bitcoin-s/website/versioned_docs/version-0.3.0/applications/dlc.md
Nadav Kohen a503441619 Crypto Project Refactor (#1380)
* Added crypto project and decoupled BitcoinSLogger from NetworkElement

Decoupled BitcoinSLogger from Factory

Moved NetworkElement into crypto project

Moved Factory and BitcoinSUtil (renamed to BytesUtil) to crypto project

Moved MaskedToString to crypto project

Added BytesUtil to imports and cleaned up CryptoUtil.recoverPoint

Moved the rest of crypto stuff to the crypto project

Moved crypto tests to crypto-test project

* Added documentation for crypto project
2020-04-30 12:34:53 -05:00

165 lines
7 KiB
Markdown

---
id: version-0.3.0-dlc
title: Executing A DLC with Bitcoin-S
original_id: dlc
---
## Executing A Discreet Log Contract (DLC)
## Step 1: Get Bitcoin-S Setup
See the [setup document](../getting-setup).
Make sure to follow [Step 4](../getting-setup#step-4-optional-discreet-log-contract-branch) to checkout the `dlc` feature branch.
## Step 2: Agree On Contract Terms
Both parties must agree on all fields from the table below:
| Field Name | Format |
| :------------: | :------------------------------------------------------: |
| oracleInfo | OraclePubKeyHex ++ OracleRValueHex |
| contractInfo | Hash1Hex ++ 8ByteValue1Hex ++ Hash2Hex ++ 8ByteValue2Hex |
| collateral | NumInSatoshis |
| locktime | LockTimeNum |
| refundlocktime | LockTimeNum |
| feerate | NumInSatoshisPerVByte |
Here is an example `oracleInfo` for public key `025acb434efb32bbf7ca7fd44b22e0f3f5570c6bc564e6059b03ba18c277054ac1` and R value `03f8758d7f03a65b67b90f62301a3554849bde6d00d50e965eb123398de9fd6ea7`:
```bashrc
025acb434efb32bbf7ca7fd44b22e0f3f5570c6bc564e6059b03ba18c277054ac103f8758d7f03a65b67b90f62301a3554849bde6d00d50e965eb123398de9fd6ea7
```
Here is an example `contractInfo` for hashes `c07803e32c12e100905e8d69fe38ae72f2e7a17eb7b8dc1a9bce134b0cbe920f` and `5c58e41254e7a117ee1db59874f2334facc1576c238c16d18767b47861f93f7c` with respective Satoshi denominated outcomes of `100000 sats` and `0 sats`:
```bashrc
c07803e32c12e100905e8d69fe38ae72f2e7a17eb7b8dc1a9bce134b0cbe920fa0860100000000005c58e41254e7a117ee1db59874f2334facc1576c238c16d18767b47861f93f7c0000000000000000
```
And finally, here are the oracle signatures for each hash in order in case you want to test with this contract:
```bashrc
f8758d7f03a65b67b90f62301a3554849bde6d00d50e965eb123398de9fd6ea7fbbee821b7166028a6927282830c9452cfcf3c5716c57e43dd4069ca87625010
```
```bashrc
f8758d7f03a65b67b90f62301a3554849bde6d00d50e965eb123398de9fd6ea7af05f01f1ca852cf5454a7dc91cdad7903dc2e67ddb2b3bc9d61dabd8856aa6a
```
Note: if you wish to setup your own oracle for testing, you can do so by pasting the following into the `sbt core/console`:
```scala
import org.bitcoins.core.crypto._
import org.bitcoins.core.currency._
import org.bitcoins.crypto.CryptoUtil
val privKey = ECPrivateKey.freshPrivateKey
val pubKey = privKey.publicKey
val nonce = SchnorrNonce.freshNonce
val rValue = nonce.publicKey
val winHash = CryptoUtil.sha256(ByteVector("WIN".getBytes)).flip
val loseHash = CryptoUtil.sha256(ByteVector("LOSE".getBytes)).flip
(pubKey.bytes ++ rValue.bytes).toHex
(winHash.bytes ++ Satoshis(100000).bytes ++ loseHash.bytes ++ Satoshis.zero.bytes).toHex
Schnorr.signWithNonce(winHash.bytes, privKey, nonce).hex
Schnorr.signWithNonce(loseHash.bytes, privKey, nonce).hex
```
Where you can replace the messages `WIN` and `LOSE` to have the oracle sign any two messages, and replace `Satoshis(100000)` and `Satoshis.zero` to change the outcomes.
## Step 3: Setup The DLC
### Creating The Offer
Once these terms are agreed to, either party can call on `createdlcoffer` with flags for each of the fields in the table above. For example:
```bashrc
./app/cli/target/graalvm-native-image/bitcoin-s-cli createdlcoffer --oracleInfo 025acb434efb32bbf7ca7fd44b22e0f3f5570c6bc564e6059b03ba18c277054ac103f8758d7f03a65b67b90f62301a3554849bde6d00d50e965eb123398de9fd6ea7 --contractInfo c07803e32c12e100905e8d69fe38ae72f2e7a17eb7b8dc1a9bce134b0cbe920fa0860100000000005c58e41254e7a117ee1db59874f2334facc1576c238c16d18767b47861f93f7c0000000000000000 --collateral 40000 --locktime 1666720 --refundlocktime 1666730 --feerate 3
```
This will return a nice pretty-printed JSON offer. To get an offer that can be sent to the counter-party, add the `--escaped` flag to the end of this command.
### Accepting The Offer
Upon receiving a DLC Offer from your counter-party, the following command will create the serialized accept message:
```bashrc
./app/cli/target/graalvm-native-image/bitcoin-s-cli acceptdlcoffer --offer [offer] --escaped
```
### Signing The DLC
Upon receiving a DLC Accept message from your counter-party, the following command will generate all of your signatures for this DLC:
```bashrc
./app/cli/target/graalvm-native-image/bitcoin-s-cli signdlc --accept [accept] --escaped
```
### Adding DLC Signatures To Your Database
Upon receiving a DLC Sign message from your counter-party, add their signatures to your database by:
```bashrc
./app/cli/target/graalvm-native-image/bitcoin-s-cli adddlcsigs --sigs [sign]
```
You are now fully setup and can generate the fully signed funding transaction for broadcast using
```bashrc
./app/cli/target/graalvm-native-image/bitcoin-s-cli getdlcfundingtx --eventid [eventid]
```
where the `eventid` is in all but the messages other than the DLC Offer message, and is also returned by the `adddlcsigs` command.
## Step 4: Executing the DLC
### Mutual Close
Upon receiving an oracle signature, either party can initiate a mutual close with
```bashrc
./app/cli/target/graalvm-native-image/bitcoin-s-cli initdlcmutualclose --eventid [eventid] --oraclesig [sig] --escaped
```
And if you receive one of these CloseSig messages from your counter-party, you can generate the fully-signed mutual closing transaction with
```bashrc
./app/cli/target/graalvm-native-image/bitcoin-s-cli acceptdlcmutualclose --closesig [closesig]
```
### Unilateral Close
If your counter-party is unresponsive upon receiving an `initdlcmutualclose` message, or is unreachable, you can execute the DLC unilaterally with
```bashrc
./app/cli/target/graalvm-native-image/bitcoin-s-cli executedlcforceclose --eventid [eventid] --oraclesig [sig]
```
which will return two fully-signed transactions in the case that you are owed any funds, and one fully-signed transaction in the case that you aren't. The first transaction returned should be the fully signed Contract Execution Transaction, and the second transaction, if existing, should be the fully-signed sweep transaction which claims your funds on the CET.
#### Claiming Remote Funds When Counter-Party Unilaterally Closes
If your counter-party has broadcasted a CET to the network, you can claim the funds on the `ToRemoteOutput` using
```bashrc
./app/cli/target/graalvm-native-image/bitcoin-s-cli claimdlcremotefunds --eventid [eventid] --forceclosetx [cet]
```
#### Claiming Penalty Funds
If your counter-party has broadcasted a CET to the network, and does not sweep their ToLocal funds in `5` blocks, you can claim the funds on the `ToLocalOutput` using
```bashrc
./app/cli/target/graalvm-native-image/bitcoin-s-cli claimdlcpenaltyfunds --eventid [eventid] --forceclosetx [cet]
```
### Refund
If the `refundlocktime` for the DLC has been reached, you can get the fully-signed refund transaction with
```bashrc
./app/cli/target/graalvm-native-image/bitcoin-s-cli executedlcrefund --eventid [eventid]
```