-snip-
My questions here are following :
Is it possible to "sign" the transaction to my specific bitcoin adress offline already so it will be executed immediately when i am online again ?
Edit : yes , just did it.
Just wondering what is the difference between loading this signed transaction file in ethereum and typing in my private key ? Isnt it exactly the same when it comes to security ?
I still see no point how it can be hacked, because the transaction you broadcasted will always be faster than the one someone could do after a keylog hack ?
The confirmation matters more. Theoretically, if the pool allows RBF, the pool will accept the transaction with the more fee and thus one of the transaction would likely lose. It would be even easier if the hacker owns a pool with a high amount of hashrate.
If it is important to to this offline, is it also ok to just do this on another computer which is offline just during the period of this transaction and afterwards online again?
Because i read that for private keys one should use a seperate offline box which is never connected to the internet. But after the transaction is done, it doesn't matter anymore, does it ?
Should be safe if you do not reuse the address. Once your private key is exposed to a computer that has ever or will ever connect to the internet, it would be unsafe.
The always offline box is just important for generating cold storage files ?
I would recommend using a dedicated offline computer just for address signing. If it has been online before, a malware can make the RNG weak and thus generate weaker addresses[Not that I know of any]. If it goes online in the future, the virus can potentially broadcast all the recorded private keys to the server.
Does it make sense at all using an offline computer ?
Yup. An offline computer doesn't cost much, a raspberry pi would be more than sufficient to serve its purpose.
I mean just sweeping a private key into electrum should be fine ? even if the computer is unsafe the guy who probably keylogs will always be behind this transaction and has no change to be faster, does he ?
He can always run a script.
Edit :I tried to do it like here :
https://m.reddit.com/r/btc/wiki/electrumBut i am not able to do step 3. Save out the Master Public Key from Electrum. I am not able to click the button.
Then i tried to do it a different way with just the public key, why do i even need the Master Public Key ?
The master public key is for Hierarchical Deterministic (HD) Wallet. Unless you select that, you cannot click on MPK. HD wallets provides more privacy and ease of use for its user.
