Create a multi-signature CCD transfer in the Desktop Wallet

A multi-signature transfer of CCD is a transaction that requires two or more co-signers to sign with their private keys to authorize the transaction.

Prerequisites

• Set up an identity and an account.

• Set up an account with multiple credentials

• Set up a LEDGER NANO device identity.

Shared accounts with multiple credentials in Desktop Wallet explains the steps involved to set up a multiple signature (shared) account.

Note

All transfers and transactions cost a fee. The fee is based on the set NRG for that transaction and the current exchange rate. The cost of transaction fees is stable in Euros, and therefore the price in CCD varies depending on the CCD to EUR exchange rate. The fee will always be deducted from the Balance of the account, so it is important to have some available CCDs to cover fees. You can see the fee in the transaction log.

Make a transfer proposal

1. Go to Multi Signature Transactions, and then select Make new proposal. All available transactions are listed in the right pane.

2. Select Send CCD.

3. Select the relevant sender account from the list of available accounts, and then select Continue. If only one account is available, this account will be selected automatically.

4. In Amount, enter the amount of CCD you want to transfer. If the amount you want to transfer including the transfer fee exceeds the amount in your account, you’ll see a message saying Insufficient funds. This means that there’s not enough CCD in the account and you’ll have to change the amount. Also, the amount must be greater than zero. In the Transaction details under Amount, you can see the estimated fee. Select Continue.

5. Select the relevant recipient from the list. If there are many recipients in the list, you can use search to find the right recipient. Select Continue.

6. Set the Transaction expiry time, leaving enough time for the co-signers to return their signatures in time, and then select Continue.

Generate the transaction

There are two ways that you can generate the transaction:

• Generate the transaction proposal without signing. This option enables you to export the transaction proposal without signing it. You don’t need a LEDGER device, but you do need an internet connection.

• Generate and sign the transaction. This option requires a LEDGER device and an internet connection.

In combination, these two options enable organizations to distribute the responsibility of creating and signing transfers among more people. It makes it possible to have one employee create the proposals and another one sign the proposals. It also makes it possible to sign the transaction on the LEDGER device in a different location than were the proposal was created.

Generate the transaction proposal without signing

1. Verify that the Transaction details are as you intended, and then select I am sure that the proposed changes are correct.

2. Select Generate without signing. You can now export the transaction proposal.

Generate and sign the transaction proposal on the LEDGER device

1. Connect the LEDGER device to the computer if you haven’t done so already. There’s a message saying Waiting for device. Please connect your Ledger.

2. Enter your PIN code on the LEDGER device. Press the buttons above the up and down arrows to choose a digit, and then press both buttons to select the digit. Press the right button to navigate to the Concordium app, and then press both buttons to open the app. The LEDGER device says Concordium is ready. Wait for the message in the Desktop Wallet saying Ledger Nano S is ready or Ledger Nano S Plus is ready.

3. In the Desktop Wallet, verify that the Transaction details are as you intended, and then select I am sure that the proposed changes are correct. (If you’re not on the proposal page, go to Multi Signature Transactions -> Your proposed transactions, and then select the proposal you want to sign.)

4. Select Generate and sign.

5. The LEDGER device says Review Transaction. Navigate to the right, till you see Sender and then an address. This is the address of the account you’re transferring CCD from.

6. Continue navigating to the right. The LEDGER device shows the Amount you’re going to transfer. Navigate to the right. The LEDGER device says Recipient and shows the recipient’s address.

7. When you’ve navigated through and verified that the information is correct, the LEDGER device says Sign transaction. Press both buttons.

8. The LEDGER device says Concordium is ready. In the Desktop Wallet, you can now see the details of the transaction proposal including how many signatures that are required before you can submit the transaction to the chain.

Export a transaction proposal

To propose a transaction to other co-signers, you have to share a file with them of the type JSON, which contains the transaction information.

1. In the Desktop Wallet, select Export transaction proposal.

2. Navigate to the location on your computer where you want to save the file. In Save as type make sure that All Files is selected. Give the file a name and the extension .json, and then click Save.

3. Send a copy of the file through a secure channel to the co-signers that must sign the transaction. Concordium recommends that you send a copy of the identicon through a secure channel that is different from the one used to send the file.

4. To print a copy of the proposal, select the printer icon in the upper-right corner, select Print to PDF, and then navigate to the place on your computer where you want to save the PDF.

Receive signatures from co-signers

When the co-signers have signed the transaction, they return the signed transaction proposal to you, and you have to import the files into the Desktop Wallet before you can submit the transaction to the blockchain.

1. If you’re still on the proposal page, go to step 3. If you left the proposal page, go to Multi-signature Transactions, and then select Your proposed transactions.

2. Select the transaction that you want to submit to the chain. You can see an overview of the transaction details and an overview of the signatures. You can also see that the status of the transaction is Unsubmitted, and you can see the identicon, and the transaction hash.

3. Select Browse to file and then navigate to the location on your computer where you saved the signed transaction file. Select the relevant file, and then select OK. The file is uploaded to the Desktop Wallet and added to the list of signatures. Alternatively, you can drag and drop the signature files from their location on the computer and on to the Desktop Wallet.

Submit the transaction to the blockchain

When you have received and added all the required signatures, you can submit the transaction to the blockchain.

1. Review the transaction details carefully to ensure that all information is correct.

2. Select I understand this is the final submission, and that it cannot be reverted.

   • If you don’t want to submit the transaction to the chain, you can select Cancel proposal. You’re asked to verify that you want to close the proposal. The proposal is still visible in the list of proposals, but it’s no longer active.

3. Select Submit transaction to chain. The transaction is submitted to the chain. After a short while, the transaction is finalized on the chain and its status changes to Finalized.

4. Select Finish to leave the page.

Warning

Transactions on the blockchain are permanent. That is, they are irreversible and can’t be deleted. Therefore, carefully review all information before you submit the transaction to the blockchain.