Use It Once: why reusing a bitcoin address is dangerous

[Nathrixxx]

Either wallet or changing your wallet address should pose no risk to us, as long as we understand how we could prevent exposing ourselves to any security threats when using a wallet. The problem is not with the address we are using, but with exposing it and not being able to maintain high security measures, which is at risk because many don't know about safety information and what not to do.

[windpath]

Thanks all, lots of good points. Taking them in order:

Technically not reusing address may only slightly decrease the risk of losing funds in this case. It will NOT remove the risk if the RNG is broken

Agreed, and nc50lc put it well too. A broken RNG or a non-deterministic nonce is the real bug, and RFC 6979 (and BIP-340 for Schnorr) is what made that class rare. The chapter's narrower point is that reuse is what turns one bad signature into "everything at that address," instead of one payment.

If you use Bitcoin to receive payment, you certainly can't be changing your address every time you make a transaction with it.

You can, and most setups already do: any HD wallet hands out a fresh address per request, and a merchant server like BTCPay makes one per invoice. For the cases that really need one public identifier (donations, a signature in a profile), silent payments or an xpub on your own server give payers a fixed thing to pay while every payment still lands on a new address.

when it comes to participants in signature campaigns, making continuous request for change of wallet address might be a burden to the campaign manager

Fair, and nobody needs to pester a manager every week. Treat the campaign address as an inbox: let payments land, then move them to your own wallet in one transaction (coins from that address only), and never keep savings there.

Could the section on already reused addresses also cover an address that is still published on a website or saved by regular payers?

Good suggestion. Short version: replace the published address with something that hands out fresh addresses (silent payments code, BTCPay, or a Lightning address for small amounts), then keep watching the old one for a while, since saved addresses keep getting paid. Peter Todd's warning about static addresses with no expiry is in the chapter for exactly this reason.

Abandon their wallets could use some clarification here.

That phrase isn't in the chapter. The advice is the narrow one: stop using the reused address, and if it still holds coins, move them in one transaction to a fresh address in the same wallet. No need to migrate to a new wallet unless your seed itself is in doubt.

this conventional address poison pattern

Good addition. A visible, long-lived address is also what makes look-alike "poisoning" addresses worth creating. One more reason to copy addresses fresh from your own wallet every time.

[Kalchef]

This is something that I don't even bother to practice, I have read alot about it many times but I don't just care because my private key is my top priority, if kept very well offline there is nothing to worry about.

I also don't use a recovery seed more than two years and I am dumping it, even if it's on a hardware wallet I will wipe the old one and create a new one, maybe this method is not that bad? Or it makes no difference?

[Catenaccio]

Either wallet or changing your wallet address should pose no risk to us, as long as we understand how we could prevent exposing ourselves to any security threats when using a wallet. The problem is not with the address we are using, but with exposing it and not being able to maintain high security measures, which is at risk because many don't know about safety information and what not to do.

When you use wallets and addresses, you will possibly leak your privacy, not only security of wallets and fund. For your wallet security, firstly it must be from security of your devices. Because if you use an infected device for creating your wallet, there is high possibility that your wallet will be known by hackers. When hackers take action to steal your coins will depend only on them, you can not control their action or avoid it.

If the device is clean and secure, you will have to do next steps with your wallet, how to download it, verify it, install it, then create and use your wallet. In practice, how you use address, change address, use coin control, choose UTXO for your transactions together with your practice online and offline elsewhere will contribute to your Bitcoin privacy and privacy in general.

[Brian Jeri]

Address reuse is one of those habits that seems harmless until you look at what it leaks. Privacy alone is a good enough reason to avoid it, even before getting into key exposure or future cryptographic risks.

Modern wallets already generate fresh addresses automatically, so there’s really not much upside to reusing one anymore.