Coin swap proof

.gitignore

@@ -1,6 +1,7 @@
 *.prof
 *.test
 dist
+.vscode
 
 # binaries
 synapsebeacon

go.sum

@@ -28,6 +28,7 @@ github.com/btcsuite/btcd v0.0.0-20190523000118-16327141da8c/go.mod h1:3J08xEfcug
 github.com/btcsuite/btcd v0.0.0-20190614013741-962a206e94e9 h1:18Pe+JPyglNO9lzLrQHj7Dwmdi4c49D8xQTqTRz3qJo=
 github.com/btcsuite/btcd v0.0.0-20190614013741-962a206e94e9/go.mod h1:3J08xEfcugPacsc34/LKRU2yO7YmuT8yt28J8k2+rrI=
 github.com/btcsuite/btclog v0.0.0-20170628155309-84c8d2346e9f/go.mod h1:TdznJufoqS23FtqVCzL0ZqgP5MqXbb4fg/WgDys70nA=
+github.com/btcsuite/btcutil v0.0.0-20190207003914-4c204d697803 h1:j3AgPKKZtZStM2nyhrDSLSYgT7YHrZKdSkq1OYeLjvM=
 github.com/btcsuite/btcutil v0.0.0-20190207003914-4c204d697803/go.mod h1:+5NJ2+qvTyV9exUAL/rxXi3DcLg2Ts+ymUAY5y4NvMg=
 github.com/btcsuite/btcutil v0.0.0-20190425235716-9e5f4b9a998d/go.mod h1:+5NJ2+qvTyV9exUAL/rxXi3DcLg2Ts+ymUAY5y4NvMg=
 github.com/btcsuite/go-socks v0.0.0-20170105172521-4720035b7bfd/go.mod h1:HHNXQzUsZCxOoE+CPiyCTO6x34Zs86zZUiwtpXoGdtg=

swap/coinswap.go

@@ -0,0 +1,122 @@
+package swap
+
+// This file is for swapping coins from Phore to Synapse
+
+import (
+	"encoding/hex"
+	"encoding/json"
+
+	"github.com/phoreproject/synapse/chainhash"
+	"github.com/btcsuite/btcd/txscript"
+	"github.com/btcsuite/btcd/wire"
+	btcdhash "github.com/btcsuite/btcd/chaincfg/chainhash"
+)
+
+type proofEntry struct {
+	left bool
+	hash *chainhash.Hash
+}
+
+func computeCombinedHash(left *chainhash.Hash, right *chainhash.Hash) chainhash.Hash {
+	h := chainhash.HashH(chainhash.HashB(append(left[:], right[:]...)))
+	return h
+}
+
+func computeProofRootHash(hash *chainhash.Hash, entries []proofEntry) chainhash.Hash {
+	h := *hash
+	for i := 0; i < len(entries); i++ {
+		if entries[i].left {
+			h = computeCombinedHash(entries[i].hash, &h)
+		} else {
+			h = computeCombinedHash(&h, entries[i].hash)
+		}
+	}
+	return h
+}
+
+type jsonProofEntry struct {
+	Left int    `json:"left"`
+	Hash string `json:"hash"`
+}
+
+// The text is generated by SynapseSwap::proofListToText in C++
+func textToProofList(text string) []proofEntry {
+	entries := &[]*jsonProofEntry{}
+	err := json.Unmarshal([]byte(text), entries)
+	if err != nil {
+		panic(err)
+	}
+	proofList := []proofEntry{}
+	for _, e := range *entries {
+		h, _ := chainhash.NewHashFromStr(e.Hash)
+		proofList = append(proofList, proofEntry{
+			left: e.Left != 0,
+			hash: h,
+		})
+	}
+	return proofList
+}
+
+type unlockItem struct {
+	txid         chainhash.Hash
+	out          int
+	scriptPubKey []byte
+	amount       int64
+	redeemScript []byte
+}
+
+type jsonUnlockItem struct {
+	Txid         string `json:"txid"`
+	Out          int    `json:"out"`
+	ScriptPubKey string `json:"scriptPubKey"`
+	Amount       int64  `json:"amount"`
+	RedeemScript string `json:"redeemScript"`
+}
+
+func textToUnlockItem(text string) unlockItem {
+	jsonItem := &jsonUnlockItem{}
+	err := json.Unmarshal([]byte(text), jsonItem)
+	if err != nil {
+		panic(err)
+	}
+
+	txid, _ := chainhash.NewHashFromStr(jsonItem.Txid)
+	scriptPubKey, _ := hex.DecodeString(jsonItem.ScriptPubKey)
+	redeemScript, _ := hex.DecodeString(jsonItem.RedeemScript)
+	item := unlockItem{
+		txid:         *txid,
+		out:          jsonItem.Out,
+		scriptPubKey: scriptPubKey,
+		amount:       jsonItem.Amount,
+		redeemScript: redeemScript,
+	}
+	return item
+}
+
+func verifyUnlockItem(item *unlockItem) error {
+	flags := txscript.ScriptBip16 | txscript.ScriptVerifyDERSignatures | txscript.ScriptStrictMultiSig |  txscript.ScriptDiscourageUpgradableNops
+
+	redeemTx := wire.NewMsgTx(wire.TxVersion)
+	h, _ := btcdhash.NewHash(item.txid.CloneBytes())
+	prevOut := wire.NewOutPoint(h, uint32(item.out))
+	txIn := wire.NewTxIn(prevOut, nil, nil)
+	redeemTx.AddTxIn(txIn)
+
+	txOut := wire.NewTxOut(item.amount, item.scriptPubKey)
+	redeemTx.AddTxOut(txOut)
+
+	redeemTx.TxIn[0].SignatureScript = item.redeemScript
+
+	vm, err := txscript.NewEngine(item.scriptPubKey, redeemTx, 0, flags, nil, nil, -1)
+	if err != nil {
+		return err
+	}
+
+	err = vm.Execute()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+

swap/coinswap_test.go

@@ -0,0 +1,163 @@
+package swap
+
+import (
+	"os"
+	"testing"
+	"fmt"
+	"encoding/hex"
+
+	"github.com/btcsuite/btcutil"
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/txscript"
+	"github.com/btcsuite/btcd/wire"
+	btcdhash "github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/phoreproject/synapse/chainhash"
+	"github.com/sirupsen/logrus"
+)
+
+func TestMain(m *testing.M) {
+	logrus.SetLevel(logrus.DebugLevel)
+	retCode := m.Run()
+	os.Exit(retCode)
+}
+
+func TestComputeProofRootHash(t *testing.T) {
+	proofText := `[{"left":1,"hash":"1b74f997236425e2e42e6abcde553b2cabe64c67aebc297be921dc97624a9323"},{"left":1,"hash":"99e97ac121039b12ccae98b020e65be2e87fa76b152e1981edfd17ad9236ab9b"},{"left":1,"hash":"cdb63da025d64fcef8502360d4ff92ce73585f933097e4b8c9d6d4f42764e1a6"},{"left":0,"hash":"637a3ea530856c587067107829bf57fd487910b1f1688d6ef7b0eb2b6c5435f2"},{"left":0,"hash":"65567e55025fb9bd036a5421ee6ed948341c2db5c51ce8ad2dd84f4a6b254b49"},{"left":1,"hash":"b50c0cdef32a7091867c84c6aa1bdd106789d555e312c9e8fd676932ace570e8"},{"left":1,"hash":"747c93561ca44e0b3fcddeef4843e4c3e7332ae2aa273e2b17e126c37b531d3d"},{"left":1,"hash":"499bd10e09ca60d076fd335be8c3604ec46be3dcdadbcaf0f78b94ceb03f72f9"},{"left":1,"hash":"2b1a34ae4ce9f2e0ea7f7d6f9d1625c5eea5328ff5ecf738821103350aaa7804"},{"left":1,"hash":"774ec950bdf3310e4e00eea1fae3036ff40c387642d41619d27190e4e6026099"},{"left":0,"hash":"b1f90056ad3f8c857af752e9072ba20087d6c9934dd8264a61631ed0eb4fe5d1"},{"left":0,"hash":"51c1edc44b03532892322d49b2ae7c92da003d173731572d45664f408f33375e"},{"left":0,"hash":"64537e844116161caf73b89331131e22cb17874ada168070878537a577e767e7"},{"left":0,"hash":"7fc7d789a5a146c9b01c88f0871ed52740703d55468f0d3c0cb30e43a3207442"},{"left":1,"hash":"dd7ec62e2efd794cf52b357fda34a71e09e70e90882fe55d8af07cbfc02a8ecc"},{"left":0,"hash":"84741e23e7932f4eb9a87c407005748fcbe7f2639b00738510f7b6c3a1a310c5"},{"left":0,"hash":"9c1db4c5f3758f3593fe8ad40623ac07419785e6b25a2169acc779770c5b80b0"},{"left":0,"hash":"25bca9cf47142fe4cc0632dfe099f969b38cc8991d323df6644cb600e90bbf60"}]`
+	proofList := textToProofList(proofText)
+	hashText := "1b7509f59479bc2b048fc8a5d6f5b1b239b3d3d5e818d663817f250bcac7ff47"
+	hash, err := chainhash.NewHashFromStr(hashText)
+	if err != nil {
+		t.Fatal(err)
+	}
+	rootHashText := "40ed5ea75f6a5ab79ae109198703df1153b1cd272b122609d1bb3dc1b4ca376e"
+	rootHash, err := chainhash.NewHashFromStr(rootHashText)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	proofHash := computeProofRootHash(hash, proofList)
+
+	if proofHash != *rootHash {
+		t.Fatalf("Unmatched hash: root=%s computed=%s", rootHashText, proofHash.String())
+	}
+
+	btcec.ParsePubKey(nil, btcec.S256())
+}
+
+func TestUnlockItem(t * testing.T) {
+	unlockItemText := `{"txid":"03e73524b5bba21c4d2114900f6b8649e7ddc4480a8024c1ed09b883b5dbac45","out":0,"scriptPubKey":"210293704de00b9e47eee3848fc146fe659411ba839cda39534aa98a12611056939eac","amount":250000000000,"redeemScript":"483045022100c9ef24aa76cbb3b2341875c51af16aa0e1b17ac326203ab339c41c7578062f3b02203f5425c215872ee4a185f620a58baf986a9e614e7bac27b0df63412158af9d7401"}`
+	unlockItem := textToUnlockItem(unlockItemText)
+
+	err := verifyUnlockItem(&unlockItem)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+// This is from BTCD txscript sample code
+func TestBtcdExample(t * testing.T) {
+
+	// Ordinarily the private key would come from whatever storage mechanism
+	// is being used, but for this example just hard code it.
+	privKeyBytes, err := hex.DecodeString("22a47fa09a223f2aa079edf85a7c2" +
+		"d4f8720ee63e502ee2869afab7de234b80c")
+	if err != nil {
+		t.Fatal(err)
+		fmt.Println(err)
+		return
+	}
+	privKey, pubKey := btcec.PrivKeyFromBytes(btcec.S256(), privKeyBytes)
+	pubKeyHash := btcutil.Hash160(pubKey.SerializeCompressed())
+	addr, err := btcutil.NewAddressPubKeyHash(pubKeyHash,
+		&chaincfg.MainNetParams)
+	if err != nil {
+		t.Fatal(err)
+		fmt.Println(err)
+		return
+	}
+
+	// For this example, create a fake transaction that represents what
+	// would ordinarily be the real transaction that is being spent.  It
+	// contains a single output that pays to address in the amount of 1 BTC.
+	originTx := wire.NewMsgTx(wire.TxVersion)
+	prevOut := wire.NewOutPoint(&btcdhash.Hash{}, ^uint32(0))
+	txIn := wire.NewTxIn(prevOut, []byte{txscript.OP_0, txscript.OP_0}, nil)
+	originTx.AddTxIn(txIn)
+	pkScript, err := txscript.PayToAddrScript(addr)
+	if err != nil {
+		t.Fatal(err)
+		fmt.Println(err)
+		return
+	}
+	txOut := wire.NewTxOut(1, pkScript)
+	originTx.AddTxOut(txOut)
+	originTxHash := originTx.TxHash()
+
+	// Create the transaction to redeem the fake transaction.
+	redeemTx := wire.NewMsgTx(wire.TxVersion)
+
+	// Add the input(s) the redeeming transaction will spend.  There is no
+	// signature script at this point since it hasn't been created or signed
+	// yet, hence nil is provided for it.
+	prevOut = wire.NewOutPoint(&originTxHash, 0)
+	txIn = wire.NewTxIn(prevOut, nil, nil)
+	redeemTx.AddTxIn(txIn)
+
+	// Ordinarily this would contain that actual destination of the funds,
+	// but for this example don't bother.
+	txOut = wire.NewTxOut(0, nil)
+	redeemTx.AddTxOut(txOut)
+
+	// Sign the redeeming transaction.
+	lookupKey := func(a btcutil.Address) (*btcec.PrivateKey, bool, error) {
+		// Ordinarily this function would involve looking up the private
+		// key for the provided address, but since the only thing being
+		// signed in this example uses the address associated with the
+		// private key from above, simply return it with the compressed
+		// flag set since the address is using the associated compressed
+		// public key.
+		//
+		// NOTE: If you want to prove the code is actually signing the
+		// transaction properly, uncomment the following line which
+		// intentionally returns an invalid key to sign with, which in
+		// turn will result in a failure during the script execution
+		// when verifying the signature.
+		//
+		// privKey.D.SetInt64(12345)
+		//
+		return privKey, true, nil
+	}
+	// Notice that the script database parameter is nil here since it isn't
+	// used.  It must be specified when pay-to-script-hash transactions are
+	// being signed.
+	sigScript, err := txscript.SignTxOutput(&chaincfg.MainNetParams,
+		redeemTx, 0, originTx.TxOut[0].PkScript, txscript.SigHashAll,
+		txscript.KeyClosure(lookupKey), nil, nil)
+	if err != nil {
+		t.Fatal(err)
+		fmt.Println(err)
+		return
+	}
+	redeemTx.TxIn[0].SignatureScript = sigScript
+
+	// Prove that the transaction has been validly signed by executing the
+	// script pair.
+	flags := txscript.ScriptBip16 | txscript.ScriptVerifyDERSignatures |
+		txscript.ScriptStrictMultiSig |
+		txscript.ScriptDiscourageUpgradableNops
+	vm, err := txscript.NewEngine(originTx.TxOut[0].PkScript, redeemTx, 0,
+		flags, nil, nil, -1)
+	if err != nil {
+		t.Fatal(err)
+		fmt.Println(err)
+		return
+	}
+	if err := vm.Execute(); err != nil {
+		t.Fatal(err)
+		fmt.Println(err)
+		return
+	}
+	//fmt.Println("Transaction successfully signed")
+
+}