[REDACTED]

[SeeBiscuit]

[odolvlobo]

Search engine results read to me that it's basically something that the miners rely on. It's part of the protocol that can broadcast a message to all concerned, in a way that the miner know 100% it's from an "authorized" source.

Is that it's only function?

Would catastrophe ensue if an evil person got ahold of the bitcoin alert key or a copy of it?

I still don't quite grasp what it is, however.

Like, is it a thing? A button? A script? Part of the software itself?

Does it have a private key? Can someone hold it in their hand or does it only exist in a state of information?

Thank you <3

The alert key was a private key that allowed its owner to send a message to every node on the network. It was disabled years ago.

[Upgrade00]

Is that it's only function?

Yes. It's major function was to alert all concerned of any critical situation on a particular version of the network, same way people are sent warning triggers when a natural disasters is expected to hit.

Would catastrophe ensue if an evil person got ahold of the bitcoin alert key or a copy of it?

That was possible. It was also becoming difficult to manage due to emergence of different types of wallets.

I still don't quite grasp what it is, however.
Like, is it a thing? A button? A script? Part of the software itself?
Does it have a private key? Can someone hold it in their hand or does it only exist in a state of information?

It's a private key which was given to Bitcoin core developers at the time - https://en.bitcoin.it/wiki/Alert_system
This is another reason it was stopped, cause they could give it, but not take it away. Past developers who were no longer actively working on the network still had access to it and could send a alert message at anytime without anyone knowing who exactly sent it.

[pooya87]

It was not a Bitcoin thing but a "bitcoin core" thing and it had nothing to do with miners.
Just like what Electrum has an option to let the users of the client know that there is a new version available, the users of bitcoin core client had that option to be alerted by the developers of that client if there were any critical bug in the version they were running and if they needed to take any actions such as upgrading to the newest version that fixed it.

It's a shame it got removed instead of being improved.

[hd49728]

The alert key was a private key that allowed its owner to send a message to every node on the network. It was disabled years ago.

It was disabled after compromise and some more information about its vulnerabilities and progress of development to disable it.

Satoshi's sendalert.cpp
Alert Keys and Alert System Vulnerabilities Disclosure