Atomic Swaps

In order to do an atomic swap with someone, you will first have to agree on what tokens you wish to swap. For example purposes, let's say you want to swap 40 ANON (which is the balance you should have left over after doing the payment from the previous page) for your counterparty's 20 DAWN. For this tutorial the counterparty is yourself.

To protect your anonymity from the counterparty, the swap can only send entire coins. To create a smaller coin denomination, send yourself the amount you want to swap. Then check you have a spendable coin to swap with. Note that the coin overview might look very different depending on your activity:

$ ./drk wallet --coins

 Coin            | Spent | Token ID        | Aliases | Value                    | Spend Hook | User Data | Spent TX
-----------------+-------+-----------------+---------+--------------------------+------------+-----------+-----------------
 EGV6rS...pmmm6H | true  | 241vAN...KcLssb | DRK     | 2000000000 (20)          | -          | -         | fbbd7a...5f2b19
...
 H6Bc49...Zb6k8h | false | {TOKEN2}        | DAWN    | 2000000000 (20)          | -          | -         | -
 47QnyR...1T7igm | true  | {TOKEN1}        | ANON    | 4269000000 (42.69)       | -          | -         | 47b481...b07395
 5UUJbH...trdQHY | false | {TOKEN1}        | ANON    | 4000000000 (40)          | -          | -         | -
 EEneNB...m6mxTC | false | 241vAN...KcLssb | DRK     | 1999442971 (19.97253683) | -          | -         | -

You'll have to initiate the swap and build your half of the swap tx:

$ ./drk otc init -v 40.0:20.0 -t ANON:DAWN > half_swap

Then you can send this half_swap file to your counterparty and they can create the other half and sign it by running:

$ ./drk otc join < half_swap > full_swap

They can now send it back to you. Finally, to make the swap transaction valid, you need to sign it as well

$ ./drk otc sign < full_swap > signed_swap

Now that the swap is signed, one of the parties (or a third one) must attach the corresponding fee:

$ ./drk attach-fee < signed_swap > full_swap_with_fee

Since a new call has been added to the transaction, both parties must re-sign the full_swap_with_fee file, one by one.

Party A:

$ ./drk otc sign < full_swap_with_fee > signed_full_swap_with_fee

Party B:

$ ./drk otc sign < signed_full_swap_with_fee > swap.tx

Now the complete swap transaction can be broadcasted:

$ ./drk broadcast < swap.tx

[mark_tx_spend] Processing transaction: d2a5e288e6ba44583ee12db9c7a0ed154c736d1aa841d70c7d3fa121c92dfc69
[mark_tx_spend] Found Money contract in call 0
[mark_tx_spend] Found Money contract in call 1
Broadcasting transaction...
Transaction ID: d2a5e288e6ba44583ee12db9c7a0ed154c736d1aa841d70c7d3fa121c92dfc69

On success, you should see a transaction ID. This transaction will now also be in the mempool, so you should wait again until it's confirmed.

After a while you should see the change in balances in your wallet:

$ ./drk wallet --balance

 Token ID                                     | Aliases | Balance
----------------------------------------------+---------+-------------
 241vANigf1Cy3ytjM1KHXiVECxgxdK4yApddL8KcLssb | DRK     | 19.96835727
 {TOKEN1}                                     | ANON    | 40
 {TOKEN2}                                     | DAWN    | 20

Since in this example we did an atomic swap with ourself, the balances are unchanged. We can confirm it actually happened successfully by checking our coins:

$ ./drk wallet --coins

 Coin            | Spent | Token ID        | Aliases | Value                    | Spend Hook | User Data | Spent TX
-----------------+-------+-----------------+---------+--------------------------+------------+-----------+-----------------
 EGV6rS...pmmm6H | true  | 241vAN...KcLssb | DRK     | 2000000000 (20)          | -          | -         | fbbd7a...5f2b19
...
 EEneNB...m6mxTC | true  | 241vAN...KcLssb | DRK     | 1999442971 (19.97253683) | -          | -         | d2a5e2...2dfc69
 H6Bc49...Zb6k8h | true  | {TOKEN2}        | DAWN    | 2000000000 (20)          | -          | -         | d2a5e2...2dfc69
 5UUJbH...trdQHY | true  | {TOKEN1}        | ANON    | 4000000000 (40)          | -          | -         | d2a5e2...2dfc69
 4zwzZf...uMbVir | false | {TOKEN2}        | DAWN    | 2000000000 (20)          | -          | -         | -
 BrqQuk...FcwW6d | false | {TOKEN1}        | ANON    | 4000000000 (40)          | -          | -         | -
 EEneNB...m6mxTC | false | 241vAN...KcLssb | DRK     | 1999442971 (19.96834924) | -          | -         | -

Here you can see there are two entries for the tokens we used in the swap: 40.00 ANON and 20.00 DAWN . The first entry shows the Spent flag as true and the second entry shows the Spent flag as false. This means the transaction was successful. Since we are swapping with ourself, we successfully spent the coins in the first half of the transaction, and re-minted to ourselves them in the second half of the transaction.

If you're testing atomic swaps with a counterparty and you can see their tokens, that means the swap was successful. In case you still see your old tokens, that could mean that the swap transaction has not yet been confirmed.