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I found an old paper wallet on an old computer of mine which is offline (I can count the number of coins with my fingers). I would like to distribute these coins now among 6-9 wallets (I want to give some family members coins) and have a few questions. Partially they are also out of curiousity, since I am learning more about bitcoin now that I have discovered the coins again.

1.) Is it safe if I create a raw transaction on the offline computer so I can execute it on my online computer?

2.) I read that making a transaction will reveal the public address of the current address. I also read that the signature of multiple transactions can help hackers to figure out my private key. It is therefore recommended to empty the old address when I move stuff around. Nevertheless, I am curious about the following:

However, wouldn't you say that the old address is still relatively secure after doing a single transaction? Meaning, while I should empty the old address at some point, a brute force attack would most likely not be able to hack the public key within a month of the transaction.

3.) If I send the bitcoins to multiple addresses in one multi-recipient transaction, will this raw transaction have a signature for each receiver? Or will I only sign with one signature (effectively the same as if I just moved money to one address)? Meaning, does an address become more exposed after a single multi-recipient transaction vs. a single one-recipient transaction?

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1.) Is it safe if I create a raw transaction on the offline computer so I can execute it on my online computer?

Yes, this method, called using cold wallets is very effective at keeping coins safe.

  1. An address either never spends (the public key is not revealed) or it spends (the public key is revealed). Spending fewer times from an address won't make it less secure (unless you use very old or home-made signing code). And the security difference between non-spending and spending wallet is negligible. (Otherwise, there would be a price crash and chaos)
  1. Every input has its own signature, not every output. So, by making all those payments at once, you'll save lots of $ in transaction fees.
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  • Thank you for your response! Could you please clarify what you mean with "very old or home-made signing code"? I was going to create the raw transaction with the brainwalletgenerator.com code from github.com/BrainwalletGenerator/BrainwalletGenerator – bitcoinquestion2021 Feb 17 at 16:30
  • I can't comment on that site, I use coinb.in instead but if you find it trustworthy you can use it. The problem is, signing requires a random and secret constant k which has to be different every time a different message is signed; otherwise, the private key can be extracted from public signatures. Any new services or websites today handle this correctly there are very few software suffering from this bug. However it really annoys me that this website claims to be open-source without publishing their code – MCCCS Feb 17 at 16:40
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    No modern code uses a RNG for signing and haven’t done so for years. The only time entropy is important is key generation. – Anonymous Feb 17 at 16:59

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