New address encoding (#356)

* [common] rework address encoding

* new address encoding

* replace offchain address by vtxo output key in DB

* merge migrations files into init one

* fix txbuilder fixtures

* fix transaction events

common/encoding.go

@@ -3,63 +3,68 @@ package common
 import (
 	"fmt"
 
+	"github.com/btcsuite/btcd/btcec/v2/schnorr"
 	"github.com/btcsuite/btcd/btcutil/bech32"
 	"github.com/decred/dcrd/dcrec/secp256k1/v4"
 )
 
-func EncodeAddress(
-	hrp string, userKey, aspKey *secp256k1.PublicKey,
-) (addr string, err error) {
-	if userKey == nil {
-		err = fmt.Errorf("missing public key")
-		return
+// Address represents an Ark address with HRP, ASP public key, and VTXO Taproot public key
+type Address struct {
+	HRP        string
+	Asp        *secp256k1.PublicKey
+	VtxoTapKey *secp256k1.PublicKey
+}
+
+// Encode converts the address to its bech32m string representation
+func (a *Address) Encode() (string, error) {
+	if a.Asp == nil {
+		return "", fmt.Errorf("missing asp public key")
 	}
-	if aspKey == nil {
-		err = fmt.Errorf("missing asp public key")
-		return
-	}
-	if hrp != Liquid.Addr && hrp != LiquidTestNet.Addr {
-		err = fmt.Errorf("invalid prefix")
-		return
+	if a.VtxoTapKey == nil {
+		return "", fmt.Errorf("missing vtxo tap public key")
 	}
+
 	combinedKey := append(
-		aspKey.SerializeCompressed(), userKey.SerializeCompressed()...,
+		schnorr.SerializePubKey(a.Asp), schnorr.SerializePubKey(a.VtxoTapKey)...,
 	)
 	grp, err := bech32.ConvertBits(combinedKey, 8, 5, true)
 	if err != nil {
-		return
+		return "", err
 	}
-	addr, err = bech32.EncodeM(hrp, grp)
-	return
+	return bech32.EncodeM(a.HRP, grp)
 }
 
-func DecodeAddress(
-	addr string,
-) (hrp string, userKey, aspKey *secp256k1.PublicKey, err error) {
+// DecodeAddress parses a bech32m encoded address string and returns an Address object
+func DecodeAddress(addr string) (*Address, error) {
+	if len(addr) == 0 {
+		return nil, fmt.Errorf("address is empty")
+	}
+
 	prefix, buf, err := bech32.DecodeNoLimit(addr)
 	if err != nil {
-		return
+		return nil, err
 	}
 	if prefix != Liquid.Addr && prefix != LiquidTestNet.Addr && prefix != LiquidRegTest.Addr {
-		err = fmt.Errorf("invalid prefix")
-		return
+		return nil, fmt.Errorf("invalid prefix")
 	}
 	grp, err := bech32.ConvertBits(buf, 5, 8, false)
 	if err != nil {
-		return
+		return nil, err
 	}
-	aKey, err := secp256k1.ParsePubKey(grp[:33])
+
+	aKey, err := schnorr.ParsePubKey(grp[:32])
 	if err != nil {
-		err = fmt.Errorf("failed to parse public key: %s", err)
-		return
+		return nil, fmt.Errorf("failed to parse public key: %s", err)
 	}
-	uKey, err := secp256k1.ParsePubKey(grp[33:])
+
+	vtxoKey, err := schnorr.ParsePubKey(grp[32:])
 	if err != nil {
-		err = fmt.Errorf("failed to parse asp public key: %s", err)
-		return
+		return nil, fmt.Errorf("failed to parse asp public key: %s", err)
 	}
-	hrp = prefix
-	userKey = uKey
-	aspKey = aKey
-	return
+
+	return &Address{
+		HRP:        prefix,
+		Asp:        aKey,
+		VtxoTapKey: vtxoKey,
+	}, nil
 }