From 3d67bf23b0c1ea265bae4e23ad083022f8eb4a35 Mon Sep 17 00:00:00 2001
From: sekulicd <sekula87@gmail.com>
Date: Wed, 20 May 2020 13:41:54 +0200
Subject: [PATCH 1/2] added factory method FromPublicKeys for creating
 multiscript payment

---
 payment/payment.go      | 36 +++++++++++++++++++++++++++++++++++-
 payment/payment_test.go | 29 ++++++++++++++++++++++++-----
 2 files changed, 59 insertions(+), 6 deletions(-)

diff --git a/payment/payment.go b/payment/payment.go
index 6fe6fe1..5ae1450 100644
--- a/payment/payment.go
+++ b/payment/payment.go
@@ -3,7 +3,9 @@ package payment
 import (
 	"crypto/sha256"
 	"errors"
+	"fmt"
 	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/txscript"
 	"github.com/vulpemventures/go-elements/address"
 	"github.com/vulpemventures/go-elements/network"
 	"golang.org/x/crypto/ripemd160"
@@ -11,7 +13,8 @@ import (
 )
 
 const (
-	Op0 = 0x00
+	Op0             = 0x00 // 0
+	OpCheckMultiSig = 0xae // 174
 )
 
 // Payment defines the structure that holds the information different addresses
@@ -45,6 +48,37 @@ func FromPublicKey(pubkey *btcec.PublicKey, net *network.Network) *Payment {
 	return &Payment{tmpNet, pubkey, pkHash, nil, nil, script, witnessHash[:]}
 }
 
+// FromPublicKeys creates a multi-signature Payment struct from list of public key's
+func FromPublicKeys(pubkeys []*btcec.PublicKey, numOfPksRequired int, net *network.Network) (*Payment, error) {
+	if len(pubkeys) < numOfPksRequired {
+		errorMsg := fmt.Sprintf("unable to generate multisig script with "+
+			"%d required signatures when there are only %d public "+
+			"keys available", numOfPksRequired, len(pubkeys))
+		return nil, errors.New(errorMsg)
+	}
+
+	var tmpNet *network.Network
+	if net == nil {
+		tmpNet = &network.Liquid
+	} else {
+		tmpNet = net
+	}
+
+	builder := txscript.NewScriptBuilder().AddInt64(int64(numOfPksRequired))
+	for _, key := range pubkeys {
+		builder.AddData(key.SerializeCompressed())
+	}
+	builder.AddInt64(int64(len(pubkeys)))
+	builder.AddOp(OpCheckMultiSig)
+
+	multiSigScript, err := builder.Script()
+	if err != nil {
+		return nil, err
+	}
+
+	return FromScript(multiSigScript, tmpNet)
+}
+
 // FromPayment creates a Payment struct from a another Payment
 func FromPayment(payment *Payment) (*Payment, error) {
 	if payment.Script == nil || len(payment.Script) == 0 {
diff --git a/payment/payment_test.go b/payment/payment_test.go
index 9457343..702ff41 100644
--- a/payment/payment_test.go
+++ b/payment/payment_test.go
@@ -8,12 +8,16 @@ import (
 	"testing"
 )
 
-const privKeyHex = "1cc080a4cd371eafcad489a29664af6a7276b362fe783443ce036552482b971d"
+const (
+	privKeyHex1 = "1cc080a4cd371eafcad489a29664af6a7276b362fe783443ce036552482b971d"
+	privKeyHex2 = "4d6718d4a02f774e752faa97e2c3b70db6b9d9ed5bd2fcecb093bd650f449a51"
+)
 
-var privateKeyBytes, _ = hex.DecodeString(privKeyHex)
+var privateKeyBytes1, _ = hex.DecodeString(privKeyHex1)
+var privateKeyBytes2, _ = hex.DecodeString(privKeyHex2)
 
 func TestLegacyAddress(t *testing.T) {
-	_, publicKey := btcec.PrivKeyFromBytes(btcec.S256(), privateKeyBytes)
+	_, publicKey := btcec.PrivKeyFromBytes(btcec.S256(), privateKeyBytes1)
 
 	pay := payment.FromPublicKey(publicKey, &network.Regtest)
 	if pay.PubKeyHash() != "2dxEMfPLNa6rZRAfPe7wNWoaUptyBzQ2Zva" {
@@ -22,7 +26,7 @@ func TestLegacyAddress(t *testing.T) {
 }
 
 func TestSegwitAddress(t *testing.T) {
-	_, publicKey := btcec.PrivKeyFromBytes(btcec.S256(), privateKeyBytes)
+	_, publicKey := btcec.PrivKeyFromBytes(btcec.S256(), privateKeyBytes1)
 
 	pay := payment.FromPublicKey(publicKey, &network.Regtest)
 	p2pkh, err := pay.WitnessPubKeyHash()
@@ -35,7 +39,7 @@ func TestSegwitAddress(t *testing.T) {
 }
 
 func TestScriptHash(t *testing.T) {
-	_, publicKey := btcec.PrivKeyFromBytes(btcec.S256(), privateKeyBytes)
+	_, publicKey := btcec.PrivKeyFromBytes(btcec.S256(), privateKeyBytes1)
 	p2wpkh := payment.FromPublicKey(publicKey, &network.Regtest)
 	pay, err := payment.FromPayment(p2wpkh)
 	p2sh, err := pay.ScriptHash()
@@ -72,3 +76,18 @@ func TestP2WSH(t *testing.T) {
 		t.Errorf("TestSegwitAddress: error when encoding segwit")
 	}
 }
+
+func TestFromPublicKeys(t *testing.T) {
+	_, publicKey1 := btcec.PrivKeyFromBytes(btcec.S256(), privateKeyBytes1)
+	_, publicKey2 := btcec.PrivKeyFromBytes(btcec.S256(), privateKeyBytes2)
+
+	p2ms, err := payment.FromPublicKeys([]*btcec.PublicKey{publicKey1, publicKey2}, 1, &network.Regtest)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if hex.EncodeToString(p2ms.Script) != "5121036f5646ed688b9279369da0a4ad78953ae7e6d300436ca8a3264360efe38236e321023c61f59e9a3a3eb01c3ed0cf967ad217153944bcf2498a8fd6e70b27c7ab6ee652ae" {
+		t.Error("hax value of p2ms script not as expected")
+	}
+
+}

From 056037a5a82ca83357f1f1c3f1e9af12a19166a4 Mon Sep 17 00:00:00 2001
From: sekulicd <sekula87@gmail.com>
Date: Wed, 26 Oct 2022 17:27:07 +0200
Subject: [PATCH 2/2] blinding bug

---
 psetv2/blinder.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/psetv2/blinder.go b/psetv2/blinder.go
index ecb7fc3..70c65c4 100644
--- a/psetv2/blinder.go
+++ b/psetv2/blinder.go
@@ -443,7 +443,11 @@ func (b *Blinder) blind(
 	}
 
 	if !isLastBlinder {
-		p.Global.Scalars = append(b.Pset.Global.Scalars, outputScalar)
+		outScalar, err := b.generator.SubtractScalars(outputScalar, inputScalar)
+		if err != nil {
+			return err
+		}
+		p.Global.Scalars = append(b.Pset.Global.Scalars, outScalar)
 	} else {
 		p.Global.Scalars = nil
 	}