ELIP-0100 implementation

as defined in https://github.com/ElementsProject/ELIPs/blob/main/elip-0100.mediawiki
but excluding contract validation since:
- it will go in a standalone elip
- requires other deps, in particular for domain validation

Author: RCasatta

src/pset/elip100.rs

@@ -0,0 +1,281 @@
+//!
+//! An implementation of ELIP0100 as defined in
+//! <https://github.com/ElementsProject/ELIPs/blob/main/elip-0100.mediawiki>
+//! but excluding contract validation.
+//!
+//! ELIP0100 defines how to inlcude assets metadata, such as the contract defining the asset and
+//! the issuance prevout inside a PSET
+//!
+//! To use check [`PartiallySignedTransaction::add_asset_metadata`] and
+//! [`PartiallySignedTransaction::get_asset_metadata`]
+//!
+
+use std::io::Cursor;
+
+use super::{raw::ProprietaryKey, PartiallySignedTransaction};
+use crate::{
+    encode::{self, Decodable, Encodable},
+    AssetId, OutPoint,
+};
+
+/// keytype as defined in ELIP0100
+pub const PSBT_ELEMENTS_HWW_GLOBAL_ASSET_METADATA: u8 = 0x00u8;
+
+/// Prefix for PSET hardware wallet extension as defined in ELIP0100
+pub const PSET_HWW_PREFIX: &[u8] = b"pset_hww";
+
+/// Contains extension to add and retrieve from the PSET contract informations related to an asset
+impl PartiallySignedTransaction {
+    /// Add contract information to the PSET, returns None if it wasn't present or Some with the old
+    /// data if already in the PSET
+    pub fn add_asset_metadata(
+        &mut self,
+        asset_id: AssetId,
+        asset_meta: &AssetMetadata,
+    ) -> Option<Result<AssetMetadata, encode::Error>> {
+        let key = prop_key(&asset_id);
+        self.global
+            .proprietary
+            .insert(key, asset_meta.serialize())
+            .map(|old| AssetMetadata::deserialize(&old))
+    }
+
+    /// Get contract information from the PSET, returns None if there are no information regarding
+    /// the given `asset_id`` in the PSET
+    pub fn get_asset_metadata(
+        &self,
+        asset_id: AssetId,
+    ) -> Option<Result<AssetMetadata, encode::Error>> {
+        let key = prop_key(&asset_id);
+
+        self.global
+            .proprietary
+            .get(&key)
+            .map(|data| AssetMetadata::deserialize(data))
+    }
+}
+
+/// Asset metadata, the contract and the outpoint used to issue the asset
+#[derive(Debug, PartialEq, Eq)]
+pub struct AssetMetadata {
+    contract: String,
+    issuance_prevout: OutPoint,
+}
+
+fn prop_key(asset_id: &AssetId) -> ProprietaryKey {
+    let mut key = Vec::with_capacity(32);
+    asset_id
+        .consensus_encode(&mut key)
+        .expect("vec doesn't err"); // equivalent to asset_tag
+
+    ProprietaryKey {
+        prefix: PSET_HWW_PREFIX.to_vec(),
+        subtype: 0x00,
+        key,
+    }
+}
+
+impl AssetMetadata {
+    /// Returns the contract as string containing a json
+    pub fn contract(&self) -> &str {
+        &self.contract
+    }
+
+    /// Returns the issuance prevout where the asset has been issued
+    pub fn issuance_prevout(&self) -> OutPoint {
+        self.issuance_prevout
+    }
+
+    /// Serialize this metadata as defined by ELIP0100
+    ///
+    /// `<compact size uint contractLen><contract><32-byte prevoutTxid><32-bit little endian uint prevoutIndex>`
+    pub fn serialize(&self) -> Vec<u8> {
+        let mut result = vec![];
+
+        encode::consensus_encode_with_size(self.contract.as_bytes(), &mut result)
+            .expect("vec doesn't err");
+
+        self.issuance_prevout
+            .consensus_encode(&mut result)
+            .expect("vec doesn't err");
+
+        result
+    }
+
+    /// Deserialize this metadata as defined by ELIP0100
+    pub fn deserialize(data: &[u8]) -> Result<AssetMetadata, encode::Error> {
+        let mut cursor = Cursor::new(data);
+        let str_bytes = Vec::<u8>::consensus_decode(&mut cursor)?;
+
+        let contract = String::from_utf8(str_bytes).map_err(|_| {
+            encode::Error::ParseFailed("utf8 conversion fail on the contract string")
+        })?;
+
+        let issuance_prevout = OutPoint::consensus_decode(&mut cursor)?;
+
+        Ok(AssetMetadata {
+            contract,
+            issuance_prevout,
+        })
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use std::str::FromStr;
+
+    use crate::encode::serialize;
+    use crate::{OutPoint, Txid};
+    use bitcoin::hashes::hex::FromHex;
+    use bitcoin::hashes::Hash;
+
+    use crate::{
+        encode::{serialize_hex, Encodable},
+        hex::ToHex,
+        pset::{elip100::PSET_HWW_PREFIX, map::Map, PartiallySignedTransaction},
+        AssetId,
+    };
+
+    use super::{prop_key, AssetMetadata};
+
+    #[cfg(feature = "json-contract")]
+    const CONTRACT_HASH: &str = "3c7f0a53c2ff5b99590620d7f6604a7a3a7bfbaaa6aa61f7bfc7833ca03cde82";
+
+    const VALID_CONTRACT: &str = r#"{"entity":{"domain":"tether.to"},"issuer_pubkey":"0337cceec0beea0232ebe14cba0197a9fbd45fcf2ec946749de920e71434c2b904","name":"Tether USD","precision":8,"ticker":"USDt","version":0}"#;
+    const ISSUANCE_PREVOUT: &str =
+        "9596d259270ef5bac0020435e6d859aea633409483ba64e232b8ba04ce288668:0";
+    const ASSET_ID: &str = "ce091c998b83c78bb71a632313ba3760f1763d9cfcffae02258ffa9865a37bd2";
+
+    const ELIP0100_IDENTIFIER: &str = "fc08707365745f68777700";
+    const ELIP0100_ASSET_TAG: &str =
+        "48f835622f34e8fdc313c90d4a8659aa4afe993e32dcb03ae6ec9ccdc6fcbe18";
+
+    const ELIP0100_CONTRACT: &str = r#"{"entity":{"domain":"example.com"},"issuer_pubkey":"03455ee7cedc97b0ba435b80066fc92c963a34c600317981d135330c4ee43ac7a3","name":"Testcoin","precision":2,"ticker":"TEST","version":0}"#;
+    const ELIP0100_PREVOUT_TXID: &str =
+        "3514a07cf4812272c24a898c482f587a51126beef8c9b76a9e30bf41b0cbe53c";
+
+    const ELIP0100_PREVOUT_VOUT: u32 = 1;
+    const ELIP0100_ASSET_METADATA_RECORD_KEY: &str =
+        "fc08707365745f6877770018befcc6cd9cece63ab0dc323e99fe4aaa59864a0dc913c3fde8342f6235f848";
+    const ELIP0100_ASSET_METADATA_RECORD_VALUE_WRONG: &str = "b47b22656e74697479223a7b22646f6d61696e223a226578616d706c652e636f6d227d2c226973737565725f7075626b6579223a22303334353565653763656463393762306261343335623830303636666339326339363361333463363030333137393831643133353333306334656534336163376133222c226e616d65223a2254657374636f696e222c22707265636973696f6e223a322c227469636b6572223a2254455354222c2276657273696f6e223a307d3514a07cf4812272c24a898c482f587a51126beef8c9b76a9e30bf41b0cbe53c01000000";
+
+    const ELIP0100_ASSET_METADATA_RECORD_VALUE: &str = "b47b22656e74697479223a7b22646f6d61696e223a226578616d706c652e636f6d227d2c226973737565725f7075626b6579223a22303334353565653763656463393762306261343335623830303636666339326339363361333463363030333137393831643133353333306334656534336163376133222c226e616d65223a2254657374636f696e222c22707265636973696f6e223a322c227469636b6572223a2254455354222c2276657273696f6e223a307d3ce5cbb041bf309e6ab7c9f8ee6b12517a582f488c894ac2722281f47ca0143501000000";
+    fn mockup_asset_metadata() -> (AssetId, AssetMetadata) {
+        (
+            AssetId::from_str(ASSET_ID).unwrap(),
+            AssetMetadata {
+                contract: VALID_CONTRACT.to_string(),
+                issuance_prevout: ISSUANCE_PREVOUT.parse().unwrap(),
+            },
+        )
+    }
+
+    #[cfg(feature = "json-contract")]
+    #[test]
+    fn asset_metadata_roundtrip() {
+        let (_, asset_metadata) = mockup_asset_metadata();
+        let contract_hash = crate::ContractHash::from_str(CONTRACT_HASH).unwrap();
+        assert_eq!(
+            crate::ContractHash::from_json_contract(VALID_CONTRACT).unwrap(),
+            contract_hash
+        );
+        assert_eq!(asset_metadata.serialize().to_hex(),"b47b22656e74697479223a7b22646f6d61696e223a227465746865722e746f227d2c226973737565725f7075626b6579223a22303333376363656563306265656130323332656265313463626130313937613966626434356663663265633934363734396465393230653731343334633262393034222c226e616d65223a2254657468657220555344222c22707265636973696f6e223a382c227469636b6572223a2255534474222c2276657273696f6e223a307d688628ce04bab832e264ba83944033a6ae59d8e6350402c0baf50e2759d2969500000000");
+
+        assert_eq!(
+            AssetMetadata::deserialize(&asset_metadata.serialize()).unwrap(),
+            asset_metadata
+        );
+    }
+
+    #[test]
+    fn prop_key_serialize() {
+        let asset_id = AssetId::from_str(ASSET_ID).unwrap();
+
+        let key = prop_key(&asset_id);
+        let mut vec = vec![];
+        key.consensus_encode(&mut vec).unwrap();
+
+        assert_eq!(
+            vec.to_hex(),
+            format!("08{}00{}", PSET_HWW_PREFIX.to_hex(), asset_id.into_tag())
+        );
+
+        assert!(vec.to_hex().starts_with(&ELIP0100_IDENTIFIER[2..])); // cut prefix "fc: which is PSET_GLOBAL_PROPRIETARY serialized one level up
+    }
+
+    #[test]
+    fn set_get_asset_metadata() {
+        let mut pset = PartiallySignedTransaction::new_v2();
+        let (asset_id, asset_meta) = mockup_asset_metadata();
+
+        let old = pset.add_asset_metadata(asset_id, &asset_meta);
+        assert!(old.is_none());
+        let old = pset
+            .add_asset_metadata(asset_id, &asset_meta)
+            .unwrap()
+            .unwrap();
+        assert_eq!(old, asset_meta);
+
+        assert!(serialize_hex(&pset).contains(ELIP0100_IDENTIFIER));
+
+        let get = pset.get_asset_metadata(asset_id).unwrap().unwrap();
+        assert_eq!(get, asset_meta);
+    }
+
+    #[test]
+    fn elip0100_test_vector() {
+        let mut pset = PartiallySignedTransaction::new_v2();
+
+        let asset_id = AssetId::from_str(ELIP0100_ASSET_TAG).unwrap();
+        let txid = Txid::from_str(ELIP0100_PREVOUT_TXID).unwrap();
+
+        let asset_meta = AssetMetadata {
+            contract: ELIP0100_CONTRACT.to_string(),
+            issuance_prevout: OutPoint {
+                txid,
+                vout: ELIP0100_PREVOUT_VOUT,
+            },
+        };
+
+        pset.add_asset_metadata(asset_id, &asset_meta);
+
+        let expected_key = Vec::<u8>::from_hex(ELIP0100_ASSET_METADATA_RECORD_KEY).unwrap();
+
+        let values: Vec<Vec<u8>> = pset
+            .global
+            .get_pairs()
+            .unwrap()
+            .into_iter()
+            .filter(|p| serialize(&p.key)[1..] == expected_key[..]) // NOTE key serialization contains an initial varint with the lenght of the key which is not present in the test vector
+            .map(|p| p.value)
+            .collect();
+        assert_eq!(values.len(), 1);
+        assert_eq!(values[0].to_hex(), ELIP0100_ASSET_METADATA_RECORD_VALUE);
+
+        let txid_hex_non_convention = txid.as_byte_array().to_vec().to_hex();
+        assert_eq!(
+            ELIP0100_ASSET_METADATA_RECORD_VALUE,
+            ELIP0100_ASSET_METADATA_RECORD_VALUE_WRONG
+                .replace(ELIP0100_PREVOUT_TXID, &txid_hex_non_convention),
+            "only change in the value is the txid"
+        );
+    }
+
+    #[cfg(feature = "json-contract")]
+    #[test]
+    fn elip0100_contract() {
+        let txid = Txid::from_str(ELIP0100_PREVOUT_TXID).unwrap();
+        let prevout = OutPoint {
+            txid,
+            vout: ELIP0100_PREVOUT_VOUT,
+        };
+
+        let contract_hash = crate::ContractHash::from_json_contract(ELIP0100_CONTRACT).unwrap();
+        let entropy = AssetId::generate_asset_entropy(prevout, contract_hash);
+        let asset_id = AssetId::from_entropy(entropy);
+
+        let expected = AssetId::from_str(ELIP0100_ASSET_TAG).unwrap();
+
+        assert_eq!(asset_id.to_hex(), expected.to_hex());
+    }
+}

src/pset/mod.rs

@@ -29,6 +29,7 @@ mod macros;
 mod map;
 pub mod raw;
 pub mod serialize;
+pub mod elip100;
 
 #[cfg(feature = "base64")]
 mod str;