Which allows 25th word...2/3 seed-split or 2/3 Shamir?

[ramptomili777]

My AI research suggested that 25th word can be done with 2/3 seed-splitting but not with 2/3 Shamir. Please confirm?

I would be using Trezor Safe 3.

I cannot fully trust the person who would have access to 2 of the 3 metal seed storage pieces, so I need to include a 25th word just in case they try something-which may rule out Shamir's method.

[Charles-Tim]

It is the seed phrase that you can use to extended the 24 words seed phrase with addiction word called passphrase which is the 25th word, but I do not recommend seed splitting.

You can also learn about multisig wallet.

I cannot fully trust the person who would have access to 2 of the 3 metal seed storage pieces, so I need to include a 25th word just in case they try something-which may rule out Shamir's method.

If you can not fully trust them, why do you want to give them the seed phrase backup.

[coinlary]

There's  no need to split it if you will be adding a passphrase .

Just give them a qhole seed  phrase, use something that can't  be guessed as your pass phrase and give it to another person that has no connection  in annyway to the first person .

You don’t  neeed to explain what it's all about either, just give it to them to keep it safe . Before oing that make sure you have extra copies of the seed and passphrase that you keep your self  hidden in your house and other preferred  location.

 If you have trust issue, my afvice is just to handle them yourself.

[ABCbits]

My AI research suggested that 25th word can be done with 2/3 seed-splitting but not with 2/3 Shamir. Please confirm?

I would be using Trezor Safe 3.

Since you use Trezor Safe 3, consider using SLIP39 specifically. It's standard created by Trezor itself, but passphrase/25th word support is limited.

Can I use a passphrase with my SLIP39 wallet?

Yes, you can use a passphrase with a SLIP39 wallet. However, you should be aware that this is an advanced feature which adds even more complexity to your setup.

If you send funds to a passphrase-protected wallet, you must have the correct passphrase to access them.

If you forget or lose the passphrase, you will not be able to access your funds!

Make sure you properly understand how the passphrase feature works before using it. Funds secured by a passphrase cannot be recovered if you lose the passphrase!

[ramptomili777]

If someone has the 24-word seed, couldn't they brute force the 25th word paraphrase?

There's  no need to split it if you will be adding a passphrase .

Just give them a qhole seed  phrase, use something that can't  be guessed as your pass phrase and give it to another person that has no connection  in annyway to the first person .

You don’t  neeed to explain what it's all about either, just give it to them to keep it safe . Before oing that make sure you have extra copies of the seed and passphrase that you keep your self  hidden in your house and other preferred  location.

 If you have trust issue, my afvice is just to handle them yourself.

[Charles-Tim]

If someone has the 24-word seed, couldn't they brute force the 25th word paraphrase?

It depends on how long the passphrase is. Characters that is 8 in length, having upper case and lower case alphabet, number and 1 other character will be hard to brute force. Some people can make it more longer as they backup the passphrase in different locations away from the seed phrase backup. More characters, harder and becoming impossible to brute force.

[coinlary]

If someone has the 24-word seed, couldn't they brute force the 25th word paraphrase?

~snip~

As it's been answered, it depends on what you use as your passphrase and how long it is.

Passphrase have one usefulness and it’s to give extra protection to your exposed seed, giving the seed out willingly doesn’t mean the person on the  other end knew you used a passphrase. Set an alert to know when  they become untrustworthy by  keeping a small change inside the wallet that they can withdraw so you can take immediate action regarding  your wallet(the one with passphrase) .

That’s why i said if you have trust issue then just handle it yourself instead of giving it to a third party. On the other hand, i believe you're  not planning  to give it to someone that will spend the remaining  of their lives trying to brute-force a passkey .

[hosemary]

You want to create a 2 of 3 slip39 seed and give someone access to twp out of the three shares? Am I getting you correctly?
If so, you are going to give that person full control over your funds. Why don't you go for a 3 of 3 slip39 seed, instead?