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Are timelocks a bad idea when it comes to wrench attack protection?

I sometimes read here and on other websites that one way to prevent a violent attacker from stealing all your coins are wallets with some kind of timelock, e.g.:

Blockstream Green’s 2FA: The setup here is a timelocked 2-key multisig, one key is held by you and the other one by Blockstream. If you send coins to this kind of wallet, for one year the wallet behaves like a 2-of-2 multisig. You have a 2FA code to ask Blockstream to co-sign. After one year, the wallet’s behavior changes and the coins become spendable with your key alone (not with Blockstream’s key.).
The idea now is to keep your key at home and the 2FA code at a bank vault. The bank can’t steal anything from you and after one year you can send send the coins out on your own, even if the bank/someone else stole the contents of your box.
Moreover, a violent attacker with access to your key cannot spend your coins immediately, but has to wait one year. Within that year, you can simply go to the bank, get the 2FA code and transfer the coins to a new wallet.

Collaborative Multisig like Casa (or Unchained or Nunchuck): You have a 2/3 multisig with one key at home, one at a bank vault and one key is held by Casa. If you ask Casa to co-sign, they will do so with a delay of one week.
If an attacker comes to your home and wants you to send him your coins, you either have to somehow get to the bank vault, which is a big problem for the attacker, or he forces you to ask Casa to co-sign. From the moment you asked Casa, they take one week to do so. So, once the attack is over, you have one week time to ask Casa to not co-sign because you were under attack.

Now, what came to my mind eventually, is that those kind of schemes basically set a bounty on your head. In scheme one, the attacker is motivated to kill you, because then you will not go to the bank and get the 2FA code. Thus, by killing you, after one year he can get the coins. In scheme two, the attacker is motivated to kill you, or at least hospitalize you for some weeks such that you can’t contact Casa and ask them to stop the process.

TLDR: Timelocked wallet solutions may not protect you from wrench attacks, but actually may make things worse by motivating the attacker to kill/badly harm you.



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2 Comments

  1. >Timelocked wallet solutions may not protect you from wrench attacks, but actually may make things worse by motivating the attacker to kill/badly harm you.

    Correct. Having the need to travel a distance to get a couple of signatures, might safe your fingers from being cut.

    OPSEC is still the way to prevent such attacks.

  2. Interesting argument, thanks for sharing. One nitpick:

    > In scheme two, the attacker is motivated to kill you, or at least hospitalize you for some weeks such that you can’t contact Casa and ask them to stop the process.

    You could contact Casa from the hospital. The attacker would have to imprison you.

Is it me or the mempool is clogged?

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