Semicolony ELI5 · comic

Hash functions.

A blender that turns anything into a fixed-size fingerprint.

In it goes.

1
Feed in anything at all — a single letter, a whole book, a 4 GB video.
2
The hash function is the blender: it mixes and scrambles every byte.
3
Out comes a short fingerprint, always the same length whatever you put in.
One typo, brand-new print.

4
Same input, same fingerprint. Change one letter and it’s utterly different.
5
It only runs forwards — there’s no un-blend button, which is why passwords are stored this way.
Shelf 7. No searching.

6
Use the fingerprint as an address and you jump straight to a value — instant lookups.

Drop anything into the blender and the same short fingerprint always comes out — but you can’t un-blend it.

Semicolony semicolony.dev/eli5/hash-function/comic