Ia blockchain still prevalent in 2023?
How do I store data using it?

shove that data right up your ass.

Nobody cares about blockchain anymore, the hype train is now with statistics on steroids aka "AI".

You can store blockchain data using e.g. an SSD, or even better, using /dev/null .

B-trees are more prevalent, and they're more flexible too, so if you don't understand how blockchains work they're a better choice. They come in popular and battle-tested libraries such as sqlite, or in a dedicated server solution such as postgres and mariadb

Yes, it still exists and is fairly useful for some very specific applications.
However, storing significant amounts of data is not one of those - it is simply too slow and unwieldy for that. If you want to store actual data, check @lorentz 's answer.

You can use Blockchain as a "notary" to authenticate small data payloads. Ex: We use it for shipping manifests. You get the SHA256 of the entire manifest, sign it with your private key, and store those fewer-than-64Kb using AWS' blockchain-AAS.
If further down the line someone accuses you (and some other government) of falsifying the shipping manifest, you show them the Blockchain and have them check it.
Either you tampered with the manifest (signed hash doesn't match), or it is legit (everything matches) or you and Jeff Bezos are in a shadowy cabal formed to prevent that specific guy from getting his Funko Pops or whatever (Blockchain rewrite).
It is very, very slow, but effective for this application.

no, and you don't.

@JsonBoa If you just want to have a reputable third party bear witness to the authenticity of your hash, a blockchain sounds like overkill. They could just cryptographically sign the time-stamped data.

Blockchains are inefficient and inflexible, in the sense that carving your data in slabs of granite is inefficient and inflexible, except granite carving scales linearly and a real blockchain doesn't. A comparably expensive granite-carving operation could probably have far better throughput than bitcoin.

@lorentz we tried that approach, too. But most "reputable third parties" are not very welcome in many parts of the world (unreputable parts, those places are. But with deep ports and lots of cheap stuff).
Surprisingly, AWS is welcome. Don't know why, don't care either.

@JsonBoa You can have a second company sign your data and it'll only be linearly more expensive with no coordination required. If you use a real blockchain independent nodes have to reach a majority of the others and use some complicated and thoroughly unnecessary byzantine consensus algorithm.

Blockchains only make sense when you can't get away with anything less than a byzantine state machine. If all event sources can coordinate because there actually exists a sjngle company that owns the system, individually signed contracts are vastly more efficient.

The whole point of Blockchain is when you do not want to trust an established, central party, to agree on the validity of something.

That's why banks can't control cryptocurrency, but of course, that poses several big drawbacks.

Individually signed contracts tend to be more than enough for most use cases.

Blockchain is less about storing data and more about validating and storing data

@jestdotty

I'm not trying to go into the shenanigans all these things (Blockchain, govts, fiat) can be used for.

I merely described the technological use case for Blockchain.

Of course, it can be abused like every other system ever.