M/N Multisig

First, the wallet to be converted to multisig must be empty. It is best to use a brand-new wallet for the purpose, although not required. It is strongly advised to make a copy of the wallet files first, just in case something goes wrong.

Overview

In short, the process is:

Wallet Creation

All parties command prepare_multisig and send data to ALL other parties
All parties command make_multisig <threshold> <data1> <data2> .... <dataN> and send 2nd batch of data to ALL other parties
All parties command finalize_multisig <data1> <data2> ...... <DataM> with the data from ALL other parties.

Receiving

All parties can type address to see the created multisig wallet address. The address will, of course, be the same for all parties since they're all watching the same wallet.

Preparation for Sending

To prepare for sending all parties command export_multisig_info <filename> and send the file to all other parties
To complete preparation, all parties command import_multisig_info <filename1> <filename2> ..... <filenameM> and import files from other parties

Sending

To send, any party can use the usual transfer command, but the result will be a file named multisig_beldex_tx which must be sent to any 1 other signer
The other party commands sign_multisig multisig_beldex_tx and the file is updated with the signature.
The completely signed file is pushed to the network with use of submit_multisig multisig_beldex_tx.

Below is a step-by-step walkthrough.

Wallet Creation

Requirements:

N empty beldex-wallet-cli wallets.
All parties wallets connected to a beldexd.
Confidential communication channel.

Step 1 - Prepare Multisig

All N people should open up their beldex-wallet-cli and generate a new wallet. Make sure you do not have any $beldex within your wallet.

The 1st, 2nd, 3rd, and so on, up to the Nth person commands in their beldex-wallet-cli:

prepare_multisig

The output will be something like:

MultisigV1cR7X7ZAfa5ncRmQv1hpt4P1DmmnhinhokhDMqsmuWXmHFrb6xUr3FtBGygCfMScxnKJvXK1vvPNahXNWfYWVquieBErr98sFtgs24c2YuYrQT78uxV8oYx1A9bKeHSUfYzCniN5kMznEfvKCw3FiomjLvw364gg98ZWp16zA7pUVozid  
Send this multisig info to all other participants, then use make_multisig <threshold> <info1> [<info2>...] with others' multisig info  
This includes the PRIVATE view key, so needs to be disclosed only to that multisig wallet's participants

Copy the entire line Multisig…...Vozid and be sure to capture the whole thing when copying.

Each person must send their Multisig…...arg to each other person, it is suggested to send this information through a confidential comunication channel.

Step 2 - Make Multisig

All N people now have the Multisig...arg text from the other N-1 people. With that, each of them can create their part of the multisig wallet. Before you proceed, note that the wallet will lose access to the underlying wallet when converted to multisig. This is not really a problem, since we started with an empty wallet, and if all goes OK with this step, you won't ever need it unless you want to go through the process again for whatever reason (like HDD died, but you have the seed mnemonic of the underlying wallet and want to reconstruct the multisig wallet).

Person 1 commands:

make_multisig <threshold> <data person 2> <data person 3> ..... <data person N>

Where <threshold> is the number of signers required out of the N people, <data person 2>is the output provided by Person 2, and <data person 3> is the output provided by Person 3, and <data person N> is the output provided by the Nth person.

This is the process for M of N multisig wallets, For the below example we will show a 2 of 3 multisig wallet.

This should look similar to:

make_multisig 2 MultisigV12EHtuvxFyAYDNcDsbDqWHDfkRr4JZchSdf8eZQSFwiMKDk15CYEJeQyEwtSnqUZdRr2BsEaT9z2biUdDTEQM4T3N625owvKMDoyhbRj3bwkBtceLKimap8DBAiUmSABpdf62HnPYiRtLW4JdVFmfqjndhWjYBypx1duvpi3qwfSrBY9a MultisigV1TqQ8Gt5Sb3GYtVJa1fQrK7e7hPm59XbooNvLxPSBR4856bW9jtD1hEyWy4yULKrX7reZZ6vrKdBCdSdk4nfApCGYJAA2WP4pKNwHDyKTuLEeuoDhqno8keEVeEF9AZsWXvng1avUTRREmy11h8wu8pdjopC4AguQKiHCJCN7aT9W6b8C

Notice how there are 2 strings starting with Multisig....arg. One is from person 2 and other from person 3, if their is 5 different people their would be 4 different strings of Multisig....arg. The number at the beginning is the minimum required number of signatures. Since it's a 2/3 scheme - it's 2.

To reiterate, for a 5/8 scheme which means there are 8 people who can sign and 5 people must sign to authorise a transaction out of the Multi signature wallet. In this circumstance, the command each person would run has a <threshold> that equals 5 and 7 strings of multisig...arg.

The output from the make_multisig command will be similar to:

Another step is needed  
MultisigxV1PKCwmVrucV8bXi18VnHFqRXcnAq4osFL3ahzPHCiN48zhs28u6jmEhy7ktZbUEGfRtTuFjjKzJYb61fnFwnysBBnNXsUtCgFMXPa7FyNKVy2AnUg3ePEnKqWkgKVvA81axTS8r9EX1DmVPXgFKkFzw4Yj4ZtMcJVo77b5ayuMzjFtsaijko9X2bjd9AVfFVGBFMCSLa4xXhNVNz19CTUJx5gpoPG  
Send this multisig info to all other participants, then use finalize_multisig <info1> [<info2>...] with others' multisig info

With any M of N schemes there's an additional step to be done here. The new Multisig...arg info that was just outputted must be passed to ALL other participants (For person 1 they must send it to persons 2 & 3 ... all the way up to person N).

Persons N sends the new output to all other persons.

Step 3 - Finalize Multisig

Here we do one last command to make the wallet ready for receiving. It requires the 2nd batch of Multisig…....arg strings received from other parties.

Person N will run the command:

finalize_multisig MultisigxV1Vg1tsRLurvAc5aSA9Hd9God3MQhijCFoE1rPDFzx7ufwhs28u6jmEhy7ktZbUEGfRtTuFjjKzJYb61fnFwnysBBnfYm4xJWcJ4qM4khSb2KkyAKDuT39pTvdmemhojNjeYCmgSQ1NZLyBj48R1tVpiGNxa7TDnGbSgLuKBq35AX6jfu5PECAcDDn22CFQbJZip7xnBbn89Szzh27xeozfxcLiqqm MultisigxV14xDZBGACz3iUh2aVKGE5q5VzcvJdg2qCvZECgUWCdy5QNXsUtCgFMXPa7FyNKVy2AnUg3ePEnKqWkgKVvA81axTSfYm4xJWcJ4qM4khSb2KkyAKDuT39pTvdmemhojNjeYCmCNaRSsDEcemLLL8wCvzsy5R6hhkhWLYkD9vhZwprSFFKMZ7tfRko2VfMBoKQhB7PKXbf1npk2xceVKu2y7kExywb

Unfortunately the wallet will not display an output at this point. There's no indication that the process was successfully completed (for now). All N persons do the same, and all N wallets will show the same address after this step.

Now each person run the command:

address

And each N people of the multisig wallet should be shown the same address in their wallet.

Receiving

Step 1 Fund The Multisig Account

This is simple, just send to the shared address. You can send multiple times, just like a normal wallet. You can use payment ID’s as well, or generate an integrated address to receive funds.

Best part, whomever is sending the funds won't be able to tell that the address belongs to a multisig wallet since it looks like any other Beldex address.

Step 2 Check Multisig Account Balance

Just open the wallet and run the refresh command. Once completed, all persons can verify that the funds arrived.

Person 1, 2, 3 up to N can run the command:

show_transfers

To see incoming transfers or the following command to see the balance of the wallet:

balance

Preparation for Spending

Step 1 - Export Multisig

Without this step, it will not be possible to create a transaction that spends Beldex. As a minimum, the sender needs to get a partial key image from all the people who will sign the transaction with them later. They could get it from the parties immediately and then later decide with whom to sign.

Person N commands:

export_multisig_info miN

Where miN can be any filename. The output will be:

Multisig info exported to miN

The file miN will be located in the shell working folder*

Person N sends that file to other people. Persons 2 & 3 up to N do the same.

Optional: Step 1.2 Sending Multisig Info File with terminal - transfer.sh

It is optional to use the terminal to send each person the multisig info files.

UPLOADING MULTISIG INFO FILE

Person 1 will open up a new terminal and change to the directory mi1 has been saved.*

Person 1 will run the following command:

curl --upload-file ./mi1 https://transfer.sh/mi1

Person 1 will receive the link to the file as an output, looking similar to:

https://transfer.sh/Ehl5q/mi1

Person 1 will need to send this link to Person 2, Person 3, .... Person N. Person 2 will need to do the same and send the link to Person 1, 3 ..... N. Person 3 will need to do the same and send the link to Person 1, 2 ..... N. Person N will need to do the same and send the link to Person 1, 2, 3, 4, 5 ...... N-1.

DOWNLOADING MULTISIG INFO FILE

Person 1 should change to the directory of their beldex-wallet-cli and use Person 2, 3, 4 ... N’s download link to run the commands:

curl <link> -o <filename>

Replacing <link> with the link Person 2, 3 ... N shared with Person 1 and <filename> with the filename of the Multisig info file that Person 2, 3 or ... N generated, for example Person 1 will run the command:

curl https://transfer.sh/Iedv9/mi2 -o mi2

And the command:

curl https://transfer.sh/dfvr3/mi3 -o mi3

and all the way up to:

curl https://transfer.sh/dfvr3/mi3 -o miN

Likewise, Person 2, 3 .... and N should do the same, changing directories to their beldex-wallet-cli and downloading with the alternative Persons download link, and filename.

curl https://transfer.sh/Ehl5q/mi1 -o mi1

Step 2 - Import Multisig

Now, they must all import each other's file so they can be ready to make a TX later.

For example, Person 2 commands:

import_multisig_info mi1

import_multisig_info mi3

import_multisig_info miN

The wallet will look for files in the shell working folder* and if the files are found the output will look like:

2 outputs found in mi1  
Height 56156, transaction <88ba687dc79a0b39e6de6d0763eda8363d33d9f58ec9a096171bd9a7f1dae873>, received 0.100000000000  
Height 56156, transaction <d6ac845b9400759525519cdc5d514eb8f5b1d265b24d1c016e75b20ed3b4b7da>, received 0.100000000000

Persons 1, 3 .... and N do the same.

Spending

Step 1 - Transfer (Preparing Unsigned Transaction)

Any of the multisig wallets can start a transaction, it doesn't matter. To avoid weird things from happening only do it for 1 transaction at a time. If anything weird happens, do the step 1 & 2 again to fix.

For example, let's say that Person 3 will make the TX.

Person 3 performs the usual transfer command:

transfer bxTmZX8EzZVjS9zNg7zAsrEQFDgcVC2qV2ZMyoWsbyK4SNB2SwMHZtMhPSsFyTmRBQUaGVF5k3qy5CMFM6Lvj7gi3AeszDag7 50

The output will look like:

Unsigned transaction(s) successfully written to file: multisig_beldex_tx

Check in the folder where you started beldex-wallet-cli from. There should be a file named multisig_beldex_tx.

Send the file multisig_beldex_tx to one of the people who will sign the TX.

Person 3 will send the file multisig_beldex_tx to the Person 1, 2 or N. Person 3 can send this file through email or alternatively use the transfer.sh commands outside of the wallet:

curl --upload-file ./multisig_beldex_tx https://transfer.sh/multisig_beldex_tx

If Person 3 chooses to use transfer.sh command to send the file to Person 1 or 2 they will receive a <link>.

Person 1 or 2 must finish the signature. Person 1 or 2 copies/downloads the file to the same folder from where he started (or will start) beldex-wallet-cli.

Person 1 or 2 can run the command to download the file to the beldex-wallet-cli directory.

curl https://transfer.sh/CJqnM/multisig_beldex_tx -o multisig_beldex_tx

Replacing https://transfer.sh/CJqnM/multisig_beldex_tx with the link provided by Person 3.

Step 2 - Sign Multisig

Let's say Person 2 was picked as the partner. They must finish the signature. Person 2 copies the file to the same folder from where he started (or will start) beldex-wallet-cli.

Then, Person 2 commands:

sign_multisig multisig_beldex_tx

and they will be prompted to check it first:

Loaded 1 transactions, for 108.082287779, fee 0.061108880, sending 50.000000000 to bxTmZX8EzZVjS9zNg7zAsrEQFDgcVC2qV2ZMyoWsbyK4SNB2SwMHZtMhPSsFyTmRBQUaGVF5k3qy5CMFM6Lvj7gi3AeszDag7, 58.021178899 change to bxScXhWpAG2aUHmFemwvn4HddHA5GQ4u6MvYsW2hVteJSwLJXCEhk2aVp4XzyqGmvyUqc3w8fwWwg6szGEytUSx51C6WQ3er8, with min ring size 10, no payment ID.

Is this okay? (Y/Yes/N/No):

If ok, answer Y, and the output will look like:

Transaction successfully submitted, transaction <3b03b16c79eaa5564171ae88242c4cdb1f9e0b41fc3de949c6524c5026a3f3bb>

If the threshold is greater than 2 another multisig_beldex_tx file will need to be signed by the amount of signers required.

Step 3 - Submit Multisig

Finally, person with the final signed file submits the transaction to the network by commanding:

submit_multisig multisig_beldex_tx

There will be a confirmation prompt:

Loaded 1 transactions, for 108.082287779, fee 0.061108880, sending 50.000000000 to bxTmZX8EzZVjS9zNg7zAsrEQFDgcVC2qV2ZMyoWsbyK4SNB2SwMHZtMhPSsFyTmRBQUaGVF5k3qy5CMFM6Lvj7gi3AeszDag7, 58.021178899 change to bxScXhWpAG2aUHmFemwvn4HddHA5GQ4u6MvYsW2hVteJSwLJXCEhk2aVp4XzyqGmvyUqc3w8fwWwg6szGEytUSx51C6WQ3er8, with min ring size 10, no payment ID.

Is this okay? (Y/Yes/N/No):

If ok, answer Y, and the transaction will be sent. The output will look like:

Transaction successfully submitted, transaction <3b03b16c79eaa5564171ae88242c4cdb1f9e0b41fc3de949c6524c5026a3f3bb>

You can check its status by using the show_transfers command.

The person 2 could also send the signed TX to person 3, who could then submit it to the network himself.

If you want to make another one, you have to go back to preparation for spending step (sync the key images again).

The wallet will look for the files and export them to the folder from where it was started, ie where your command prompt / shell was when you called beldex-wallet-cli. It may or may not be the same folder as your actual wallet files or beldex-wallet-cli, depending on how you go about it.
For example, your wallet could be on some USB drive like f:\temp\, and your wallet software on c:\beldex\ and your shell working folder could be c:\.
If you remain in c:\ with the shell, you could start the wallet by its full path and specify the wallet file location: c:\beldex\beldex-wallet-cli.exe --wallet-file f:\temp\mywallet. In this case, all the import/export stuff would be read/written to c:\because that's still your shell's working folder.
It would be probably feel more natural to cd into the wallet folder. Do f: to change drive and then cd f:\temp\. Then, simply start the wallet from that location by its full path again: c:\beldex\beldex-wallet-cli.exe --wallet-file mywallet. Notice how you don't have to write the full wallet path now as you're already there with your shell. In this case, all the files mentioned above would be written or read from the same folder as the wallet files.

Source:

Monero Stack Exchange: how to use monero multisigniture wallets

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