OK so I am trying understand the mechanics of a bitcoin transaction and am confused.
Please see screen shot of transaction on blockchain.info here:
https://i.imgur.com/Dvlw012.jpgWelcome.
A blockchain explorer does not know which are your addresses and which not so it may confuse you.
I sent BTCs from my bitcoin core wallet to a paper wallet (with some BTCs left behind).
What I am confused about is where the remaining BTCs left in original wallet have gone.
To a change address.
In the screenshot you can see this transaction was split between my paper wallet public address and some other address which I did not enter and have no idea where it came from.
What is this address? How is it generated? What does it mean? Who's is it?
Change.
Same as every other address.
It means that everything is working as it should be.
Yours.
I am pretty sure these are still my coins given that my local bitcoin core client lists the appropriate balance.
However, I had entered my bitcoin core public address as a watch-only receiving address on blockchain.info and now that balance reads 0.00 BTC (whereas I had expected the remaining BTCs would still be listed there).
Much thanks for any help understanding how this works.
Firstly to help you see the address in core, enable coin control.
Settings -> Options -> Wallet -> check Enable Coin Control features -> confirm with OK
It might have to restart for that, Im not sure.
Once you have it enabled go to
Send -> Inputs -> select Tree mode and search for the address you know (13yv...). There is a little triangle on the left side, click it to expand the line. It will show the address 14C9... with a label (change).
Like this:
Now, what is change? In Bitcoin you have no balance even though the wallet shows it to you like that. Its just a simplification for you, the network works with transactions only. Think about it like this. You received a 0.033 BTC blob in the past (see Total inputs on blockchain.info) and now you want to use it to send 0.02 to your paperwallet. Bitcoin core has to use the entire blob and reusing address is considered not so good, so it sends the rest (minus the fee you pay) to a newly generated address, the change address. Bitcoin core has up to 100 address pre generated and hidden from you for this and other purposes. You should still make regular backups as these 100 addresses are used after some time which might make an backup too old useless.
