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Bitcoin => Bitcoin Technical Support => Topic started by: kbdwarrior on April 01, 2024, 12:14:12 PM



Title: Question about degrading the n in a m/n Multisig setup
Post by: kbdwarrior on April 01, 2024, 12:14:12 PM
If I have a m/n Multisig setup, with n much larger than m, does losing/destroying one of the n seeds degrade my setup to a m/(n-1), just as long as n-x > m and I have all the relevant meta information like all xpubs, derivation path, etc.?
Example: Create a 2/10 Multisig. Destroy one of the 10 seeds. Do I now have the equivalent of a 2/9 Multisig?


Title: Re: Question about degrading the n in a m/n Multisig setup
Post by: Charles-Tim on April 01, 2024, 12:19:19 PM
Example: Create a 2/10 Multisig. Destroy one of the 10 seeds. Do I now have the equivalent of a 2/9 Multisig?
If it is 2-of-10 multisig. 2 keys are needs to sign before you can be able to broadcast transaction, while the remaining are needed to setup your wallet. It can not become 2-of-9. You need all the 10 keys for wallet recovery.


Title: Re: Question about degrading the n in a m/n Multisig setup
Post by: LoyceV on April 01, 2024, 12:19:40 PM
Create a 2/10 Multisig. Destroy one of the 10 seeds. Do I now have the equivalent of a 2/9 Multisig?
As far as I know, 2-of-10 gives a larger transaction size than 2-of-9.


Title: Re: Question about degrading the n in a m/n Multisig setup
Post by: kbdwarrior on April 01, 2024, 12:36:49 PM
Create a 2/10 Multisig. Destroy one of the 10 seeds. Do I now have the equivalent of a 2/9 Multisig?
As far as I know, 2-of-10 gives a larger transaction size than 2-of-9.
Good point, thanks.


Title: Re: Question about degrading the n in a m/n Multisig setup
Post by: Findingnemo on April 01, 2024, 12:48:25 PM
Example: Create a 2/10 Multisig. Destroy one of the 10 seeds. Do I now have the equivalent of a 2/9 Multisig?
If it is 2-of-10 multisig. 2 keys are needs to sign before you can be able to broadcast transaction, while the remaining are needed to setup your wallet. It can not become 2-of-9. You need all the 10 keys for wallet recovery.

As long as metadata is available then there is no problem with the wallet recovery even if one of the seed phrases is lost. to OP, technically it reduces the security of the wallet and considering 2 out of 10 then losing 1, the security concern for the remaining available cosigners is negligible.


Title: Re: Question about degrading the n in a m/n Multisig setup
Post by: kbdwarrior on April 01, 2024, 12:53:02 PM
Example: Create a 2/10 Multisig. Destroy one of the 10 seeds. Do I now have the equivalent of a 2/9 Multisig?
If it is 2-of-10 multisig. 2 keys are needs to sign before you can be able to broadcast transaction, while the remaining are needed to setup your wallet. It can not become 2-of-9. You need all the 10 keys for wallet recovery.

[...] technically it reduces the security of the wallet and considering 2 out of 10 then losing 1, the security concern for the remaining available cosigners is negligible.
Could you please elaborate how losing a seed as long as the quorum is available reduces the security of the wallet?


Title: Re: Question about degrading the n in a m/n Multisig setup
Post by: Zaguru12 on April 01, 2024, 12:59:11 PM
If you have the Xpub of the 10 co-signer then you can use it to recover the other co-signers without having the need for the 10th seed phrase since you wouldn't be needing it for signing of the transaction. you can simply just create another multi sig again and move the funds there because losing of the sedd could have reduce the security of the wallet.


Could you please elaborate how losing a seed as long as the quorum is available reduces the security of the wallet?

if someone gets hold of one of the co-signer details then with the ratio of n:m used, they might be needing just one more co-signers details. except if the xpub and derivation path isn't on the lost back up


Title: Re: Question about degrading the n in a m/n Multisig setup
Post by: nc50lc on April 01, 2024, 02:21:05 PM
Example: Create a 2/10 Multisig. Destroy one of the 10 seeds. Do I now have the equivalent of a 2/9 Multisig?
Technically, each of your 2-of-10 MultiSig address is a script consisting of 10 public keys and the number of signatures required to unlock it,
When hashed, it produces a specific scriptPubkey (shown as address in wallets)
Even if you lose the seed of one of the public key, your wallet will still have to include that public key when it needs to unlock that script.

Because otherwise, a script with 9 public keys, even though consisting of same public keys and same number of required signatures
will be an entirely different script and will produce a different scriptPubkey.

So it's still a 2-of-10 in your wallet and in the Bitcoin blockchain.