Is there such a thing as a 2 of 3 phone wallet. (or any x of y for mobile)

[DaveF]

Do any of the phone based wallets have such a feature. Where 3 of us can generate an address and you need 2 of us to spend it?
Looking to do a small project and it's not that we don't trust each other but the amounts at times passing though might occasionally be significant.
This just eliminates a bit of worry about any one device being compromised or someone doing something stupid.

Yeah I know we can do it with PCs and some hardware wallets but we are looking to do this a slightly different way and for the most part we are going to be doing it while mobile and phones by themselves would be the best. You might forget you ColdCard or your Trezor but you are not going to forget your phone....


-Dave

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[DaveF]

Do any of the phone based wallets have such a feature. Where 3 of us can generate an address and you need 2 of us to spend it?
Looking to do a small project and it's not that we don't trust each other but the amounts at times passing though might occasionally be significant.
This just eliminates a bit of worry about any one device being compromised or someone doing something stupid.

Yeah I know we can do it with PCs and some hardware wallets but we are looking to do this a slightly different way and for the most part we are going to be doing it while mobile and phones by themselves would be the best. You might forget you ColdCard or your Trezor but you are not going to forget your phone....


-Dave

Phones, many of them, have become trivial to hack, or exploit or take advantage of; that may be due to also ARM processor exploits, I think those have become somewhat a reality perhaps.

But I recall years ago, co pay wallet let you do what you suggest, so I imagine the bitpay wallet allows many devices; however, I havent looked at that wallet recently to see what has happened in the intervening years.

Yes they do that. I don't believe I forgot about them.
Now to spend some time testing.

Side note, was not really worried about the hacking as much as rushing to do something and screwing it up so we were wanting a 2nd set of eyes on it.

Thanks. Have a merit :-)

-Dave

[o_e_l_e_o]

You can also do with this Electrum.

When you open the Electrum app, there is an option on the landing page to set up a new "Multi-signature wallet". You can select your m-of-n configuration, and it will run through the process of generating each of you your own individual seed, and sharing your master public keys with each other. Alternatively, you could set it up on your computers, and then use the seed it gives you to import your part of the multi-sig wallet to your mobile device.

There are instructions for doing this on Electrum here: https://electrum.readthedocs.io/en/latest/multisig.html
The pictures are a little out-of-date, but the steps are the same.

[jackg]

You can also do with this Electrum.

You can only do this with android as there isn't an ios version of electrum but it works pretty well.

I used to do a 2 of 3 multisig with my laptop and phone (laptop had xprv1,xprv2,xpub3 and phone had xpub1,xprv2,xprv3) and it worked pretty well (I did it that way because I had a usb stick with xprv1,xpub2,xprv3 just in case that was made using a separate computer/os). You just generate the transaction on one device and scan it from the others once it's been signed by that device.

[DaveF]

Side note, was not really worried about the hacking as much as rushing to do something and screwing it up
-Dave

Do you have some familiarity and regularity with doing that?

Rushing and screwing something up? More times then I care to admit.

X of N wallets all the time on the PC side, never mobile which is what we are doing now.

As for Electrum we do need IOS.

-Dave

[sowns]

There’s a few multisig wallets for mobile users out there detailed here: https://www.google.com/amp/s/coinsutra.com/best-multi-signature-bitcoin-wallets/%3Famp These wallets should be enough to fulfill your needs.

[hugeblack]

I think your best chance is to use ---> https://www.bitgo.com .AFAIK It is the only web wallet that supports this feature.
In general, it seems you are safe to use this service and this is how it works.

The multisig is all handled in the backend without you having to handle private keys directly.

Read more ----> How does BitGo Multi-Sig work?
I haven't tried that wallet so it's best to research before using it.


As one member mentioned above, it is better to use Electrum but you need to deal with PC.

[o_e_l_e_o]

As one member mentioned above, it is better to use Electrum but you need to deal with PC.

No you don't. Electrum on mobile has a very straightforward wizard for setting up a multisig wallet. You can set it up on PC and import it to mobile, or even use a PC as one or more of the signatories, but you can quite happily set it all up on mobile with only mobile signatories.

And as you say, it is definitely better to use Electrum over using a web wallet.

[DaveF]

We went with the bitpay wallet.
CoPay is no longer in the play store.

Has Windows / Mac / iPhone / Android

So if we all have the our own wallet on both our phone and laptop no matter where we are we can send / receive so long as there is 2 of us.

Thanks,
Dave

[HCP]

We went with the bitpay wallet.
CoPay is no longer in the play store.

For all intents and purposes... BitPay == CoPay

Copay Wallet is no longer distributed at the Google Play Store. Bitpay Wallet is built using the same platform and code.

If you really wanted Copay, you can always try compiling it yourself: https://github.com/bitpay/copay

I used to do a 2 of 3 multisig with my laptop and phone (laptop had xprv1,xprv2,xpub3 and phone had xpub1,xprv2,xprv3) and it worked pretty well (I did it that way because I had a usb stick with xprv1,xpub2,xprv3 just in case that was made using a separate computer/os). You just generate the transaction on one device and scan it from the others once it's been signed by that device.

I'm kinda hoping you got your xprv's and xpub's a bit mixed up there... your 2-of-3 setup would be relatively useless with every device having 2x xprv's

To be an effective 2-of-3 multisig, it should be something like:
Laptop: xprv1,xpub2,xpub3
Phone: xpub1,xprv2,xpub3
USB: xpub1,xpub2,xprv3 (unless this was supposed to be your emergency recovery unit, in which case it might want 2 xprvs)

[Polina_21]

Using a multisignature wallet will make it possible. Multisignature wallet requires more than one people to authorize the Bitcoin transaction. This is referred as M-of-N transactions.
Below you can see how 2-of-3 multisig wallet works -

Creating a 2-of-3 multisig wallet can allow for an escrow transaction between two parties (Alice and Bob) that includes a third party (Charlie) as a mutually trusted arbiter in case anything goes wrong.

In such a scenario, Alice would first deposit the funds, which would be locked up (neither user being able to access them on their own). Then, if Bob provides the goods or services as agreed, they can both use their keys to sign and complete the transaction.

Charlie, the arbiter, would only need to step in if there was a dispute, at which point he could use his key to create a signature that would be provided to either Alice or Bob, according to Charlie’s judgment.

Do any of the phone based wallets have such a feature. Where 3 of us can generate an address and you need 2 of us to spend it?

There are many mobile wallets which support multisignature - Electrum, Copay, BitGo, Blocktrail, GreenAddress etc.

[Dabs]

I'd go with Electrum, but as mentioned it only has Android support and not iOS. Would it not be possible to acquire a separate Android device just for this project or is that too much to bring along? I regularly see people carry two or even 3 mobile devices.

[DaveF]

I'd go with Electrum, but as mentioned it only has Android support and not iOS. Would it not be possible to acquire a separate Android device just for this project or is that too much to bring along? I regularly see people carry two or even 3 mobile devices.

As I said above, we went with the BitPay wallet.
Since these are not scheduled transfers but more of a we need to move some BTC *now* thing always taking 2 phones with you would be a pain.

Since we went live with this (Oct 15) we have only had to transfer funds once so I can easily see the other people involved not carrying the 2nd phone after not needing it for a week....

-Dave