Or they could just use an inexpensive hardware wallet and have 2 wallets on their machine. One that is password protected and the other that needs the HW wallet. Or another form of cold storage and only move when needed.
Security protocols must be constantly updated. If we have learned anything from technology, it is that sooner or later they become obsolete. BitGrail, KuCoin, MtGox, Coincheck to mention a few, they relied too much on their security protocols, when talking about money the saying "if it ain't broke, don't fix it" is not valid.
Would not have mattered for any of those
BitGrail was 99% a inside job
MtGox was a disaster from the start with no security at all.
Coincheck did not loose
BTC they lost an alt.
KuCoin lost a bunch of different coins / tokens and while some was
BTC it was from a hot wallet that an exchange needs to function. They need to have a large amount always available to be able to function. Needing human intervention with anything means that you don't need some fancy new setup for security or ANY new setup for security. If there had to be a human there to verify the
BTC move then it would not have happened since they would have seen the issue.
-Dave
the fact of their losses is the result of non-existent or obsolete security measures, that is the strong point of this project, limiting the risk of loss, currently anyone with access to a private key can empty the wallet completely, the same with multi-signatures always 2-3, 3-5 should be used. With this project, even if a subwallet has 10000
BTC is hacked, your risk of losing will be the amount stipulated by you and not the total of the funds.
Aside from technical problem which already mentioned by @pooya87, who's the target of this security method? I expect that,
1. Regular users don't bother with such complex setup.
2. People with serious security concern already setup their airgapped/cold wallet and don't bother switch to new protocol.
3. Exchange won't find it's useful since they regularly move big amount of Bitcoin (which means they always need "master privatekey" & "master passphrase").
regular users will have the same benefits, the limit of the amount could be reduced in the aforementioned "owner's btc book" at the time of announcing that the "subwallet address" belongs to that "master privatekey". that is, if a user owns 2 BTC, he could establish that the master private key is used if the amount to be sent is equal to or greater than "0.2 btc", therefore his risk of loss is reduced to the established limit, while his master privatekey It will remain hosted, on paper, encrypted or in a hardware wallet.
You missed my point, i'm not talking about benefit for regular user, but
complexity which faced by regular user. For example,
1. Do they bother setup offline environment to create "master address"/"master privatekey"?
2. Can they remember "master passphrase", password to encrypt wallet file and different between "master"/"subwallet"?
Exchanges could increase this limit in the "owner's btc book" for example to "100 btc", if the requests for signatures with the master key is reduced, then the risk of hacking will be reduced.
That makes sense if it's possible to setup the limit without using "master privatekey".
You missed my point, i'm not talking about benefit for regular user, but complexity which faced by regular user. For example,
1. Do they bother setup offline environment to create "master address"/"master privatekey"?
was a bad formulation of what I wanted to say, the concept was edited, thanks to your comment.
2. Can they remember "master passphrase", password to encrypt wallet file and different between "master"/"subwallet"?
"Master privatekey" will only be used to sign when required, create a subwallet, certify its ownership in the "owner's btc book" and set the output limit of the "subwallet address" (without requiring the signature of the "Master privatekey").
"subwallet address": the carrier of the funds.
"master passphrase" is a unique personal key depending on the user where you want to store it, it will only be used if you lose or destroy your "subwallet privatekey".
Destroying the "subwallet privatekey" is recommended for "HODL" (you can always recover in the future with the use of "Master privatekey" + "master passphrase", when you want to spend your funds).
Destroying the "subwallet privatekey" is not recommended if you make recurring payments because it will increase the use of your "Master privatekey" and "master passphrase" to generate the "subwallet privatekey".
Exchanges could increase this limit in the "owner's btc book" for example to "100 btc", if the requests for signatures with the master key is reduced, then the risk of hacking will be reduced.
makes sense if it's possible to setup the limit without using "master privatekey".
It is not possible, if this were allowed, to modify the limit of a "subwallet address" without the signature of the "master privatekey" your funds would be at risk in their entirety.