-snip-
Thanks for the above. So ultimately unhardened vs hardened doesn't matter a great deal in multisig?
Yes, safer than SingleSig.
The difficulty on getting the necessary number of xprv keys is harder,
but it still depends on how the cosigners handle their individual private keys.
For example:
Since each cosigner wallets contain (
e.g. 2-of-3) all three xpubs, if one cosigner wallet is compromised, the attacker will need to get one private keys from one of the other two cosigners.
Still good since it's still safe as long as the other two cosigners are secured.
In case that the attacker is one of the cosigner, all he need to do is "
ask" for a single private key from either cosigner to get full control of their funds.
By saying "
ask", I mean mislead the cosigners into giving him a private key like of a used address which seem harmless if the person doesn't know the risk.