9.4 KiB
DeepDive into Liquid: Part II - Asset Creation and Configuration
This is a multipart DeepDive that will focus on the Liquid Sidechain. It will be released in 3 Parts:
- Part I: Overview, Installation, and first Peg-In
- Part II (this): Asset Creation and Configuration
- Part III: Advanced Topics and Peg-out
Assets
In Part I, we successfully Pegged-In our BTC and received L-BTC, now lets use that L-BTC to do some interesting things with Asset Issuance:
Before we jump straight into creating an asset, let us first look at the assets we already have inside our pegged-in wallet[^1]:
$ sudo ./scripts/app compose elements exec node elements-cli -rpcuser=$E_RPCUSER -rpcpassword=$E_RPCPASS getwalletinfo
"balance": {"bitcoin": 0.00149155}`
$ sudo ./scripts/app compose elements exec node elements-cli -rpcuser=$E_RPCUSER -rpcpassword=$E_RPCPASS dumpassetlabels`
{"bitcoin": "6f0279e9ed041c3d710a9f57d0c02928416460c4b722ae3457a11eec381c526d"}
So our wallet already has an asset called 'bitcoin' and there is an associated UUID of 6f0279e9ed041c3d710a9f57d0c02928416460c4b722ae3457a11eec381c526d. Everything in Liquid is an 'Asset' (including L-BTC) and each of these Assets can have different features.
Looking up this value on https://blockstream.info/liquid/assets we can see some info about it:
This shows us the total amount of L-BTC in circulation, additionally we can see how much was Pegged-In, Out, and Burned. Most notably, this confirms that everything is in balance. The Circulating Supply = (PEG_IN - PEG_OUT - BURNED), so no debasement has happened.
Issuing our own Asset
Issuing assets is pretty straight forward
$ sudo ./scripts/app compose elements exec node elements-cli -rpcuser=$E_RPCUSER -rpcpassword=$E_RPCPASS issueasset 10 0 true
{
"txid": "8a12dd64c43de200cc7addb6c59f67bdbc6481ef1cc8b24253c7c1daba3c4e06",
"vin": 0,
"entropy": "3b8ded63f872d53d93b40ea415f3473b50c033a8e9abc1f0e7418e7f16e98dec",
"asset": "8aa889f0bd16bab7d236ab6f3583481382bf976433360ff240cf22b79181a50f",
"token": "2eb4da7c84a7b4db2944ead6b05041a5d8d8f4a73cd1413b140b44c4ec42fbdf"
}
Exploring our new Asset
- Checking out our wallet we see:
$ sudo ./scripts/app compose elements exec node elements-cli -rpcuser=$E_RPCUSER -rpcpassword=$E_RPCPASS getwalletinfo
"balance": {"8aa889f0bd16bab7d236ab6f3583481382bf976433360ff240cf22b79181a50f": 10.00000000,
"bitcoin": 0.00140447,}
- We can see our wallet has 10 of our assets[^2], lets checkout what the Liquid network knows about it:
- So publicly we know the following about our new asset:
- It cannot be re-issued (fixed supply token)
- It has only been issued once
- However both the issued amount and the circulating supply has been hidden from us.
It's nice to have hidden assets, but practically speaking they might not be useful in lots of situations. For instance, suppose that we wanted users to be able to verify the circulating amounts (i.e. to prevent debasement).
It is possible to 'unblind' this information to clients, but that would involve distributing an unblinding key to each client. Luckily there is a simple solution: we can simply issue the asset as unblinded - which will permit this information to be publicly available without affecting the security of the actual transactions:
Issuing a Non-Confidential Asset
- Let's create another address[^5] and another asset and this time choose a different option (specifically, lets create this asset unblinded):
$ sudo ./scripts/app compose elements exec node elements-cli -rpcuser=$E_RPCUSER -rpcpassword=$E_RPCPASS issueasset 10 0 false
{ "txid": "225f3ed16457467673fd64f3577031b91be370615b3feba53e1cc0b256768944", "vin": 0, "entropy": "fc4b02ee3892faaef2ddb673d437910ca75ca4d4e5ff4c1cb6ef1e3a4667a942", "asset": "41c19a473c71298a28342ccbf6fcbd3042cae8607b3b79d336b4c02e89ba2c66", "token": "10178003de4d2141fc318e3a61a7c8e1d43d3842a87fb8fb18fc1c1b09d081cb" }
...and checking again what the Liquid network knows about it
-
Now we can see the total issued amount / supply[^2]
-
Let's try sending 2 of these unblinded assets to another wallet (my Blockstream Green mobile wallet) and see what is visible on the network.
$ sudo ./scripts/app compose elements exec node elements-cli -named -rpcuser=$E_RPCUSER -rpcpassword=$E_RPCPASS sendtoaddress address="VJLKDWB..." amount=2.0 assetlabel="41c19a..."`
b1d0592319fc5a6ed4e2ea912ddbc9e630e0a13a083a178f69054129ef589d25
- Looking up this transaction on the block explorer, we see:
This is interesting: So although the transaction is visible, we can't see what was actually transferred (even though the details of the asset are visible, it is still hidden inside the transaction). Further, where is my Green Wallet address (ie. VJLKDWB...)? We can see 3 output addresses, presumably these are: Change, Fee, and Recipient...but where the actual Green Wallet address?
- Let's look up my Green Wallet address directly in the explorer:
So now this shows us that the Confidential Address: VJLKDWB... corresponds to the Unconfidential Address: GnDXE5... Through the magic of one-way hashes, if we know the "Confidential" address we can then derive its public address. However, just by looking at the public blockchain, there is no way to reverse that hash.
Now, lets look at how things look on the Green mobile wallet:
We can see that we've received 200,000,000 'sats' of our custom asset. However, notice how there is no label. Whereas, for L-BTC and Tether it shows complete with name and ticker symbol. Showing just the contract address is not very user friendly. Let's see if we can remedy.
Registering our Asset
The publication of asset metadata info on Liquid works on a .well-known system where specific files are published on a webserver that you control. There are a few different steps to accomplish this, so lets begin
- Lets set a few environmental variables to make things easier:
$ export ASSET_REGISTRY_URL="https://assets.blockstream.info/"
$ export DOMAIN="coins.b0xxy.net" #NOTE: Needs to match what was in Contract Hash
$ export ASSET="41c19a473c71298a28342ccbf6fcbd3042cae8607b3b79d336b4c02e89ba2c66" #NOTE: Needs to match the asset you are registering
$ echo "Authorize linking the domain name $DOMAIN to the Liquid asset $ASSET" > liquid-asset-proof-$ASSET
Running the above will result in a file named liquid-asset-proof-41c19a... being created, and inside that file it will say Authorize linking the domain name coins.b0xxy.net to the Liquid asset 41c19a...
First you need to place this liquid-asset-proof file in the root directory of your domain under a folder named .well-known
Before you proceed to the next step, please verify that they above file is reachable. Go to an external machine and issue:
$ curl https://nulldata.org/.well-known/liquid-asset-proof-409b1d0cb614822ea703576b71958ab051d66ff6708b368f378f2ffea458d15a
...and it should output the Authorize linking the domain text.
- We can validate our request before submitting to make sure everything is correct
$ curl https://assets.blockstream.info/contract/validate -H 'Content-Type: application/json' -d '{"contract": '$CONTRACT', "contract_hash": "2b14c6c7ff4009ce6cf4dfa59099fdda4f27459d153b45fe91790e9d1bca42a0"}'
valid
Since everything looks ok, we can submit:
$ curl https://assets.blockstream.info/ --data-raw '{"asset_id":"409b1d0cb614822ea703576b71958ab051d66ff6708b368f378f2ffea458d15a","contract":{"entity":{"domain":"coins.b0xxy.net"},"issuer_pubkey":"02ada219afbd424afca568e01370161d68ab3aa0697cd759a6105c23b81d20b397","name":"StackerNewsDemo-1","precision":8,"ticker":"SND-1","version":0}}'
* Now we can push the data to blockstreams server, lets create a script:
` $ echo "curl $ASSET_REGISTRY_URL --data-raw '{\"asset_id\":\"$ASSET\",\"contract\":$CONTRACT}'" > register-asset.sh`
Verify that this script looks sane, mark it as executable and run it.
[^1]: The values E_RPCUSER and E_RPCPASS, where environmental variables we set in Part I
[^2]: Like in bitcoin, 1 integer unit is 100,000,000 base units (not sats, but equivalent concept) - So in this case issuing "10" assets is really issuing 1,000,000,000 units (10 x 100,000,000).
[^3]: Technically just running `elements-cli issueasset 10 0` is enough to issue an asset, however there will be limitations later on when trying to register the asset, burn, remove, etc.
[^4]: Using a legacy address for this task imposes no real implications to your security since its only used to remove assets from the registry. Its possible to do this with a non-legacy address, but more steps are involved and we will need to use other tools rather than what's already built-in to Elements node, so we will just use a legacy address for this.
[^5]: So each asset is held in a separate address