How did localbitcoins implement the work with bitcoins on their server?

Question

bitcoin

Interested in the principle itself.
Have they installed the console version of the bitcoin program and interact with it through a node, or how is it done with them?
Simply put, how to make a local wallet with a bunch of wallets inside?
It seems like when downloading a bitcoin wallet, the wallet turns out to be only 1, or am I confusing something?
How is the exchange done?

Answer 1

There are no wallets. There are ecdsa keys. One private key gives 2 addresses (because there are 2 ways to represent a public key - normal and compressed). The private key is just a bigger number. If you're lucky (not) you can accidentally guess someone else's key and become a crypto millionaire.
These are the very first and simplest types of addresses.
Then scripts appeared - a stack machine, the code for which is stored in transactions. The hash from the script also gives the address.
What is called a wallet in bitcoin is just a container with keys.
By default, bitcoin-core generates 100 keys when creating a wallet.
You can also generate them yourself to opupenie.