Are there people using Shamir backups

[gmaxwell]

https://en.bitcoin.it/wiki/Shamir_Secret_Snakeoil

[Vompola]

Shamir backup basically refers to a way to divide your seed into several parts, so that the security of your wallet does not depend on just on a subject. You need to determine how many parts of Shamir backup there will be and you also need to make sure that you can recover the wallet if you have how many of those parts together.
Shamir backup is mainly used for extra security, in this process if a share is lost it does not have a bad effect and if someone gets a share it is of no use to them.

Shamir backup definitely has some security aspects and it basically removes the level of risk to another place. That does not mean that it will work like magic or can be trusted blindly.
If the required number of shares are kept by the same person or in the same place, then the additional security benefit is lost. If the shares are lost or not stored in a safe place, later access becomes much more difficult than with ordinary seeds.

I think Shamir backup is more useful for those who have large funds and it is good for those who store backups in different places. I mean Shamir backup is used for security but if users forget their saved information then it is more harmful for the user.

If someone wants to use Shamir backup then the most important thing is to test the recovery manually (on a clean device) and write down the instructions clearly, otherwise this extra complexity will eventually become the biggest weakness.

[Cricktor]

https://en.bitcoin.it/wiki/Shamir_Secret_Snakeoil

Thanks for pointing this out. I must say, I'm no crypto expert and while looking at Shamir Secret Sharing (SSS) it didn't really occur to me that implementations could be bad. I would only use open-source SSS tools and my naive approach was: it's open-source, grin, someone would spot bad code. I mostly can read code, but I'm no developer and far from being able to do something like a code audit. I would surely miss code quirks.
So much for boundless naivety.

So far I was only playing with tools like https://iancoleman.io/shamir/ or https://iancoleman.io/shamir39/ and especially the latter implementation clearly states, it's not quite for anything than experiments.

This is a prototype.

This tool should only be used for experiments.

There are no alternative implementations, meaning you are totally dependent on this tool if you use it. That is a dangerous situation to be in.

As I don't have a Trezor hardware wallet, I'm not confidently sure if a user can opt-out of SLIP-39 mnemonic recovery words with modern Trezor devices.

I will keep the outlined potential issues with SSS from the Bitcoin Wiki in mind for re-evaluation of its usefulness.

If someone wants to use Shamir backup then the most important thing is to test the recovery manually (on a clean device) and write down the instructions clearly, otherwise this extra complexity will eventually become the biggest weakness.

This is what BattleDog already wrote and isn't limited to SSS backup alone but to every backup method. If you don't check that you can recover from your backup method, you put your funds at risk. Always verify a successful recovery, no matter what!



Post edit: I hate typos and corrected what stinged my eyes now and what I missed before.

[BitBakerr1]

Shamir backup is good to use especially since it protect you very well, if a scam or thief get one part of the splitted seed phrase they can't get into your wallet however you can use 2 part of the seed phrase to get into your wallet making it look so cool meaning even if you lose some part you don't have a problem if you want to get into your wallet.
If you are interested to use this backup make sure you don't store all shares in one location because if you do and a thief gets to know the location then you are finished because they will be able to get into your wallet, don’t take photos of your shares is not necessary you need to protect them very well don't make it easy for thieves and lastly don’t type them online because we have a lot of scammers online that can hack through anything to get hold of want they want.