breez_sdk_liquid/payjoin/pset/
mod.rs

1pub(crate) mod blind;
2mod tests;
3
4use anyhow::{anyhow, ensure, Result};
5use bip39::rand;
6use lwk_wollet::bitcoin;
7use lwk_wollet::elements::confidential::{Asset, Value};
8use lwk_wollet::elements::pset::{Input, Output, PartiallySignedTransaction};
9use lwk_wollet::elements::script::Script;
10use lwk_wollet::elements::{self, AssetId, OutPoint, TxOut, TxOutSecrets, Txid};
11use rand::seq::SliceRandom;
12
13pub struct PsetInput {
14    pub txid: Txid,
15    pub vout: u32,
16    pub script_pub_key: Script,
17    pub asset_commitment: Asset,
18    pub value_commitment: Value,
19    pub tx_out_sec: TxOutSecrets,
20}
21
22pub struct PsetOutput {
23    pub address: elements::Address,
24    pub asset_id: AssetId,
25    pub amount: u64,
26}
27
28pub struct ConstructPsetRequest {
29    pub policy_asset: AssetId,
30    pub inputs: Vec<PsetInput>,
31    pub outputs: Vec<PsetOutput>,
32    pub network_fee: u64,
33}
34
35fn pset_input(input: PsetInput) -> Input {
36    let PsetInput {
37        txid,
38        vout,
39        script_pub_key,
40        asset_commitment,
41        value_commitment,
42        tx_out_sec: _,
43    } = input;
44
45    let mut pset_input = Input::from_prevout(OutPoint { txid, vout });
46
47    pset_input.witness_utxo = Some(TxOut {
48        asset: asset_commitment,
49        value: value_commitment,
50        nonce: elements::confidential::Nonce::Null,
51        script_pubkey: script_pub_key,
52        witness: elements::TxOutWitness::default(),
53    });
54
55    pset_input
56}
57
58fn pset_output(output: PsetOutput) -> Result<Output> {
59    let PsetOutput {
60        address,
61        asset_id,
62        amount,
63    } = output;
64
65    let blinding_pubkey = address
66        .blinding_pubkey
67        .ok_or_else(|| anyhow!("only blinded addresses allowed"))?;
68    ensure!(amount > 0);
69
70    let txout = TxOut {
71        asset: Asset::Explicit(asset_id),
72        value: Value::Explicit(amount),
73        nonce: elements::confidential::Nonce::Confidential(blinding_pubkey),
74        script_pubkey: address.script_pubkey(),
75        witness: elements::TxOutWitness::default(),
76    };
77
78    let mut output = Output::from_txout(txout);
79
80    output.blinding_key = Some(bitcoin::PublicKey::new(blinding_pubkey));
81    output.blinder_index = Some(0);
82
83    Ok(output)
84}
85
86fn pset_network_fee(asset: AssetId, amount: u64) -> Output {
87    let network_fee_output = TxOut::new_fee(amount, asset);
88    Output::from_txout(network_fee_output)
89}
90
91pub fn construct_pset(req: ConstructPsetRequest) -> Result<PartiallySignedTransaction> {
92    let ConstructPsetRequest {
93        policy_asset,
94        mut inputs,
95        mut outputs,
96        network_fee,
97    } = req;
98
99    let mut pset = PartiallySignedTransaction::new_v2();
100    let mut input_secrets = Vec::new();
101    let blinding_factors = Vec::new();
102
103    let mut rng = rand::thread_rng();
104    inputs.shuffle(&mut rng);
105    outputs.shuffle(&mut rng);
106
107    for input in inputs.into_iter() {
108        input_secrets.push(input.tx_out_sec);
109
110        pset.add_input(pset_input(input));
111    }
112
113    for output in outputs {
114        pset.add_output(pset_output(output)?);
115    }
116
117    pset.add_output(pset_network_fee(policy_asset, network_fee));
118
119    blind::blind_pset(&mut pset, &input_secrets, &blinding_factors)?;
120    Ok(pset)
121}
breez_sdk_liquid/payjoin/pset/mod.rs

breez_sdk_liquid/payjoin/pset/
mod.rs
