.

I'm sorry, could you please elaborate? I was always under the assumption that hash functions have to be deterministic, and thus, that "every input has a unique output" was a correct statement.

AFAIK the contrary is invalid, so that "not every output is the result of one and only one input".

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