StateDB ZKInputs generation compatible with circom

- Add SignatureConstant to L1Tx.TxCompressedData
- ZKInputs generation works initial version working and compatible with circom Hermez circuit
    - Lots of small updates for circuits compatibility
- Update version (with new changes) of `go-iden3-crypto` & `go-merkletree`

common/l1tx.go

@@ -167,8 +167,9 @@ func (tx L1Tx) TxCompressedData() (*big.Int, error) {
 	if err != nil {
 		return nil, tracerr.Wrap(err)
 	}
+
 	var b [31]byte
-	// b[0:7] empty: no fee neither nonce
+	// b[0:7] empty: no ToBJJSign, no fee, no nonce
 	copy(b[7:11], tx.TokenID.Bytes())
 	copy(b[11:13], amountFloat16.Bytes())
 	toIdxBytes, err := tx.ToIdx.Bytes()
@@ -181,8 +182,8 @@ func (tx L1Tx) TxCompressedData() (*big.Int, error) {
 		return nil, tracerr.Wrap(err)
 	}
 	copy(b[19:25], fromIdxBytes[:])
-	copy(b[25:27], []byte{0, 1}) // TODO this will be generated by the ChainID config parameter
-	// b[27:] empty: no signature
+	copy(b[25:27], []byte{0, 0}) // TODO this will be generated by the ChainID config parameter
+	copy(b[27:31], SignatureConstantBytes[:])
 
 	bi := new(big.Int).SetBytes(b[:])
 	return bi, nil

common/l1tx_test.go

@@ -60,9 +60,9 @@ func TestL1TxCompressedData(t *testing.T) {
 	assert.Nil(t, err)
 
 	// test vector value generated from javascript implementation
-	expectedStr := "7307597389635308713748674793997299267460566876160"
+	expectedStr := "7307597389635308713748674793997299267459594577423"
 	assert.Equal(t, expectedStr, txCompressedData.String())
-	assert.Equal(t, "050004000000000003000000000002000100000000", hex.EncodeToString(txCompressedData.Bytes()))
+	assert.Equal(t, "0500040000000000030000000000020000c60be60f", hex.EncodeToString(txCompressedData.Bytes()))
 }
 
 func TestBytesDataAvailability(t *testing.T) {

common/pooll2tx.go

@@ -107,12 +107,6 @@ func NewPoolL2Tx(poolL2Tx *PoolL2Tx) (*PoolL2Tx, error) {
 // [ 32 bits ] signatureConstant // 4 bytes
 // Total bits compressed data:  241 bits // 31 bytes in *big.Int representation
 func (tx *PoolL2Tx) TxCompressedData() (*big.Int, error) {
-	// sigconstant
-	sc, ok := new(big.Int).SetString("3322668559", 10)
-	if !ok {
-		return nil, tracerr.Wrap(fmt.Errorf("error parsing SignatureConstant"))
-	}
-
 	amountFloat16, err := NewFloat16(tx.Amount)
 	if err != nil {
 		return nil, tracerr.Wrap(err)
@@ -141,8 +135,8 @@ func (tx *PoolL2Tx) TxCompressedData() (*big.Int, error) {
 		return nil, tracerr.Wrap(err)
 	}
 	copy(b[19:25], fromIdxBytes[:])
-	copy(b[25:27], []byte{0, 1}) // TODO this will be generated by the ChainID config parameter
-	copy(b[27:31], sc.Bytes())
+	copy(b[25:27], []byte{0, 0}) // TODO this will be generated by the ChainID config parameter
+	copy(b[27:31], SignatureConstantBytes[:])
 
 	bi := new(big.Int).SetBytes(b[:])
 	return bi, nil

common/pooll2tx_test.go

@@ -38,9 +38,9 @@ func TestTxCompressedData(t *testing.T) {
 	txCompressedData, err := tx.TxCompressedData()
 	assert.Nil(t, err)
 	// test vector value generated from javascript implementation
-	expectedStr := "1766847064778421992193717128424891165872736891548909569553540449389241871"
+	expectedStr := "1766847064778421992193717128424891165872736891548909569553540445094274575"
 	assert.Equal(t, expectedStr, txCompressedData.String())
-	assert.Equal(t, "010000000000060000000500040000000000030000000000020001c60be60f", hex.EncodeToString(txCompressedData.Bytes()))
+	assert.Equal(t, "010000000000060000000500040000000000030000000000020000c60be60f", hex.EncodeToString(txCompressedData.Bytes()))
 	tx = PoolL2Tx{
 		RqFromIdx: 7,
 		RqToIdx:   8,
@@ -112,18 +112,16 @@ func TestHashToSign(t *testing.T) {
 	_, err := hex.Decode(sk[:], []byte("0001020304050607080900010203040506070809000102030405060708090001"))
 	assert.Nil(t, err)
 	tx := PoolL2Tx{
-		FromIdx:     2,
-		ToIdx:       3,
-		Amount:      big.NewInt(4),
-		TokenID:     5,
-		Nonce:       6,
-		ToBJJ:       sk.Public(),
-		RqToEthAddr: ethCommon.HexToAddress("0xc58d29fA6e86E4FAe04DDcEd660d45BCf3Cb2370"),
-		RqToBJJ:     sk.Public(),
+		FromIdx:   2,
+		ToIdx:     3,
+		Amount:    big.NewInt(4),
+		TokenID:   5,
+		Nonce:     6,
+		ToEthAddr: ethCommon.HexToAddress("0xc58d29fA6e86E4FAe04DDcEd660d45BCf3Cb2370"),
 	}
 	toSign, err := tx.HashToSign()
 	assert.Nil(t, err)
-	assert.Equal(t, "13412877307445712067533842795279849753265998687662992184595695642580679868064", toSign.String())
+	assert.Equal(t, "1469900657138253851938022936440971384682713995864967090251961124784132925291", toSign.String())
 }
 
 func TestVerifyTxSignature(t *testing.T) {
@@ -142,7 +140,7 @@ func TestVerifyTxSignature(t *testing.T) {
 	}
 	toSign, err := tx.HashToSign()
 	assert.Nil(t, err)
-	assert.Equal(t, "13412877307445712067533842795279849753265998687662992184595695642580679868064", toSign.String())
+	assert.Equal(t, "18645218094210271622244722988708640202588315450486586312909439859037906375295", toSign.String())
 
 	sig := sk.SignPoseidon(toSign)
 	tx.Signature = sig.Compress()

common/tx.go

@@ -34,6 +34,13 @@ const (
 	TxIDLen = 12
 )
 
+var (
+	// SignatureConstantBytes contains the SignatureConstant in byte array
+	// format, which is equivalent to 3322668559 as uint32 in byte array in
+	// big endian representation.
+	SignatureConstantBytes = []byte{198, 11, 230, 15}
+)
+
 // TxID is the identifier of a Hermez network transaction
 type TxID [TxIDLen]byte
 

common/tx_test.go

@@ -3,11 +3,21 @@ package common
 import (
 	"database/sql"
 	"database/sql/driver"
+	"encoding/binary"
+	"encoding/hex"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
+func TestSignatureConstant(t *testing.T) {
+	signatureConstant := uint32(3322668559)
+	var signatureConstantBytes [4]byte
+	binary.BigEndian.PutUint32(signatureConstantBytes[:], signatureConstant)
+	assert.Equal(t, SignatureConstantBytes, signatureConstantBytes[:])
+	assert.Equal(t, "c60be60f", hex.EncodeToString(SignatureConstantBytes))
+}
+
 func TestTxIDScannerValue(t *testing.T) {
 	txid0 := &TxID{}
 	txid1 := &TxID{}

common/zk.go

@@ -58,14 +58,16 @@ type ZKInputs struct {
 	OldLastIdx *big.Int `json:"oldLastIdx"` // uint64 (max nLevels bits)
 	// OldStateRoot is the current state merkle tree root
 	OldStateRoot *big.Int `json:"oldStateRoot"` // Hash
-	// GlobalChainID is the blockchain ID (0 for Ethereum mainnet). This value can be get from the smart contract.
+	// GlobalChainID is the blockchain ID (0 for Ethereum mainnet). This
+	// value can be get from the smart contract.
 	GlobalChainID *big.Int `json:"globalChainID"` // uint16
-	// FeeIdxs is an array of merkle tree indexes where the coordinator will receive the accumulated fees
+	// FeeIdxs is an array of merkle tree indexes where the coordinator
+	// will receive the accumulated fees
 	FeeIdxs []*big.Int `json:"feeIdxs"` // uint64 (max nLevels bits), len: [maxFeeIdxs]
 
 	// accumulate fees
 	// FeePlanTokens contains all the tokenIDs for which the fees are being accumulated
-	FeePlanTokens []*big.Int `json:"feePlanTokens"` // uint32 (max 32 bits), len: [maxFeeIdxs]
+	FeePlanTokens []*big.Int `json:"feePlanTokens"` // uint32 (max nLevels bits), len: [maxFeeIdxs]
 
 	//
 	// Txs (L1&L2)
@@ -87,7 +89,9 @@ type ZKInputs struct {
 
 	// ToIdx
 	ToIdx []*big.Int `json:"toIdx"` // uint64 (max nLevels bits), len: [nTx]
-	// AuxToIdx is the Idx of the Tx that has 'toIdx==0', is the coordinator who will find which Idx corresponds to the 'toBJJAy' or 'toEthAddr'
+	// AuxToIdx is the Idx of the Tx that has 'toIdx==0', is the
+	// coordinator who will find which Idx corresponds to the 'toBJJAy' or
+	// 'toEthAddr'
 	AuxToIdx []*big.Int `json:"auxToIdx"` // uint64 (max nLevels bits), len: [nTx]
 	// ToBJJAy
 	ToBJJAy []*big.Int `json:"toBjjAy"` // big.Int, len: [nTx]
@@ -136,7 +140,9 @@ type ZKInputs struct {
 	// State MerkleTree Leafs transitions
 	//
 
-	// state 1, value of the sender (from) account leaf
+	// state 1, value of the sender (from) account leaf. The values at the
+	// moment pre-smtprocessor of the update (before updating the Sender
+	// leaf).
 	TokenID1  []*big.Int   `json:"tokenID1"`  // uint32, len: [nTx]
 	Nonce1    []*big.Int   `json:"nonce1"`    // uint64 (max 40 bits), len: [nTx]
 	Sign1     []*big.Int   `json:"sign1"`     // bool, len: [nTx]