Merge #143: Blinding API cleanups

582325e rustfmt: add src/pset/mod.rs and src/blind.rs (sanket1729)
759d301 Add liquid testnet parameters (sanket1729)
2908bc1 Allow inserting inputs/outputs at specified positions (sanket1729)
cbc2d56 Add issuance surjection proof verification (sanket1729)
3583ae2 Fix pset key bug (sanket1729)
2815e52 Fix pset Tweak serde (sanket1729)
3107c25 Add support for issuance (sanket1729)
fa753b4 Cleanup bunch of blinding APIs (sanket1729)
d521aee Remove public has_issuance field from TxIn (sanket1729)

Pull request description:

  - This required the user to explicitly maintain whether the current TxIn
  has issuance or not whereas it can directly be calculated from
  assetIssuance field

  The blinding APIs are separated into smaller chunks. This allows
      - Blinding only the values or the assets but not both
      - Not relying on rng to set asset/value blinding factors
      - Better input parameters

  Note I had to edit the test vectors the order in which they were sampled from rng had changed.

ACKs for top commit:
  apoelstra:
    ACK 582325e

Tree-SHA512: 1d70b58bc136341d1933a872749982cac8507aa5f355774de2dcaecfe68f89926d938bdf24031e8e34782562c5c78bb10d00d5726a2113c5dea1ee139bb2de0e

Author: apoelstra

examples/pset_blind_coinjoin.rs

@@ -266,20 +266,16 @@ fn main() {
     // ----------------------------------------------------------
     // B Adds it's own outputs. Step 2 completed
     // ----- Step 3: B to blind it's own outputs
-    let inp_txout_sec = [
-        None,
-        Some(&asset_txout_secrets.sec),
-    ];
+    let mut inp_txout_sec = HashMap::new();
+    inp_txout_sec.insert(1, asset_txout_secrets.sec);
 
     pset.blind_non_last(&mut rng, &secp, &inp_txout_sec).unwrap();
     assert_eq!(pset, deser_pset(&tests["pset_coinjoined_B_blinded"]));
 
     // Step 4: A blinds it's own inputs
-    let inp_txout_sec = [
-        Some(&btc_txout_secrets.sec),
-        None,
-    ];
-    pset.blind_last(&mut rng, &secp, &inp_txout_sec).unwrap();
+    let mut inp_txout_sec_a = HashMap::new();
+    inp_txout_sec_a.insert(0, btc_txout_secrets.sec);
+    pset.blind_last(&mut rng, &secp, &inp_txout_sec_a).unwrap();
     assert_eq!(pset, deser_pset(&tests["pset_coinjoined_blinded"]));
 
     // check whether the blinding was correct

examples/raw_blind.rs

@@ -10,7 +10,7 @@ use elements::{
     bitcoin::PublicKey, pset::PartiallySignedTransaction as Pset, Address, AddressParams, OutPoint,
     Script, TxOutSecrets, TxOutWitness, Txid, WScriptHash,
 };
-use elements::{pset, secp256k1_zkp};
+use elements::{pset, secp256k1_zkp, SurjectionInput};
 
 use elements::encode::{deserialize, serialize_hex};
 use elements::hashes::hex::FromHex;
@@ -168,8 +168,8 @@ fn main() {
     // Add outputs
     // Send 5_000 worth of asset units to new address
     let inputs = [
-        (btc_txout.asset, Some(&btc_txout_secrets.sec)),
-        (asset_txout.asset, Some(&asset_txout_secrets.sec)),
+        (SurjectionInput::from_txout_secrets(btc_txout_secrets.sec)),
+        (SurjectionInput::from_txout_secrets(asset_txout_secrets.sec)),
     ];
 
     let dest_wsh =
@@ -179,7 +179,7 @@ fn main() {
     let dest_blind_pk =
         PublicKey::from_str("0212bf0ea45b733dfde8ecb5e896306c4165c666c99fc5d1ab887f71393a975cea")
             .unwrap();
-    let (dest_asset_txout, dest_abf, dest_vbf) = TxOut::new_not_last_confidential(
+    let (dest_asset_txout, dest_abf, dest_vbf, _) = TxOut::new_not_last_confidential(
         &mut rng,
         &secp,
         dest_amt,
@@ -200,7 +200,7 @@ fn main() {
     let change_wsh =
         WScriptHash::from_str("f6b43d56e004e9d0b1ec2fc3c95511d81af08420992be8dec7f86cdf8970b3e2")
             .unwrap();
-    let (change_asset_txout, asset_change_abf, asset_change_vbf) =
+    let (change_asset_txout, asset_change_abf, asset_change_vbf, _) =
         TxOut::new_not_last_confidential(
             &mut rng,
             &secp,
@@ -254,19 +254,16 @@ fn main() {
 
     // For the last output we require all secrets.
     let inputs = [
-        (btc_txout.asset, &btc_txout_secrets.sec),
-        (asset_txout.asset, &asset_txout_secrets.sec),
+        btc_txout_secrets.sec,
+        asset_txout_secrets.sec,
     ];
-    let (btc_change_txout, _abf, _vbf) = TxOut::new_last_confidential(
+    let (btc_change_txout, _abf, _vbf, _) = TxOut::new_last_confidential(
         &mut rng,
         &secp,
         change_amt,
-        Address::p2wsh(
-            &Script::new_v0_wsh(&change_wsh),
-            Some(change_blind_pk.inner),
-            &PARAMS,
-        ),
         btc_txout_secrets.sec.asset,
+        Script::new_v0_wsh(&change_wsh),
+        change_blind_pk.inner,
         &inputs,
         &output_secrets,
     )

examples/test_vector/pset_blind_coinjoin/pset_coinjoined_B_blinded.hex

@@ -146,6 +146,15 @@ impl AddressParams {
         bech_hrp: "ert",
         blech_hrp: "el",
     };
+
+    /// The default liquid testnet network address parameters.
+    pub const LIQUID_TESTNET: AddressParams = AddressParams {
+        p2pkh_prefix: 36,
+        p2sh_prefix: 19,
+        blinded_prefix: 23,
+        bech_hrp: "tex",
+        blech_hrp: "tlq",
+    };
 }
 
 /// The method used to produce an address
@@ -439,7 +448,7 @@ impl Address {
         if data.len() < 2 || data.len() > 40 + if blinded { 33 } else { 0 } {
             return Err(AddressError::InvalidWitnessProgramLength(data.len() - if blinded { 33 } else { 0 }));
         }
- 
+
         // Specific segwit v0 check.
         if !blinded && version.to_u8() == 0 && data.len() != 20 && data.len() != 32 {
             return Err(AddressError::InvalidSegwitV0ProgramLength(data.len()));
@@ -649,20 +658,19 @@ impl FromStr for Address {
         // shorthands
         let liq = &AddressParams::LIQUID;
         let ele = &AddressParams::ELEMENTS;
+        let liq_test = &AddressParams::LIQUID_TESTNET;
+
+        let net_arr = [liq, ele, liq_test];
 
-        // Bech32.
         let prefix = find_prefix(s);
-        if match_prefix(prefix, liq.bech_hrp) {
-            return Address::from_bech32(s, false, liq);
-        }
-        if match_prefix(prefix, liq.blech_hrp) {
-            return Address::from_bech32(s, true, liq);
-        }
-        if match_prefix(prefix, ele.bech_hrp) {
-            return Address::from_bech32(s, false, ele);
-        }
-        if match_prefix(prefix, ele.blech_hrp) {
-            return Address::from_bech32(s, true, ele);
+        for net in net_arr.iter() {
+            // Bech32.
+            if match_prefix(prefix, net.bech_hrp) {
+                return Address::from_bech32(s, false, net);
+            }
+            if match_prefix(prefix, net.blech_hrp) {
+                return Address::from_bech32(s, true, net);
+            }
         }
 
         // Base58.
@@ -675,11 +683,10 @@ impl FromStr for Address {
         }
 
         let p = data[0];
-        if p == liq.p2pkh_prefix || p == liq.p2sh_prefix || p == liq.blinded_prefix {
-            return Address::from_base58(&data, liq);
-        }
-        if p == ele.p2pkh_prefix || p == ele.p2sh_prefix || p == ele.blinded_prefix {
-            return Address::from_base58(&data, ele);
+        for net in net_arr.iter() {
+            if p == net.p2pkh_prefix || p == net.p2sh_prefix || p == net.blinded_prefix {
+                return Address::from_base58(&data, net);
+            }
         }
 
         Err(AddressError::InvalidAddress(s.to_owned()))