Add calculation of elements AssetId

Author: philipr-za

src/issuance.rs

@@ -16,12 +16,13 @@
 
 use std::io;
 use std::str::FromStr;
-
 use crate::encode::{self, Encodable, Decodable};
 use crate::hashes::{self, hash_newtype, sha256, sha256d, Hash};
 use crate::fast_merkle_root::fast_merkle_root;
 use secp256k1_zkp::Tag;
+use crate::genesis::{commit_to_custom_network_parameters, NetworkParams};
 use crate::transaction::OutPoint;
+use crate::Txid;
 
 /// The zero hash.
 const ZERO32: [u8; 32] = [
@@ -75,8 +76,16 @@ impl AssetId {
         0x3d, 0x1c, 0x04, 0xed, 0xe9, 0x79, 0x02, 0x6f,
     ]));
 
+    /// The asset ID for L-BTC, Bitcoin on the Liquidtestnet network.
+    pub const LIQUIDTESTNET_BTC: AssetId = AssetId(sha256::Midstate([
+        0x49, 0x9a, 0x81, 0x85, 0x45, 0xf6, 0xba, 0xe3,
+        0x9f, 0xc0, 0x3b, 0x63, 0x7f, 0x2a, 0x4e, 0x1e,
+        0x64, 0xe5, 0x90, 0xca, 0xc1, 0xbc, 0x3a, 0x6f,
+        0x6d, 0x71, 0xaa, 0x44, 0x43, 0x65, 0x4c, 0x14,
+    ]));
+
     /// Create an [`AssetId`] from its inner type.
-    pub const fn from_inner(midstate: sha256::Midstate) -> AssetId {
+    pub fn from_inner(midstate: sha256::Midstate) -> AssetId {
         AssetId(midstate)
     }
 
@@ -146,6 +155,31 @@ impl AssetId {
     pub fn into_tag(self) -> Tag {
         self.0.to_byte_array().into()
     }
+
+    /// Pegged asset id for given network parameters
+    pub fn pegged_asset_id_for_network_params(params: &NetworkParams) -> Option<AssetId> {
+        match params.network_id.as_str() {
+            "liquidv1" => Some(Self::LIQUID_BTC),
+            "liquidtestnet" => Some(Self::LIQUIDTESTNET_BTC),
+            _ => {
+                // Else calculate the asset_id
+                let asset_id = Self::pegged_asset_id_for_params_and_parent_chain_hash(
+                    params,
+                    bitcoin::Network::Regtest.chain_hash(),
+                );
+                Some(asset_id)
+            }
+        }
+    }
+
+    /// Calculate the `AssetId` for the pegged asset for a given set of network parameters assuming
+    /// a Regtest parent network
+    fn pegged_asset_id_for_params_and_parent_chain_hash(params: &NetworkParams, parent_chainhash: bitcoin::blockdata::constants::ChainHash) -> AssetId {
+        let commit = commit_to_custom_network_parameters(params);
+        let asset_outpoint = OutPoint::new(Txid::from_slice(commit.as_slice()).expect("txid"), 0);
+        let asset_entropy = AssetId::generate_asset_entropy(asset_outpoint, ContractHash::from_slice(parent_chainhash.to_bytes().as_slice()).unwrap());
+        AssetId::from_entropy(asset_entropy)
+    }
 }
 
 impl ::std::fmt::Display for AssetId {
@@ -260,7 +294,7 @@ impl<'de> ::serde::Deserialize<'de> for AssetId {
 mod test {
     use super::*;
     use std::str::FromStr;
-
+    use bitcoin::constants::ChainHash;
     use crate::hashes::sha256;
 
     #[test]
@@ -366,4 +400,52 @@ mod test {
             "6f0279e9ed041c3d710a9f57d0c02928416460c4b722ae3457a11eec381c526d",
         );
     }
+
+    #[test]
+    fn liquid_asset_ids() {
+        // Testing the two most common Regtest networks using in Liquid and CLN codebases
+        let network_params = NetworkParams::custom_network("elementsregtest".to_string(), None, None, None);
+        let asset_id = AssetId::pegged_asset_id_for_params_and_parent_chain_hash(
+            &network_params,
+            bitcoin::Network::Regtest.chain_hash(),
+        );
+
+        let elementsregtest_asset_id = AssetId(sha256::Midstate([
+            0x23, 0x0f, 0x4f, 0x5d, 0x4b, 0x7c, 0x6f, 0xa8, 0x45, 0x80, 0x6e, 0xe4,
+            0xf6, 0x77, 0x13, 0x45, 0x9e, 0x1b, 0x69, 0xe8, 0xe6, 0x0f, 0xce, 0xe2,
+            0xe4, 0x94, 0x0c, 0x7a, 0x0d, 0x5d, 0xe1, 0xb2,
+        ]));
+
+        assert_eq!(asset_id, elementsregtest_asset_id);
+
+        let network_params = NetworkParams::custom_network("liquid-regtest".to_string(), None, None, None);
+        let asset_id = AssetId::pegged_asset_id_for_params_and_parent_chain_hash(
+            &network_params,
+            bitcoin::Network::Regtest.chain_hash(),
+        );
+
+        let liquid_regtest_assetid = AssetId(sha256::Midstate([
+            0x5c, 0xe7, 0xb9, 0x63, 0xd3, 0x7f, 0x8f, 0x2d, 0x51, 0xca, 0xfb, 0xba,
+            0x92, 0x8a, 0xaa, 0x9e, 0x22, 0x0b, 0x8b, 0xbc, 0x66, 0x05, 0x71, 0x49,
+            0x9c, 0x03, 0x62, 0x8a, 0x38, 0x51, 0xb8, 0xce,
+        ]));
+
+        assert_eq!(asset_id, liquid_regtest_assetid);
+
+        let liquidv1_params = NetworkParams::liquidv1();
+        let asset_id = AssetId::pegged_asset_id_for_params_and_parent_chain_hash(
+            &liquidv1_params,
+            bitcoin::Network::Bitcoin.chain_hash(),
+        );
+
+        assert_eq!(asset_id, AssetId::LIQUID_BTC);
+
+        let liquidtestnet_params = NetworkParams::liquidtestnet();
+        let asset_id = AssetId::pegged_asset_id_for_params_and_parent_chain_hash(
+            &liquidtestnet_params,
+            ChainHash::from([0u8; 32]),
+        );
+
+        assert_eq!(asset_id, AssetId::LIQUIDTESTNET_BTC);
+    }
 }