From a7fe80f150e12d78565f0d4f627f2626db6ace76 Mon Sep 17 00:00:00 2001
From: arnaucube <root@arnaucube.com>
Date: Tue, 8 Sep 2020 18:41:32 +0200
Subject: [PATCH 1/3] Refactor ZKInputs & add struct initialization

Refactor ZKInputs & add struct initialization & add BJJCompressedTo256BigInts util
---
 common/token.go      |   6 +
 common/utils.go      |  18 +++
 common/utils_test.go |  39 +++++
 common/zk.go         | 345 ++++++++++++++++++++++++++++++-------------
 common/zk_test.go    |  15 ++
 5 files changed, 321 insertions(+), 102 deletions(-)
 create mode 100644 common/utils_test.go
 create mode 100644 common/zk_test.go

diff --git a/common/token.go b/common/token.go
index 22a60da..1888698 100644
--- a/common/token.go
+++ b/common/token.go
@@ -2,6 +2,7 @@ package common
 
 import (
 	"encoding/binary"
+	"math/big"
 	"time"
 
 	ethCommon "github.com/ethereum/go-ethereum/common"
@@ -34,3 +35,8 @@ func (t TokenID) Bytes() []byte {
 	binary.LittleEndian.PutUint32(tokenIDBytes[:], uint32(t))
 	return tokenIDBytes[:]
 }
+
+// BigInt returns the *big.Int representation of the TokenID
+func (t TokenID) BigInt() *big.Int {
+	return big.NewInt(int64(t))
+}
diff --git a/common/utils.go b/common/utils.go
index 9dad220..3ec26be 100644
--- a/common/utils.go
+++ b/common/utils.go
@@ -4,6 +4,7 @@ import (
 	"math/big"
 
 	ethCommon "github.com/ethereum/go-ethereum/common"
+	"github.com/iden3/go-iden3-crypto/babyjub"
 )
 
 // SwapEndianness swaps the order of the bytes in the slice.
@@ -19,3 +20,20 @@ func SwapEndianness(b []byte) []byte {
 func EthAddrToBigInt(a ethCommon.Address) *big.Int {
 	return new(big.Int).SetBytes(a.Bytes())
 }
+
+// BJJCompressedTo256BigInts returns a [256]*big.Int array with the bit
+// representation of the babyjub.PublicKeyComp
+func BJJCompressedTo256BigInts(pkComp babyjub.PublicKeyComp) [256]*big.Int {
+	var r [256]*big.Int
+	b := pkComp[:]
+
+	for i := 0; i < 256; i++ {
+		if b[i/8]&(1<<(i%8)) == 0 {
+			r[i] = big.NewInt(0)
+		} else {
+			r[i] = big.NewInt(1)
+		}
+	}
+
+	return r
+}
diff --git a/common/utils_test.go b/common/utils_test.go
new file mode 100644
index 0000000..e058de5
--- /dev/null
+++ b/common/utils_test.go
@@ -0,0 +1,39 @@
+package common
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/iden3/go-iden3-crypto/babyjub"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBJJCompressedTo256BigInt(t *testing.T) {
+	var pkComp babyjub.PublicKeyComp
+	r := BJJCompressedTo256BigInts(pkComp)
+	zero := big.NewInt(0)
+	for i := 0; i < 256; i++ {
+		assert.Equal(t, zero, r[i])
+	}
+
+	pkComp[0] = 3
+	r = BJJCompressedTo256BigInts(pkComp)
+	one := big.NewInt(1)
+	for i := 0; i < 256; i++ {
+		if i != 0 && i != 1 {
+			assert.Equal(t, zero, r[i])
+		} else {
+			assert.Equal(t, one, r[i])
+		}
+	}
+
+	pkComp[31] = 4
+	r = BJJCompressedTo256BigInts(pkComp)
+	for i := 0; i < 256; i++ {
+		if i != 0 && i != 1 && i != 250 {
+			assert.Equal(t, zero, r[i])
+		} else {
+			assert.Equal(t, one, r[i])
+		}
+	}
+}
diff --git a/common/zk.go b/common/zk.go
index d7d6892..1b7d378 100644
--- a/common/zk.go
+++ b/common/zk.go
@@ -1,6 +1,6 @@
 // Package common contains all the common data structures used at the
 // hermez-node, zk.go contains the zkSnark inputs used to generate the proof
-//nolint:deadcode,structcheck, unused
+//nolint:deadcode,structcheck,unused
 package common
 
 import "math/big"
@@ -20,127 +20,268 @@ type maxFeeTx uint32
 
 // ZKInputs represents the inputs that will be used to generate the zkSNARK proof
 type ZKInputs struct {
+	//
+	// General
+	//
+
 	// inputs for final `hashGlobalInputs`
-	// oldLastIdx is the last index assigned to an account
-	oldLastIdx *big.Int // uint64 (max nLevels bits)
-	// oldStateRoot is the current state merkle tree root
-	oldStateRoot *big.Int // Hash
-	// globalChainID is the blockchain ID (0 for Ethereum mainnet). This value can be get from the smart contract.
-	globalChainID *big.Int // uint16
-	// feeIdxs is an array of merkle tree indexes where the coordinator will receive the accumulated fees
-	feeIdxs []*big.Int // uint64 (max nLevels bits), len: [maxFeeTx]
+	// OldLastIdx is the last index assigned to an account
+	OldLastIdx *big.Int // uint64 (max nLevels bits)
+	// OldStateRoot is the current state merkle tree root
+	OldStateRoot *big.Int // Hash
+	// GlobalChainID is the blockchain ID (0 for Ethereum mainnet). This value can be get from the smart contract.
+	GlobalChainID *big.Int // uint16
+	// FeeIdxs is an array of merkle tree indexes where the coordinator will receive the accumulated fees
+	FeeIdxs []*big.Int // uint64 (max nLevels bits), len: [maxFeeTx]
 
 	// accumulate fees
-	// feePlanTokens contains all the tokenIDs for which the fees are being accumulated
-	feePlanTokens []*big.Int // uint32 (max 32 bits), len: [maxFeeTx]
+	// FeePlanTokens contains all the tokenIDs for which the fees are being accumulated
+	FeePlanTokens []*big.Int // uint32 (max 32 bits), len: [maxFeeTx]
 
-	// Intermediary States to parallelize witness computation
-	// decode-tx
-	// imOnChain indicates if tx is L1 (true) or L2 (false)
-	imOnChain []*big.Int // bool, len: [nTx - 1]
-	// imOutIdx current index account for each Tx
-	imOutIdx []*big.Int // uint64 (max nLevels bits), len: [nTx - 1]
-	// rollup-tx
-	// imStateRoot root at the moment of the Tx, the state root value once the Tx is processed into the state tree
-	imStateRoot []*big.Int // Hash, len: [nTx - 1]
-	// imExitTree root at the moment of the Tx the value once the Tx is processed into the exit tree
-	imExitRoot []*big.Int // Hash, len: [nTx - 1]
-	// imAccFeeOut accumulated fees once the Tx is processed
-	imAccFeeOut [][]*big.Int // big.Int, len: [nTx - 1][maxFeeTx]
-	// fee-tx
-	// imStateRootFee root at the moment of the Tx, the state root value once the Tx is processed into the state tree
-	imStateRootFee []*big.Int // Hash, len: [maxFeeTx - 1]
-	// imInitStateRootFee state root once all L1-L2 tx are processed (before computing the fees-tx)
-	imInitStateRootFee *big.Int // Hash
-	// imFinalAccFee final accumulated fees (before computing the fees-tx)
-	imFinalAccFee []*big.Int // big.Int, len: [maxFeeTx - 1]
+	//
+	// Txs (L1&L2)
+	//
 
 	// transaction L1-L2
-	// txCompressedData
-	txCompressedData []*big.Int // big.Int (max 251 bits), len: [nTx]
-	// txCompressedDataV2
-	txCompressedDataV2 []*big.Int // big.Int (max 193 bits), len: [nTx]
-	// fromIdx
-	fromIdx []*big.Int // uint64 (max nLevels bits), len: [nTx]
-	// auxFromIdx is the Idx of the new created account which is consequence of a L1CreateAccountTx
-	auxFromIdx []*big.Int // uint64 (max nLevels bits), len: [nTx]
-
-	// toIdx
-	toIdx []*big.Int // 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 []*big.Int // uint64 (max nLevels bits), len: [nTx]
-	// toBjjAy
-	toBjjAy []*big.Int // big.Int, len: [nTx]
-	// toEthAddr
-	toEthAddr []*big.Int // ethCommon.Address, len: [nTx]
-
-	// onChain determines if is L1 (1/true) or L2 (0/false)
-	onChain []*big.Int // bool, len: [nTx]
-	// newAccount boolean (0/1) flag to set L1 tx creates a new account
-	newAccount []*big.Int // bool, len: [nTx]
-	// rqOffset relative transaction position to be linked. Used to perform atomic transactions.
-	rqOffset []*big.Int // uint8 (max 3 bits), len: [nTx]
+	// TxCompressedData
+	TxCompressedData []*big.Int // big.Int (max 251 bits), len: [nTx]
+	// TxCompressedDataV2, only used in L2Txs, in L1Txs is set to 0
+	TxCompressedDataV2 []*big.Int // big.Int (max 193 bits), len: [nTx]
+
+	// FromIdx
+	FromIdx []*big.Int // uint64 (max nLevels bits), len: [nTx]
+	// AuxFromIdx is the Idx of the new created account which is consequence of a L1CreateAccountTx
+	AuxFromIdx []*big.Int // uint64 (max nLevels bits), len: [nTx]
+
+	// ToIdx
+	ToIdx []*big.Int // 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 []*big.Int // uint64 (max nLevels bits), len: [nTx]
+	// ToBJJAy
+	ToBJJAy []*big.Int // big.Int, len: [nTx]
+	// ToEthAddr
+	ToEthAddr []*big.Int // ethCommon.Address, len: [nTx]
+
+	// OnChain determines if is L1 (1/true) or L2 (0/false)
+	OnChain []*big.Int // bool, len: [nTx]
+	// NewAccount boolean (0/1) flag set 'true' when L1 tx creates a new account (fromIdx==0)
+	NewAccount []*big.Int // bool, len: [nTx]
+
+	//
+	// Txs/L1Txs
+	//
+	// transaction L1
+	// LoadAmountF encoded as float16
+	LoadAmountF []*big.Int // uint16, len: [nTx]
+	// FromEthAddr
+	FromEthAddr []*big.Int // ethCommon.Address, len: [nTx]
+	// FromBJJCompressed boolean encoded where each value is a *big.Int
+	FromBJJCompressed [][256]*big.Int // bool array, len: [nTx][256]
+
+	//
+	// Txs/L2Txs
+	//
+
+	// RqOffset relative transaction position to be linked. Used to perform atomic transactions.
+	RqOffset []*big.Int // uint8 (max 3 bits), len: [nTx]
 
 	// transaction L2 request data
-	// rqTxCompressedDataV2
-	rqTxCompressedDataV2 []*big.Int // big.Int (max 251 bits), len: [nTx]
-	// rqToEthAddr
-	rqToEthAddr []*big.Int // ethCommon.Address, len: [nTx]
-	// rqToBjjAy
-	rqToBjjAy []*big.Int // big.Int, len: [nTx]
+	// RqTxCompressedDataV2
+	RqTxCompressedDataV2 []*big.Int // big.Int (max 251 bits), len: [nTx]
+	// RqToEthAddr
+	RqToEthAddr []*big.Int // ethCommon.Address, len: [nTx]
+	// RqToBJJAy
+	RqToBJJAy []*big.Int // big.Int, len: [nTx]
 
 	// transaction L2 signature
-	// s
-	s []*big.Int // big.Int, len: [nTx]
-	// r8x
-	r8x []*big.Int // big.Int, len: [nTx]
-	// r8y
-	r8y []*big.Int // big.Int, len: [nTx]
+	// S
+	S []*big.Int // big.Int, len: [nTx]
+	// R8x
+	R8x []*big.Int // big.Int, len: [nTx]
+	// R8y
+	R8y []*big.Int // big.Int, len: [nTx]
 
-	// transaction L1
-	// loadAmountF encoded as float16
-	loadAmountF []*big.Int // uint16, len: [nTx]
-	// fromEthAddr
-	fromEthAddr []*big.Int // ethCommon.Address, len: [nTx]
-	// fromBjjCompressed boolean encoded where each value is a *big.Int
-	fromBjjCompressed [][]*big.Int // bool array, len: [nTx][256]
+	//
+	// State MerkleTree Leafs transitions
+	//
 
 	// state 1, value of the sender (from) account leaf
-	tokenID1  []*big.Int   // uint32, len: [nTx]
-	nonce1    []*big.Int   // uint64 (max 40 bits), len: [nTx]
-	sign1     []*big.Int   // bool, len: [nTx]
-	balance1  []*big.Int   // big.Int (max 192 bits), len: [nTx]
-	ay1       []*big.Int   // big.Int, len: [nTx]
-	ethAddr1  []*big.Int   // ethCommon.Address, len: [nTx]
-	siblings1 [][]*big.Int // big.Int, len: [nTx][nLevels + 1]
+	TokenID1  []*big.Int   // uint32, len: [nTx]
+	Nonce1    []*big.Int   // uint64 (max 40 bits), len: [nTx]
+	Sign1     []*big.Int   // bool, len: [nTx]
+	Balance1  []*big.Int   // big.Int (max 192 bits), len: [nTx]
+	Ay1       []*big.Int   // big.Int, len: [nTx]
+	EthAddr1  []*big.Int   // ethCommon.Address, len: [nTx]
+	Siblings1 [][]*big.Int // big.Int, len: [nTx][nLevels + 1]
 	// Required for inserts and deletes, values of the CircomProcessorProof (smt insert proof)
-	isOld0_1  []*big.Int // bool, len: [nTx]
-	oldKey1   []*big.Int // uint64 (max 40 bits), len: [nTx]
-	oldValue1 []*big.Int // Hash, len: [nTx]
+	IsOld0_1  []*big.Int // bool, len: [nTx]
+	OldKey1   []*big.Int // uint64 (max 40 bits), len: [nTx]
+	OldValue1 []*big.Int // Hash, len: [nTx]
 
 	// state 2, value of the receiver (to) account leaf
-	tokenID2  []*big.Int   // uint32, len: [nTx]
-	nonce2    []*big.Int   // uint64 (max 40 bits), len: [nTx]
-	sign2     []*big.Int   // bool, len: [nTx]
-	balance2  []*big.Int   // big.Int (max 192 bits), len: [nTx]
-	ay2       []*big.Int   // big.Int, len: [nTx]
-	ethAddr2  []*big.Int   // ethCommon.Address, len: [nTx]
-	siblings2 [][]*big.Int // big.Int, len: [nTx][nLevels + 1]
+	// if Tx is an Exit, state 2 is used for the Exit Merkle Proof
+	TokenID2  []*big.Int   // uint32, len: [nTx]
+	Nonce2    []*big.Int   // uint64 (max 40 bits), len: [nTx]
+	Sign2     []*big.Int   // bool, len: [nTx]
+	Balance2  []*big.Int   // big.Int (max 192 bits), len: [nTx]
+	Ay2       []*big.Int   // big.Int, len: [nTx]
+	EthAddr2  []*big.Int   // ethCommon.Address, len: [nTx]
+	Siblings2 [][]*big.Int // big.Int, len: [nTx][nLevels + 1]
 	// newExit determines if an exit transaction has to create a new leaf in the exit tree
-	newExit []*big.Int // bool, len: [nTx]
+	NewExit []*big.Int // bool, len: [nTx]
 	// Required for inserts and deletes, values of the CircomProcessorProof (smt insert proof)
-	isOld0_2  []*big.Int // bool, len: [nTx]
-	oldKey2   []*big.Int // uint64 (max 40 bits), len: [nTx]
-	oldValue2 []*big.Int // Hash, len: [nTx]
+	IsOld0_2  []*big.Int // bool, len: [nTx]
+	OldKey2   []*big.Int // uint64 (max 40 bits), len: [nTx]
+	OldValue2 []*big.Int // Hash, len: [nTx]
 
 	// state 3, value of the account leaf receiver of the Fees
 	// fee tx
 	// State fees
-	tokenID3  []*big.Int   // uint32, len: [maxFeeTx]
-	nonce3    []*big.Int   // uint64 (max 40 bits), len: [maxFeeTx]
-	sign3     []*big.Int   // bool, len: [maxFeeTx]
-	balance3  []*big.Int   // big.Int (max 192 bits), len: [maxFeeTx]
-	ay3       []*big.Int   // big.Int, len: [maxFeeTx]
-	ethAddr3  []*big.Int   // ethCommon.Address, len: [maxFeeTx]
-	siblings3 [][]*big.Int // Hash, len: [maxFeeTx][nLevels + 1]
+	TokenID3  []*big.Int   // uint32, len: [maxFeeTx]
+	Nonce3    []*big.Int   // uint64 (max 40 bits), len: [maxFeeTx]
+	Sign3     []*big.Int   // bool, len: [maxFeeTx]
+	Balance3  []*big.Int   // big.Int (max 192 bits), len: [maxFeeTx]
+	Ay3       []*big.Int   // big.Int, len: [maxFeeTx]
+	EthAddr3  []*big.Int   // ethCommon.Address, len: [maxFeeTx]
+	Siblings3 [][]*big.Int // Hash, len: [maxFeeTx][nLevels + 1]
+
+	//
+	// Intermediate States
+	//
+
+	// Intermediate States to parallelize witness computation
+	// decode-tx
+	// ISOnChain indicates if tx is L1 (true) or L2 (false)
+	ISOnChain []*big.Int // bool, len: [nTx - 1]
+	// ISOutIdx current index account for each Tx
+	ISOutIdx []*big.Int // uint64 (max nLevels bits), len: [nTx - 1]
+	// rollup-tx
+	// ISStateRoot root at the moment of the Tx, the state root value once the Tx is processed into the state tree
+	ISStateRoot []*big.Int // Hash, len: [nTx - 1]
+	// ISExitTree root at the moment of the Tx the value once the Tx is processed into the exit tree
+	ISExitRoot []*big.Int // Hash, len: [nTx - 1]
+	// ISAccFeeOut accumulated fees once the Tx is processed
+	ISAccFeeOut [][]*big.Int // big.Int, len: [nTx - 1][maxFeeTx]
+	// fee-tx
+	// ISStateRootFee root at the moment of the Tx, the state root value once the Tx is processed into the state tree
+	ISStateRootFee []*big.Int // Hash, len: [maxFeeTx - 1]
+	// ISInitStateRootFee state root once all L1-L2 tx are processed (before computing the fees-tx)
+	ISInitStateRootFee *big.Int // Hash
+	// ISFinalAccFee final accumulated fees (before computing the fees-tx)
+	ISFinalAccFee []*big.Int // big.Int, len: [maxFeeTx - 1]
+}
+
+// NewZKInputs returns a pointer to an initialized struct of ZKInputs
+func NewZKInputs(nTx, maxFeeTx, nLevels int) *ZKInputs {
+	zki := &ZKInputs{}
+
+	// General
+	zki.OldLastIdx = big.NewInt(0)
+	zki.OldStateRoot = big.NewInt(0)
+	zki.GlobalChainID = big.NewInt(0)
+	zki.FeeIdxs = newSlice(maxFeeTx)
+	zki.FeePlanTokens = newSlice(maxFeeTx)
+
+	// Txs
+	zki.TxCompressedData = newSlice(nTx)
+	zki.TxCompressedDataV2 = newSlice(nTx)
+	zki.FromIdx = newSlice(nTx)
+	zki.AuxFromIdx = newSlice(nTx)
+	zki.ToIdx = newSlice(nTx)
+	zki.AuxToIdx = newSlice(nTx)
+	zki.ToBJJAy = newSlice(nTx)
+	zki.ToEthAddr = newSlice(nTx)
+	zki.OnChain = newSlice(nTx)
+	zki.NewAccount = newSlice(nTx)
+
+	// L1
+	zki.LoadAmountF = newSlice(nTx)
+	zki.FromEthAddr = newSlice(nTx)
+	zki.FromBJJCompressed = make([][256]*big.Int, nTx)
+	for i := 0; i < len(zki.FromBJJCompressed); i++ {
+		// zki.FromBJJCompressed[i] = newSlice(256)
+		for j := 0; j < 256; j++ {
+			zki.FromBJJCompressed[i][j] = big.NewInt(0)
+		}
+	}
+
+	// L2
+	zki.RqOffset = newSlice(nTx)
+	zki.RqTxCompressedDataV2 = newSlice(nTx)
+	zki.RqToEthAddr = newSlice(nTx)
+	zki.RqToBJJAy = newSlice(nTx)
+	zki.S = newSlice(nTx)
+	zki.R8x = newSlice(nTx)
+	zki.R8y = newSlice(nTx)
+
+	// State MerkleTree Leafs transitions
+	zki.TokenID1 = newSlice(nTx)
+	zki.Nonce1 = newSlice(nTx)
+	zki.Sign1 = newSlice(nTx)
+	zki.Balance1 = newSlice(nTx)
+	zki.Ay1 = newSlice(nTx)
+	zki.EthAddr1 = newSlice(nTx)
+	zki.Siblings1 = make([][]*big.Int, nTx)
+	for i := 0; i < len(zki.Siblings1); i++ {
+		zki.Siblings1[i] = newSlice(nLevels + 1)
+	}
+	zki.IsOld0_1 = newSlice(nTx)
+	zki.OldKey1 = newSlice(nTx)
+	zki.OldValue1 = newSlice(nTx)
+
+	zki.TokenID2 = newSlice(nTx)
+	zki.Nonce2 = newSlice(nTx)
+	zki.Sign2 = newSlice(nTx)
+	zki.Balance2 = newSlice(nTx)
+	zki.Ay2 = newSlice(nTx)
+	zki.EthAddr2 = newSlice(nTx)
+	zki.Siblings2 = make([][]*big.Int, nTx)
+	for i := 0; i < len(zki.Siblings2); i++ {
+		zki.Siblings2[i] = newSlice(nLevels + 1)
+	}
+	zki.NewExit = newSlice(nTx)
+	zki.IsOld0_2 = newSlice(nTx)
+	zki.OldKey2 = newSlice(nTx)
+	zki.OldValue2 = newSlice(nTx)
+
+	zki.TokenID3 = newSlice(maxFeeTx)
+	zki.Nonce3 = newSlice(maxFeeTx)
+	zki.Sign3 = newSlice(maxFeeTx)
+	zki.Balance3 = newSlice(maxFeeTx)
+	zki.Ay3 = newSlice(maxFeeTx)
+	zki.EthAddr3 = newSlice(maxFeeTx)
+	zki.Siblings3 = make([][]*big.Int, maxFeeTx)
+	for i := 0; i < len(zki.Siblings3); i++ {
+		zki.Siblings3[i] = newSlice(nLevels + 1)
+	}
+
+	// Intermediate States
+	zki.ISOnChain = newSlice(nTx - 1)
+	zki.ISOutIdx = newSlice(nTx - 1)
+	zki.ISStateRoot = newSlice(nTx - 1)
+	zki.ISExitRoot = newSlice(nTx - 1)
+	zki.ISAccFeeOut = make([][]*big.Int, nTx-1)
+	for i := 0; i < len(zki.ISAccFeeOut); i++ {
+		zki.ISAccFeeOut[i] = newSlice(maxFeeTx)
+	}
+	zki.ISStateRootFee = newSlice(maxFeeTx - 1)
+	zki.ISInitStateRootFee = big.NewInt(0)
+	zki.ISFinalAccFee = newSlice(maxFeeTx - 1)
+
+	return zki
+}
+
+// newSlice returns a []*big.Int slice of length n with values initialized at
+// 0.
+// Is used to initialize all *big.Ints of the ZKInputs data structure, so when
+// the transactions are processed and the ZKInputs filled, there is no need to
+// set all the elements, and if a transaction does not use a parameter, can be
+// leaved as it is in the ZKInputs, as will be 0, so later when using the
+// ZKInputs to generate the zkSnark proof there is no 'nil'/'null' values.
+func newSlice(n int) []*big.Int {
+	s := make([]*big.Int, n)
+	for i := 0; i < len(s); i++ {
+		s[i] = big.NewInt(0)
+	}
+	return s
 }
diff --git a/common/zk_test.go b/common/zk_test.go
new file mode 100644
index 0000000..8767838
--- /dev/null
+++ b/common/zk_test.go
@@ -0,0 +1,15 @@
+package common
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestZKInputs(t *testing.T) {
+	zki := NewZKInputs(100, 24, 32)
+	_, err := json.Marshal(zki)
+	require.Nil(t, err)
+	// fmt.Println(string(s))
+}

From aa0bde61d223fd2894f6a2256c0b6272a6b5f1d8 Mon Sep 17 00:00:00 2001
From: arnaucube <root@arnaucube.com>
Date: Wed, 9 Sep 2020 14:40:55 +0200
Subject: [PATCH 2/3] Add StateDB ZKInputs generation for L1 & L2 Txs

---
 batchbuilder/batchbuilder.go    |   4 +-
 common/l2tx.go                  |  25 +++++
 coordinator/coordinator.go      |   3 +-
 db/statedb/statedb.go           |   2 +
 db/statedb/txprocessors.go      | 167 ++++++++++++++++++++++++++++++--
 db/statedb/txprocessors_test.go |  47 +++++++--
 db/statedb/utils.go             |  17 ++++
 7 files changed, 245 insertions(+), 20 deletions(-)
 create mode 100644 db/statedb/utils.go

diff --git a/batchbuilder/batchbuilder.go b/batchbuilder/batchbuilder.go
index 0f864e5..35c5ad3 100644
--- a/batchbuilder/batchbuilder.go
+++ b/batchbuilder/batchbuilder.go
@@ -51,8 +51,8 @@ func (bb *BatchBuilder) Reset(batchNum common.BatchNum, fromSynchronizer bool) e
 }
 
 // BuildBatch takes the transactions and returns the common.ZKInputs of the next batch
-func (bb *BatchBuilder) BuildBatch(configBatch *ConfigBatch, l1usertxs, l1coordinatortxs []*common.L1Tx, l2txs []*common.L2Tx, tokenIDs []common.TokenID) (*common.ZKInputs, error) {
-	zkInputs, _, err := bb.localStateDB.ProcessTxs(false, l1usertxs, l1coordinatortxs, l2txs)
+func (bb *BatchBuilder) BuildBatch(configBatch *ConfigBatch, l1usertxs, l1coordinatortxs []*common.L1Tx, pooll2txs []*common.PoolL2Tx, tokenIDs []common.TokenID) (*common.ZKInputs, error) {
+	zkInputs, _, err := bb.localStateDB.ProcessTxs(false, true, l1usertxs, l1coordinatortxs, pooll2txs)
 	if err != nil {
 		return nil, err
 	}
diff --git a/common/l2tx.go b/common/l2tx.go
index 44a0283..3d49694 100644
--- a/common/l2tx.go
+++ b/common/l2tx.go
@@ -30,3 +30,28 @@ func (tx *L2Tx) Tx() *Tx {
 		Type:    tx.Type,
 	}
 }
+
+// PoolL2Tx returns the data structure of PoolL2Tx with the parameters of a
+// L2Tx filled
+func (tx *L2Tx) PoolL2Tx() *PoolL2Tx {
+	return &PoolL2Tx{
+		TxID:     tx.TxID,
+		BatchNum: tx.BatchNum,
+		FromIdx:  tx.FromIdx,
+		ToIdx:    tx.ToIdx,
+		Amount:   tx.Amount,
+		Fee:      tx.Fee,
+		Nonce:    tx.Nonce,
+		Type:     tx.Type,
+	}
+}
+
+// L2TxsToPoolL2Txs returns an array of []*PoolL2Tx from an array of []*L2Tx,
+// where the PoolL2Tx only have the parameters of a L2Tx filled.
+func L2TxsToPoolL2Txs(txs []*L2Tx) []*PoolL2Tx {
+	var r []*PoolL2Tx
+	for _, tx := range txs {
+		r = append(r, tx.PoolL2Tx())
+	}
+	return r
+}
diff --git a/coordinator/coordinator.go b/coordinator/coordinator.go
index a2d1d1b..85b6a98 100644
--- a/coordinator/coordinator.go
+++ b/coordinator/coordinator.go
@@ -221,8 +221,7 @@ func (c *Coordinator) forgeSequence() error {
 	configBatch := &batchbuilder.ConfigBatch{
 		ForgerAddress: c.config.ForgerAddress,
 	}
-	l2Txs := common.PoolL2TxsToL2Txs(poolL2Txs)
-	zkInputs, err := c.batchBuilder.BuildBatch(configBatch, l1UserTxsExtra, l1OperatorTxs, l2Txs, nil) // TODO []common.TokenID --> feesInfo
+	zkInputs, err := c.batchBuilder.BuildBatch(configBatch, l1UserTxsExtra, l1OperatorTxs, poolL2Txs, nil) // TODO []common.TokenID --> feesInfo
 	if err != nil {
 		return err
 	}
diff --git a/db/statedb/statedb.go b/db/statedb/statedb.go
index 5d69494..e5e83ff 100644
--- a/db/statedb/statedb.go
+++ b/db/statedb/statedb.go
@@ -43,6 +43,8 @@ type StateDB struct {
 	mt           *merkletree.MerkleTree
 	// idx holds the current Idx that the BatchBuilder is using
 	idx common.Idx
+	zki *common.ZKInputs
+	i   int // i is used for zki
 }
 
 // NewStateDB creates a new StateDB, allowing to use an in-memory or in-disk
diff --git a/db/statedb/txprocessors.go b/db/statedb/txprocessors.go
index 280942c..d3ea768 100644
--- a/db/statedb/txprocessors.go
+++ b/db/statedb/txprocessors.go
@@ -1,8 +1,12 @@
 package statedb
 
 import (
+	"bytes"
+	"errors"
+	"fmt"
 	"math/big"
 
+	ethCommon "github.com/ethereum/go-ethereum/common"
 	"github.com/hermeznetwork/hermez-node/common"
 	"github.com/iden3/go-iden3-crypto/poseidon"
 	"github.com/iden3/go-merkletree"
@@ -10,19 +14,42 @@ import (
 	"github.com/iden3/go-merkletree/db/memory"
 )
 
-// keyidx is used as key in the db to store the current Idx
-var keyidx = []byte("idx")
+var (
+	// keyidx is used as key in the db to store the current Idx
+	keyidx = []byte("idx")
+
+	ffAddr = ethCommon.HexToAddress("0xffffffffffffffffffffffffffffffffffffffff")
+)
+
+func (s *StateDB) resetZKInputs() {
+	s.zki = nil
+	s.i = 0
+}
 
 // ProcessTxs process the given L1Txs & L2Txs applying the needed updates to
 // the StateDB depending on the transaction Type. Returns the common.ZKInputs
 // to generate the SnarkProof later used by the BatchBuilder, and if
 // cmpExitTree is set to true, returns common.ExitTreeLeaf that is later used
 // by the Synchronizer to update the HistoryDB.
-func (s *StateDB) ProcessTxs(cmpExitTree bool, l1usertxs, l1coordinatortxs []*common.L1Tx, l2txs []*common.L2Tx) (*common.ZKInputs, []*common.ExitInfo, error) {
+func (s *StateDB) ProcessTxs(cmpExitTree, cmpZKInputs bool, l1usertxs, l1coordinatortxs []*common.L1Tx, l2txs []*common.PoolL2Tx) (*common.ZKInputs, []*common.ExitInfo, error) {
 	var err error
 	var exitTree *merkletree.MerkleTree
 	exits := make(map[common.Idx]common.Account)
 
+	if s.zki != nil {
+		return nil, nil, errors.New("Expected StateDB.zki==nil, something went wrong ans is not empty")
+	}
+	defer s.resetZKInputs()
+
+	nTx := len(l1usertxs) + len(l1coordinatortxs) + len(l2txs)
+	if nTx == 0 {
+		return nil, nil, nil // TBD if return an error in the case of no Txs to process
+	}
+
+	if cmpZKInputs {
+		s.zki = common.NewZKInputs(nTx, 24, 32) // TODO this values will be parameters of the function
+	}
+
 	// TBD if ExitTree is only in memory or stored in disk, for the moment
 	// only needed in memory
 	exitTree, err = merkletree.NewMerkleTree(memory.NewMemoryStorage(), s.mt.MaxLevels())
@@ -30,7 +57,8 @@ func (s *StateDB) ProcessTxs(cmpExitTree bool, l1usertxs, l1coordinatortxs []*co
 		return nil, nil, err
 	}
 
-	for _, tx := range l1coordinatortxs {
+	// assumption: l1usertx are sorted by L1Tx.Position
+	for _, tx := range l1usertxs {
 		exitIdx, exitAccount, err := s.processL1Tx(exitTree, tx)
 		if err != nil {
 			return nil, nil, err
@@ -38,8 +66,11 @@ func (s *StateDB) ProcessTxs(cmpExitTree bool, l1usertxs, l1coordinatortxs []*co
 		if exitIdx != nil && cmpExitTree {
 			exits[*exitIdx] = *exitAccount
 		}
+		if s.zki != nil {
+			s.i++
+		}
 	}
-	for _, tx := range l1usertxs {
+	for _, tx := range l1coordinatortxs {
 		exitIdx, exitAccount, err := s.processL1Tx(exitTree, tx)
 		if err != nil {
 			return nil, nil, err
@@ -47,6 +78,9 @@ func (s *StateDB) ProcessTxs(cmpExitTree bool, l1usertxs, l1coordinatortxs []*co
 		if exitIdx != nil && cmpExitTree {
 			exits[*exitIdx] = *exitAccount
 		}
+		if s.zki != nil {
+			s.i++
+		}
 	}
 	for _, tx := range l2txs {
 		exitIdx, exitAccount, err := s.processL2Tx(exitTree, tx)
@@ -56,9 +90,12 @@ func (s *StateDB) ProcessTxs(cmpExitTree bool, l1usertxs, l1coordinatortxs []*co
 		if exitIdx != nil && cmpExitTree {
 			exits[*exitIdx] = *exitAccount
 		}
+		if s.zki != nil {
+			s.i++
+		}
 	}
 
-	if !cmpExitTree {
+	if !cmpExitTree && !cmpZKInputs {
 		return nil, nil, nil
 	}
 
@@ -93,15 +130,78 @@ func (s *StateDB) ProcessTxs(cmpExitTree bool, l1usertxs, l1coordinatortxs []*co
 		}
 		exitInfos = append(exitInfos, ei)
 	}
+	if !cmpZKInputs {
+		return nil, exitInfos, nil
+	}
+
+	// compute last ZKInputs parameters
+	s.zki.OldLastIdx = (s.idx - 1).BigInt()
+	s.zki.OldStateRoot = s.mt.Root().BigInt()
+	s.zki.GlobalChainID = big.NewInt(0) // TODO, 0: ethereum, get this from config file
+	// zki.FeeIdxs = ? // TODO, this will be get from the config file
+	tokenIDs, err := s.getTokenIDsBigInt(l1usertxs, l1coordinatortxs, l2txs)
+	if err != nil {
+		return nil, nil, err
+	}
+	s.zki.FeePlanTokens = tokenIDs
+
+	// s.zki.ISInitStateRootFee = s.mt.Root().BigInt()
+	// compute fees
+
+	// once fees are computed
 
 	// return exitInfos, so Synchronizer will be able to store it into
 	// HistoryDB for the concrete BatchNum
-	return nil, exitInfos, nil
+	return s.zki, exitInfos, nil
+}
+
+// getTokenIDsBigInt returns the list of TokenIDs in *big.Int format
+func (s *StateDB) getTokenIDsBigInt(l1usertxs, l1coordinatortxs []*common.L1Tx, l2txs []*common.PoolL2Tx) ([]*big.Int, error) {
+	tokenIDs := make(map[common.TokenID]bool)
+	for i := 0; i < len(l1usertxs); i++ {
+		tokenIDs[l1usertxs[i].TokenID] = true
+	}
+	for i := 0; i < len(l1coordinatortxs); i++ {
+		tokenIDs[l1coordinatortxs[i].TokenID] = true
+	}
+	for i := 0; i < len(l2txs); i++ {
+		// as L2Tx does not have parameter TokenID, get it from the
+		// AccountsDB (in the StateDB)
+		acc, err := s.GetAccount(l2txs[i].ToIdx)
+		if err != nil {
+			return nil, err
+		}
+		tokenIDs[acc.TokenID] = true
+	}
+	var tBI []*big.Int
+	for t := range tokenIDs {
+		tBI = append(tBI, t.BigInt())
+	}
+	return tBI, nil
 }
 
 // processL1Tx process the given L1Tx applying the needed updates to the
 // StateDB depending on the transaction Type.
 func (s *StateDB) processL1Tx(exitTree *merkletree.MerkleTree, tx *common.L1Tx) (*common.Idx, *common.Account, error) {
+	// ZKInputs
+	if s.zki != nil {
+		// Txs
+		// s.zki.TxCompressedData[s.i] = tx.TxCompressedData() // uncomment once L1Tx.TxCompressedData is ready
+		s.zki.FromIdx[s.i] = tx.FromIdx.BigInt()
+		s.zki.ToIdx[s.i] = tx.ToIdx.BigInt()
+		s.zki.OnChain[s.i] = big.NewInt(1)
+
+		// L1Txs
+		s.zki.LoadAmountF[s.i] = tx.LoadAmount
+		s.zki.FromEthAddr[s.i] = common.EthAddrToBigInt(tx.FromEthAddr)
+		if tx.FromBJJ != nil {
+			s.zki.FromBJJCompressed[s.i] = common.BJJCompressedTo256BigInts(tx.FromBJJ.Compress())
+		}
+
+		// Intermediate States
+		s.zki.ISOnChain[s.i] = big.NewInt(1)
+	}
+
 	switch tx.Type {
 	case common.TxTypeForceTransfer, common.TxTypeTransfer:
 		// go to the MT account of sender and receiver, and update balance
@@ -116,6 +216,11 @@ func (s *StateDB) processL1Tx(exitTree *merkletree.MerkleTree, tx *common.L1Tx)
 		if err != nil {
 			return nil, nil, err
 		}
+
+		if s.zki != nil {
+			s.zki.AuxFromIdx[s.i] = s.idx.BigInt() // last s.idx is the one used for creating the new account
+			s.zki.NewAccount[s.i] = big.NewInt(1)
+		}
 	case common.TxTypeDeposit:
 		// update balance of the MT account
 		err := s.applyDeposit(tx, false)
@@ -140,6 +245,11 @@ func (s *StateDB) processL1Tx(exitTree *merkletree.MerkleTree, tx *common.L1Tx)
 		if err != nil {
 			return nil, nil, err
 		}
+
+		if s.zki != nil {
+			s.zki.AuxFromIdx[s.i] = s.idx.BigInt() // last s.idx is the one used for creating the new account
+			s.zki.NewAccount[s.i] = big.NewInt(1)
+		}
 	case common.TxTypeExit:
 		// execute exit flow
 		exitAccount, err := s.applyExit(exitTree, tx.Tx())
@@ -155,7 +265,48 @@ func (s *StateDB) processL1Tx(exitTree *merkletree.MerkleTree, tx *common.L1Tx)
 
 // processL2Tx process the given L2Tx applying the needed updates to
 // the StateDB depending on the transaction Type.
-func (s *StateDB) processL2Tx(exitTree *merkletree.MerkleTree, tx *common.L2Tx) (*common.Idx, *common.Account, error) {
+func (s *StateDB) processL2Tx(exitTree *merkletree.MerkleTree, tx *common.PoolL2Tx) (*common.Idx, *common.Account, error) {
+	// ZKInputs
+	if s.zki != nil {
+		// Txs
+		// s.zki.TxCompressedData[s.i] = tx.TxCompressedData() // uncomment once L1Tx.TxCompressedData is ready
+		// s.zki.TxCompressedDataV2[s.i] = tx.TxCompressedDataV2() // uncomment once L2Tx.TxCompressedDataV2 is ready
+		s.zki.FromIdx[s.i] = tx.FromIdx.BigInt()
+		s.zki.ToIdx[s.i] = tx.ToIdx.BigInt()
+
+		// fill AuxToIdx if needed
+		if tx.ToIdx == common.Idx(0) {
+			// Idx not set in the Tx, get it from DB through ToEthAddr or ToBJJ
+			var idx common.Idx
+			if !bytes.Equal(tx.ToEthAddr.Bytes(), ffAddr.Bytes()) {
+				idx = s.getIdxByEthAddr(tx.ToEthAddr)
+				if idx == common.Idx(0) {
+					return nil, nil, fmt.Errorf("Idx can not be found for given tx.FromEthAddr")
+				}
+			} else {
+				idx = s.getIdxByBJJ(tx.ToBJJ)
+				if idx == common.Idx(0) {
+					return nil, nil, fmt.Errorf("Idx can not be found for given tx.FromBJJ")
+				}
+			}
+			s.zki.AuxToIdx[s.i] = idx.BigInt()
+		}
+		s.zki.ToBJJAy[s.i] = tx.ToBJJ.Y
+		s.zki.ToEthAddr[s.i] = common.EthAddrToBigInt(tx.ToEthAddr)
+
+		s.zki.OnChain[s.i] = big.NewInt(0)
+		s.zki.NewAccount[s.i] = big.NewInt(0)
+
+		// L2Txs
+		// s.zki.RqOffset[s.i] =  // TODO
+		// s.zki.RqTxCompressedDataV2[s.i] = // TODO
+		// s.zki.RqToEthAddr[s.i] = common.EthAddrToBigInt(tx.RqToEthAddr) // TODO
+		// s.zki.RqToBJJAy[s.i] = tx.ToBJJ.Y // TODO
+		s.zki.S[s.i] = tx.Signature.S
+		s.zki.R8x[s.i] = tx.Signature.R8.X
+		s.zki.R8y[s.i] = tx.Signature.R8.Y
+	}
+
 	switch tx.Type {
 	case common.TxTypeTransfer:
 		// go to the MT account of sender and receiver, and update
diff --git a/db/statedb/txprocessors_test.go b/db/statedb/txprocessors_test.go
index 5a9dd06..3e95d92 100644
--- a/db/statedb/txprocessors_test.go
+++ b/db/statedb/txprocessors_test.go
@@ -1,6 +1,8 @@
 package statedb
 
 import (
+	"encoding/json"
+	"fmt"
 	"io/ioutil"
 	"strings"
 	"testing"
@@ -11,6 +13,8 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+var debug = false
+
 func TestProcessTxs(t *testing.T) {
 	dir, err := ioutil.TempDir("", "tmpdb")
 	require.Nil(t, err)
@@ -30,9 +34,9 @@ func TestProcessTxs(t *testing.T) {
 
 	// iterate for each batch
 	for i := 0; i < len(l1Txs); i++ {
-		l2Txs := common.PoolL2TxsToL2Txs(poolL2Txs[i])
+		// l2Txs := common.PoolL2TxsToL2Txs(poolL2Txs[i])
 
-		_, _, err := sdb.ProcessTxs(true, l1Txs[i], coordinatorL1Txs[i], l2Txs)
+		_, _, err := sdb.ProcessTxs(true, true, l1Txs[i], coordinatorL1Txs[i], poolL2Txs[i])
 		require.Nil(t, err)
 	}
 
@@ -65,8 +69,8 @@ func TestProcessTxsBatchByBatch(t *testing.T) {
 	assert.Equal(t, 7, len(poolL2Txs[2]))
 
 	// use first batch
-	l2txs := common.PoolL2TxsToL2Txs(poolL2Txs[0])
-	_, exitInfos, err := sdb.ProcessTxs(true, l1Txs[0], coordinatorL1Txs[0], l2txs)
+	// l2txs := common.PoolL2TxsToL2Txs(poolL2Txs[0])
+	_, exitInfos, err := sdb.ProcessTxs(true, true, l1Txs[0], coordinatorL1Txs[0], poolL2Txs[0])
 	require.Nil(t, err)
 	assert.Equal(t, 0, len(exitInfos))
 	acc, err := sdb.GetAccount(common.Idx(1))
@@ -74,8 +78,8 @@ func TestProcessTxsBatchByBatch(t *testing.T) {
 	assert.Equal(t, "28", acc.Balance.String())
 
 	// use second batch
-	l2txs = common.PoolL2TxsToL2Txs(poolL2Txs[1])
-	_, exitInfos, err = sdb.ProcessTxs(true, l1Txs[1], coordinatorL1Txs[1], l2txs)
+	// l2txs = common.PoolL2TxsToL2Txs(poolL2Txs[1])
+	_, exitInfos, err = sdb.ProcessTxs(true, true, l1Txs[1], coordinatorL1Txs[1], poolL2Txs[1])
 	require.Nil(t, err)
 	assert.Equal(t, 5, len(exitInfos))
 	acc, err = sdb.GetAccount(common.Idx(1))
@@ -83,11 +87,38 @@ func TestProcessTxsBatchByBatch(t *testing.T) {
 	assert.Equal(t, "48", acc.Balance.String())
 
 	// use third batch
-	l2txs = common.PoolL2TxsToL2Txs(poolL2Txs[2])
-	_, exitInfos, err = sdb.ProcessTxs(true, l1Txs[2], coordinatorL1Txs[2], l2txs)
+	// l2txs = common.PoolL2TxsToL2Txs(poolL2Txs[2])
+	_, exitInfos, err = sdb.ProcessTxs(true, true, l1Txs[2], coordinatorL1Txs[2], poolL2Txs[2])
 	require.Nil(t, err)
 	assert.Equal(t, 1, len(exitInfos))
 	acc, err = sdb.GetAccount(common.Idx(1))
 	assert.Nil(t, err)
 	assert.Equal(t, "23", acc.Balance.String())
 }
+
+func TestZKInputsGeneration(t *testing.T) {
+	dir, err := ioutil.TempDir("", "tmpdb")
+	require.Nil(t, err)
+
+	sdb, err := NewStateDB(dir, true, 32)
+	assert.Nil(t, err)
+
+	// generate test transactions from test.SetTest0 code
+	parser := test.NewParser(strings.NewReader(test.SetTest0))
+	instructions, err := parser.Parse()
+	assert.Nil(t, err)
+
+	l1Txs, coordinatorL1Txs, poolL2Txs := test.GenerateTestTxs(t, instructions)
+	assert.Equal(t, 29, len(l1Txs[0]))
+	assert.Equal(t, 0, len(coordinatorL1Txs[0]))
+	assert.Equal(t, 21, len(poolL2Txs[0]))
+
+	zki, _, err := sdb.ProcessTxs(false, true, l1Txs[0], coordinatorL1Txs[0], poolL2Txs[0])
+	require.Nil(t, err)
+
+	s, err := json.Marshal(zki)
+	require.Nil(t, err)
+	if debug {
+		fmt.Println(string(s))
+	}
+}
diff --git a/db/statedb/utils.go b/db/statedb/utils.go
new file mode 100644
index 0000000..ce46240
--- /dev/null
+++ b/db/statedb/utils.go
@@ -0,0 +1,17 @@
+package statedb
+
+import (
+	ethCommon "github.com/ethereum/go-ethereum/common"
+	"github.com/hermeznetwork/hermez-node/common"
+	"github.com/iden3/go-iden3-crypto/babyjub"
+)
+
+// TODO
+func (s *StateDB) getIdxByEthAddr(addr ethCommon.Address) common.Idx {
+	return common.Idx(0)
+}
+
+// TODO
+func (s *StateDB) getIdxByBJJ(pk *babyjub.PublicKey) common.Idx {
+	return common.Idx(0)
+}

From 69fe471f112da52b07ab2dc5f33f46c3259dcfb6 Mon Sep 17 00:00:00 2001
From: arnaucube <root@arnaucube.com>
Date: Wed, 9 Sep 2020 19:21:09 +0200
Subject: [PATCH 3/3] Add StateTree leafs & ExtTree data ZKI calculation

---
 common/pooll2tx.go                   |  25 +-
 common/utils.go                      |  18 --
 common/zk.go                         |  17 +-
 db/statedb/statedb.go                |   2 +-
 db/statedb/txprocessors.go           | 327 +++++++++++++++++++++------
 db/statedb/utils.go                  |  28 +++
 {common => db/statedb}/utils_test.go |   2 +-
 7 files changed, 316 insertions(+), 103 deletions(-)
 rename {common => db/statedb}/utils_test.go (97%)

diff --git a/common/pooll2tx.go b/common/pooll2tx.go
index 92009b6..04844b2 100644
--- a/common/pooll2tx.go
+++ b/common/pooll2tx.go
@@ -27,6 +27,11 @@ func (n Nonce) Bytes() ([5]byte, error) {
 	return b, nil
 }
 
+// BigInt returns the *big.Int representation of the Nonce value
+func (n Nonce) BigInt() *big.Int {
+	return big.NewInt(int64(n))
+}
+
 // NonceFromBytes returns Nonce from a [5]byte
 func NonceFromBytes(b [5]byte) Nonce {
 	var nonceBytes [8]byte
@@ -76,7 +81,7 @@ type PoolL2Tx struct {
 // [ 32 bits ] tokenID // 4 bytes: [20:24]
 // [ 40 bits ] nonce // 5 bytes: [24:29]
 // [ 8 bits  ] userFee // 1 byte: [29:30]
-// [ 1 bits  ] toBjjSign // 1 byte: [30:31]
+// [ 1 bits  ] toBJJSign // 1 byte: [30:31]
 // Total bits compressed data:  241 bits // 31 bytes in *big.Int representation
 func (tx *PoolL2Tx) TxCompressedData() (*big.Int, error) {
 	// sigconstant
@@ -102,11 +107,11 @@ func (tx *PoolL2Tx) TxCompressedData() (*big.Int, error) {
 	}
 	copy(b[24:29], nonceBytes[:])
 	b[29] = byte(tx.Fee)
-	toBjjSign := byte(0)
+	toBJJSign := byte(0)
 	if babyjub.PointCoordSign(tx.ToBJJ.X) {
-		toBjjSign = byte(1)
+		toBJJSign = byte(1)
 	}
-	b[30] = toBjjSign
+	b[30] = toBJJSign
 	bi := new(big.Int).SetBytes(SwapEndianness(b[:]))
 
 	return bi, nil
@@ -119,7 +124,7 @@ func (tx *PoolL2Tx) TxCompressedData() (*big.Int, error) {
 // [ 32 bits ] tokenID // 4 bytes: [14:18]
 // [ 40 bits ] nonce // 5 bytes: [18:23]
 // [ 8 bits  ] userFee // 1 byte: [23:24]
-// [ 1 bits  ] toBjjSign // 1 byte: [24:25]
+// [ 1 bits  ] toBJJSign // 1 byte: [24:25]
 // Total bits compressed data:  193 bits // 25 bytes in *big.Int representation
 func (tx *PoolL2Tx) TxCompressedDataV2() (*big.Int, error) {
 	amountFloat16, err := utils.NewFloat16(tx.Amount)
@@ -137,11 +142,11 @@ func (tx *PoolL2Tx) TxCompressedDataV2() (*big.Int, error) {
 	}
 	copy(b[18:23], nonceBytes[:])
 	b[23] = byte(tx.Fee)
-	toBjjSign := byte(0)
+	toBJJSign := byte(0)
 	if babyjub.PointCoordSign(tx.ToBJJ.X) {
-		toBjjSign = byte(1)
+		toBJJSign = byte(1)
 	}
-	b[24] = toBjjSign
+	b[24] = toBJJSign
 
 	bi := new(big.Int).SetBytes(SwapEndianness(b[:]))
 	return bi, nil
@@ -154,13 +159,13 @@ func (tx *PoolL2Tx) HashToSign() (*big.Int, error) {
 		return nil, err
 	}
 	toEthAddr := EthAddrToBigInt(tx.ToEthAddr)
-	toBjjAy := tx.ToBJJ.Y
+	toBJJAy := tx.ToBJJ.Y
 	rqTxCompressedDataV2, err := tx.TxCompressedDataV2()
 	if err != nil {
 		return nil, err
 	}
 
-	return poseidon.Hash([]*big.Int{toCompressedData, toEthAddr, toBjjAy, rqTxCompressedDataV2, EthAddrToBigInt(tx.RqToEthAddr), tx.RqToBJJ.Y})
+	return poseidon.Hash([]*big.Int{toCompressedData, toEthAddr, toBJJAy, rqTxCompressedDataV2, EthAddrToBigInt(tx.RqToEthAddr), tx.RqToBJJ.Y})
 }
 
 // VerifySignature returns true if the signature verification is correct for the given PublicKey
diff --git a/common/utils.go b/common/utils.go
index 3ec26be..9dad220 100644
--- a/common/utils.go
+++ b/common/utils.go
@@ -4,7 +4,6 @@ import (
 	"math/big"
 
 	ethCommon "github.com/ethereum/go-ethereum/common"
-	"github.com/iden3/go-iden3-crypto/babyjub"
 )
 
 // SwapEndianness swaps the order of the bytes in the slice.
@@ -20,20 +19,3 @@ func SwapEndianness(b []byte) []byte {
 func EthAddrToBigInt(a ethCommon.Address) *big.Int {
 	return new(big.Int).SetBytes(a.Bytes())
 }
-
-// BJJCompressedTo256BigInts returns a [256]*big.Int array with the bit
-// representation of the babyjub.PublicKeyComp
-func BJJCompressedTo256BigInts(pkComp babyjub.PublicKeyComp) [256]*big.Int {
-	var r [256]*big.Int
-	b := pkComp[:]
-
-	for i := 0; i < 256; i++ {
-		if b[i/8]&(1<<(i%8)) == 0 {
-			r[i] = big.NewInt(0)
-		} else {
-			r[i] = big.NewInt(1)
-		}
-	}
-
-	return r
-}
diff --git a/common/zk.go b/common/zk.go
index 1b7d378..4becfbd 100644
--- a/common/zk.go
+++ b/common/zk.go
@@ -64,13 +64,12 @@ type ZKInputs struct {
 
 	// OnChain determines if is L1 (1/true) or L2 (0/false)
 	OnChain []*big.Int // bool, len: [nTx]
-	// NewAccount boolean (0/1) flag set 'true' when L1 tx creates a new account (fromIdx==0)
-	NewAccount []*big.Int // bool, len: [nTx]
 
 	//
 	// Txs/L1Txs
 	//
-	// transaction L1
+	// NewAccount boolean (0/1) flag set 'true' when L1 tx creates a new account (fromIdx==0)
+	NewAccount []*big.Int // bool, len: [nTx]
 	// LoadAmountF encoded as float16
 	LoadAmountF []*big.Int // uint16, len: [nTx]
 	// FromEthAddr
@@ -109,8 +108,8 @@ type ZKInputs struct {
 	TokenID1  []*big.Int   // uint32, len: [nTx]
 	Nonce1    []*big.Int   // uint64 (max 40 bits), len: [nTx]
 	Sign1     []*big.Int   // bool, len: [nTx]
-	Balance1  []*big.Int   // big.Int (max 192 bits), len: [nTx]
 	Ay1       []*big.Int   // big.Int, len: [nTx]
+	Balance1  []*big.Int   // big.Int (max 192 bits), len: [nTx]
 	EthAddr1  []*big.Int   // ethCommon.Address, len: [nTx]
 	Siblings1 [][]*big.Int // big.Int, len: [nTx][nLevels + 1]
 	// Required for inserts and deletes, values of the CircomProcessorProof (smt insert proof)
@@ -123,8 +122,8 @@ type ZKInputs struct {
 	TokenID2  []*big.Int   // uint32, len: [nTx]
 	Nonce2    []*big.Int   // uint64 (max 40 bits), len: [nTx]
 	Sign2     []*big.Int   // bool, len: [nTx]
-	Balance2  []*big.Int   // big.Int (max 192 bits), len: [nTx]
 	Ay2       []*big.Int   // big.Int, len: [nTx]
+	Balance2  []*big.Int   // big.Int (max 192 bits), len: [nTx]
 	EthAddr2  []*big.Int   // ethCommon.Address, len: [nTx]
 	Siblings2 [][]*big.Int // big.Int, len: [nTx][nLevels + 1]
 	// newExit determines if an exit transaction has to create a new leaf in the exit tree
@@ -140,8 +139,8 @@ type ZKInputs struct {
 	TokenID3  []*big.Int   // uint32, len: [maxFeeTx]
 	Nonce3    []*big.Int   // uint64 (max 40 bits), len: [maxFeeTx]
 	Sign3     []*big.Int   // bool, len: [maxFeeTx]
-	Balance3  []*big.Int   // big.Int (max 192 bits), len: [maxFeeTx]
 	Ay3       []*big.Int   // big.Int, len: [maxFeeTx]
+	Balance3  []*big.Int   // big.Int (max 192 bits), len: [maxFeeTx]
 	EthAddr3  []*big.Int   // ethCommon.Address, len: [maxFeeTx]
 	Siblings3 [][]*big.Int // Hash, len: [maxFeeTx][nLevels + 1]
 
@@ -218,8 +217,8 @@ func NewZKInputs(nTx, maxFeeTx, nLevels int) *ZKInputs {
 	zki.TokenID1 = newSlice(nTx)
 	zki.Nonce1 = newSlice(nTx)
 	zki.Sign1 = newSlice(nTx)
-	zki.Balance1 = newSlice(nTx)
 	zki.Ay1 = newSlice(nTx)
+	zki.Balance1 = newSlice(nTx)
 	zki.EthAddr1 = newSlice(nTx)
 	zki.Siblings1 = make([][]*big.Int, nTx)
 	for i := 0; i < len(zki.Siblings1); i++ {
@@ -232,8 +231,8 @@ func NewZKInputs(nTx, maxFeeTx, nLevels int) *ZKInputs {
 	zki.TokenID2 = newSlice(nTx)
 	zki.Nonce2 = newSlice(nTx)
 	zki.Sign2 = newSlice(nTx)
-	zki.Balance2 = newSlice(nTx)
 	zki.Ay2 = newSlice(nTx)
+	zki.Balance2 = newSlice(nTx)
 	zki.EthAddr2 = newSlice(nTx)
 	zki.Siblings2 = make([][]*big.Int, nTx)
 	for i := 0; i < len(zki.Siblings2); i++ {
@@ -247,8 +246,8 @@ func NewZKInputs(nTx, maxFeeTx, nLevels int) *ZKInputs {
 	zki.TokenID3 = newSlice(maxFeeTx)
 	zki.Nonce3 = newSlice(maxFeeTx)
 	zki.Sign3 = newSlice(maxFeeTx)
-	zki.Balance3 = newSlice(maxFeeTx)
 	zki.Ay3 = newSlice(maxFeeTx)
+	zki.Balance3 = newSlice(maxFeeTx)
 	zki.EthAddr3 = newSlice(maxFeeTx)
 	zki.Siblings3 = make([][]*big.Int, maxFeeTx)
 	for i := 0; i < len(zki.Siblings3); i++ {
diff --git a/db/statedb/statedb.go b/db/statedb/statedb.go
index e5e83ff..008e8b0 100644
--- a/db/statedb/statedb.go
+++ b/db/statedb/statedb.go
@@ -44,7 +44,7 @@ type StateDB struct {
 	// idx holds the current Idx that the BatchBuilder is using
 	idx common.Idx
 	zki *common.ZKInputs
-	i   int // i is used for zki
+	i   int // i is the current transaction index in the ZKInputs generation (zki)
 }
 
 // NewStateDB creates a new StateDB, allowing to use an in-memory or in-disk
diff --git a/db/statedb/txprocessors.go b/db/statedb/txprocessors.go
index d3ea768..368c444 100644
--- a/db/statedb/txprocessors.go
+++ b/db/statedb/txprocessors.go
@@ -8,6 +8,8 @@ import (
 
 	ethCommon "github.com/ethereum/go-ethereum/common"
 	"github.com/hermeznetwork/hermez-node/common"
+	"github.com/hermeznetwork/hermez-node/log"
+	"github.com/iden3/go-iden3-crypto/babyjub"
 	"github.com/iden3/go-iden3-crypto/poseidon"
 	"github.com/iden3/go-merkletree"
 	"github.com/iden3/go-merkletree/db"
@@ -26,6 +28,13 @@ func (s *StateDB) resetZKInputs() {
 	s.i = 0
 }
 
+type processedExit struct {
+	exit    bool
+	newExit bool
+	idx     common.Idx
+	acc     common.Account
+}
+
 // ProcessTxs process the given L1Txs & L2Txs applying the needed updates to
 // the StateDB depending on the transaction Type. Returns the common.ZKInputs
 // to generate the SnarkProof later used by the BatchBuilder, and if
@@ -34,20 +43,23 @@ func (s *StateDB) resetZKInputs() {
 func (s *StateDB) ProcessTxs(cmpExitTree, cmpZKInputs bool, l1usertxs, l1coordinatortxs []*common.L1Tx, l2txs []*common.PoolL2Tx) (*common.ZKInputs, []*common.ExitInfo, error) {
 	var err error
 	var exitTree *merkletree.MerkleTree
-	exits := make(map[common.Idx]common.Account)
 
 	if s.zki != nil {
-		return nil, nil, errors.New("Expected StateDB.zki==nil, something went wrong ans is not empty")
+		return nil, nil, errors.New("Expected StateDB.zki==nil, something went wrong and it's not empty")
 	}
 	defer s.resetZKInputs()
 
 	nTx := len(l1usertxs) + len(l1coordinatortxs) + len(l2txs)
 	if nTx == 0 {
-		return nil, nil, nil // TBD if return an error in the case of no Txs to process
+		// TODO return ZKInputs of batch without txs
+		return nil, nil, nil
 	}
+	exits := make([]processedExit, nTx)
 
 	if cmpZKInputs {
-		s.zki = common.NewZKInputs(nTx, 24, 32) // TODO this values will be parameters of the function
+		s.zki = common.NewZKInputs(nTx, 24, 32) // TODO this values will be parameters of the function, taken from config file/coordinator call
+		s.zki.OldLastIdx = (s.idx - 1).BigInt()
+		s.zki.OldStateRoot = s.mt.Root().BigInt()
 	}
 
 	// TBD if ExitTree is only in memory or stored in disk, for the moment
@@ -59,36 +71,54 @@ func (s *StateDB) ProcessTxs(cmpExitTree, cmpZKInputs bool, l1usertxs, l1coordin
 
 	// assumption: l1usertx are sorted by L1Tx.Position
 	for _, tx := range l1usertxs {
-		exitIdx, exitAccount, err := s.processL1Tx(exitTree, tx)
+		exitIdx, exitAccount, newExit, err := s.processL1Tx(exitTree, tx)
 		if err != nil {
 			return nil, nil, err
 		}
 		if exitIdx != nil && cmpExitTree {
-			exits[*exitIdx] = *exitAccount
+			exits[s.i] = processedExit{
+				exit:    true,
+				newExit: newExit,
+				idx:     *exitIdx,
+				acc:     *exitAccount,
+			}
 		}
 		if s.zki != nil {
 			s.i++
 		}
 	}
 	for _, tx := range l1coordinatortxs {
-		exitIdx, exitAccount, err := s.processL1Tx(exitTree, tx)
+		exitIdx, exitAccount, newExit, err := s.processL1Tx(exitTree, tx)
 		if err != nil {
 			return nil, nil, err
 		}
+		if exitIdx != nil {
+			log.Error("Unexpected Exit in L1CoordinatorTx")
+		}
 		if exitIdx != nil && cmpExitTree {
-			exits[*exitIdx] = *exitAccount
+			exits[s.i] = processedExit{
+				exit:    true,
+				newExit: newExit,
+				idx:     *exitIdx,
+				acc:     *exitAccount,
+			}
 		}
 		if s.zki != nil {
 			s.i++
 		}
 	}
 	for _, tx := range l2txs {
-		exitIdx, exitAccount, err := s.processL2Tx(exitTree, tx)
+		exitIdx, exitAccount, newExit, err := s.processL2Tx(exitTree, tx)
 		if err != nil {
 			return nil, nil, err
 		}
 		if exitIdx != nil && cmpExitTree {
-			exits[*exitIdx] = *exitAccount
+			exits[s.i] = processedExit{
+				exit:    true,
+				newExit: newExit,
+				idx:     *exitIdx,
+				acc:     *exitAccount,
+			}
 		}
 		if s.zki != nil {
 			s.i++
@@ -99,10 +129,16 @@ func (s *StateDB) ProcessTxs(cmpExitTree, cmpZKInputs bool, l1usertxs, l1coordin
 		return nil, nil, nil
 	}
 
-	// once all txs processed (exitTree root frozen), for each leaf
+	// once all txs processed (exitTree root frozen), for each Exit,
 	// generate common.ExitInfo data
 	var exitInfos []*common.ExitInfo
-	for exitIdx, exitAccount := range exits {
+	for i := 0; i < nTx; i++ {
+		if !exits[i].exit {
+			continue
+		}
+		exitIdx := exits[i].idx
+		exitAccount := exits[i].acc
+
 		// 0. generate MerkleProof
 		p, err := exitTree.GenerateCircomVerifierProof(exitIdx.BigInt(), nil)
 		if err != nil {
@@ -129,15 +165,33 @@ func (s *StateDB) ProcessTxs(cmpExitTree, cmpZKInputs bool, l1usertxs, l1coordin
 			Balance:     exitAccount.Balance,
 		}
 		exitInfos = append(exitInfos, ei)
+
+		if s.zki != nil {
+			s.zki.TokenID2[i] = exitAccount.TokenID.BigInt()
+			s.zki.Nonce2[i] = exitAccount.Nonce.BigInt()
+			if babyjub.PointCoordSign(exitAccount.PublicKey.X) {
+				s.zki.Sign2[i] = big.NewInt(1)
+			}
+			s.zki.Ay2[i] = exitAccount.PublicKey.Y
+			s.zki.Balance2[i] = exitAccount.Balance
+			s.zki.EthAddr2[i] = common.EthAddrToBigInt(exitAccount.EthAddr)
+			s.zki.Siblings2[i] = p.Siblings
+			if exits[i].newExit {
+				s.zki.NewExit[i] = big.NewInt(1)
+			}
+			if p.IsOld0 {
+				s.zki.IsOld0_2[i] = big.NewInt(1)
+			}
+			s.zki.OldKey2[i] = p.OldKey.BigInt()
+			s.zki.OldValue2[i] = p.OldValue.BigInt()
+		}
 	}
 	if !cmpZKInputs {
 		return nil, exitInfos, nil
 	}
 
 	// compute last ZKInputs parameters
-	s.zki.OldLastIdx = (s.idx - 1).BigInt()
-	s.zki.OldStateRoot = s.mt.Root().BigInt()
-	s.zki.GlobalChainID = big.NewInt(0) // TODO, 0: ethereum, get this from config file
+	s.zki.GlobalChainID = big.NewInt(0) // TODO, 0: ethereum, this will be get from config file
 	// zki.FeeIdxs = ? // TODO, this will be get from the config file
 	tokenIDs, err := s.getTokenIDsBigInt(l1usertxs, l1coordinatortxs, l2txs)
 	if err != nil {
@@ -146,9 +200,9 @@ func (s *StateDB) ProcessTxs(cmpExitTree, cmpZKInputs bool, l1usertxs, l1coordin
 	s.zki.FeePlanTokens = tokenIDs
 
 	// s.zki.ISInitStateRootFee = s.mt.Root().BigInt()
-	// compute fees
 
-	// once fees are computed
+	// TODO once the Node Config sets the Accounts where to send the Fees
+	// compute fees & update ZKInputs
 
 	// return exitInfos, so Synchronizer will be able to store it into
 	// HistoryDB for the concrete BatchNum
@@ -181,8 +235,10 @@ func (s *StateDB) getTokenIDsBigInt(l1usertxs, l1coordinatortxs []*common.L1Tx,
 }
 
 // processL1Tx process the given L1Tx applying the needed updates to the
-// StateDB depending on the transaction Type.
-func (s *StateDB) processL1Tx(exitTree *merkletree.MerkleTree, tx *common.L1Tx) (*common.Idx, *common.Account, error) {
+// StateDB depending on the transaction Type. It returns the 3 parameters
+// related to the Exit (in case of): Idx, ExitAccount, boolean determining if
+// the Exit created a new Leaf in the ExitTree.
+func (s *StateDB) processL1Tx(exitTree *merkletree.MerkleTree, tx *common.L1Tx) (*common.Idx, *common.Account, bool, error) {
 	// ZKInputs
 	if s.zki != nil {
 		// Txs
@@ -195,7 +251,7 @@ func (s *StateDB) processL1Tx(exitTree *merkletree.MerkleTree, tx *common.L1Tx)
 		s.zki.LoadAmountF[s.i] = tx.LoadAmount
 		s.zki.FromEthAddr[s.i] = common.EthAddrToBigInt(tx.FromEthAddr)
 		if tx.FromBJJ != nil {
-			s.zki.FromBJJCompressed[s.i] = common.BJJCompressedTo256BigInts(tx.FromBJJ.Compress())
+			s.zki.FromBJJCompressed[s.i] = BJJCompressedTo256BigInts(tx.FromBJJ.Compress())
 		}
 
 		// Intermediate States
@@ -208,13 +264,13 @@ func (s *StateDB) processL1Tx(exitTree *merkletree.MerkleTree, tx *common.L1Tx)
 		// & nonce
 		err := s.applyTransfer(tx.Tx())
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, false, err
 		}
 	case common.TxTypeCreateAccountDeposit:
 		// add new account to the MT, update balance of the MT account
 		err := s.applyCreateAccount(tx)
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, false, err
 		}
 
 		if s.zki != nil {
@@ -225,25 +281,21 @@ func (s *StateDB) processL1Tx(exitTree *merkletree.MerkleTree, tx *common.L1Tx)
 		// update balance of the MT account
 		err := s.applyDeposit(tx, false)
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, false, err
 		}
 	case common.TxTypeDepositTransfer:
 		// update balance in MT account, update balance & nonce of sender
 		// & receiver
 		err := s.applyDeposit(tx, true)
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, false, err
 		}
 	case common.TxTypeCreateAccountDepositTransfer:
 		// add new account to the merkletree, update balance in MT account,
 		// update balance & nonce of sender & receiver
-		err := s.applyCreateAccount(tx)
-		if err != nil {
-			return nil, nil, err
-		}
-		err = s.applyTransfer(tx.Tx())
+		err := s.applyCreateAccountDepositTransfer(tx)
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, false, err
 		}
 
 		if s.zki != nil {
@@ -252,20 +304,22 @@ func (s *StateDB) processL1Tx(exitTree *merkletree.MerkleTree, tx *common.L1Tx)
 		}
 	case common.TxTypeExit:
 		// execute exit flow
-		exitAccount, err := s.applyExit(exitTree, tx.Tx())
+		exitAccount, newExit, err := s.applyExit(exitTree, tx.Tx())
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, false, err
 		}
-		return &tx.FromIdx, exitAccount, nil
+		return &tx.FromIdx, exitAccount, newExit, nil
 	default:
 	}
 
-	return nil, nil, nil
+	return nil, nil, false, nil
 }
 
-// processL2Tx process the given L2Tx applying the needed updates to
-// the StateDB depending on the transaction Type.
-func (s *StateDB) processL2Tx(exitTree *merkletree.MerkleTree, tx *common.PoolL2Tx) (*common.Idx, *common.Account, error) {
+// processL2Tx process the given L2Tx applying the needed updates to the
+// StateDB depending on the transaction Type. It returns the 3 parameters
+// related to the Exit (in case of): Idx, ExitAccount, boolean determining if
+// the Exit created a new Leaf in the ExitTree.
+func (s *StateDB) processL2Tx(exitTree *merkletree.MerkleTree, tx *common.PoolL2Tx) (*common.Idx, *common.Account, bool, error) {
 	// ZKInputs
 	if s.zki != nil {
 		// Txs
@@ -281,12 +335,12 @@ func (s *StateDB) processL2Tx(exitTree *merkletree.MerkleTree, tx *common.PoolL2
 			if !bytes.Equal(tx.ToEthAddr.Bytes(), ffAddr.Bytes()) {
 				idx = s.getIdxByEthAddr(tx.ToEthAddr)
 				if idx == common.Idx(0) {
-					return nil, nil, fmt.Errorf("Idx can not be found for given tx.FromEthAddr")
+					return nil, nil, false, fmt.Errorf("Idx can not be found for given tx.FromEthAddr")
 				}
 			} else {
 				idx = s.getIdxByBJJ(tx.ToBJJ)
 				if idx == common.Idx(0) {
-					return nil, nil, fmt.Errorf("Idx can not be found for given tx.FromBJJ")
+					return nil, nil, false, fmt.Errorf("Idx can not be found for given tx.FromBJJ")
 				}
 			}
 			s.zki.AuxToIdx[s.i] = idx.BigInt()
@@ -298,7 +352,7 @@ func (s *StateDB) processL2Tx(exitTree *merkletree.MerkleTree, tx *common.PoolL2
 		s.zki.NewAccount[s.i] = big.NewInt(0)
 
 		// L2Txs
-		// s.zki.RqOffset[s.i] =  // TODO
+		// s.zki.RqOffset[s.i] =  // TODO Rq once TxSelector is ready
 		// s.zki.RqTxCompressedDataV2[s.i] = // TODO
 		// s.zki.RqToEthAddr[s.i] = common.EthAddrToBigInt(tx.RqToEthAddr) // TODO
 		// s.zki.RqToBJJAy[s.i] = tx.ToBJJ.Y // TODO
@@ -313,18 +367,18 @@ func (s *StateDB) processL2Tx(exitTree *merkletree.MerkleTree, tx *common.PoolL2
 		// balance & nonce
 		err := s.applyTransfer(tx.Tx())
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, false, err
 		}
 	case common.TxTypeExit:
 		// execute exit flow
-		exitAccount, err := s.applyExit(exitTree, tx.Tx())
+		exitAccount, newExit, err := s.applyExit(exitTree, tx.Tx())
 		if err != nil {
-			return nil, nil, err
+			return nil, nil, false, err
 		}
-		return &tx.FromIdx, exitAccount, nil
+		return &tx.FromIdx, exitAccount, newExit, nil
 	default:
 	}
-	return nil, nil, nil
+	return nil, nil, false, nil
 }
 
 // applyCreateAccount creates a new account in the account of the depositer, it
@@ -338,10 +392,26 @@ func (s *StateDB) applyCreateAccount(tx *common.L1Tx) error {
 		EthAddr:   tx.FromEthAddr,
 	}
 
-	_, err := s.CreateAccount(common.Idx(s.idx+1), account)
+	p, err := s.CreateAccount(common.Idx(s.idx+1), account)
 	if err != nil {
 		return err
 	}
+	if s.zki != nil {
+		s.zki.TokenID1[s.i] = tx.TokenID.BigInt()
+		s.zki.Nonce1[s.i] = big.NewInt(0)
+		if babyjub.PointCoordSign(tx.FromBJJ.X) {
+			s.zki.Sign1[s.i] = big.NewInt(1)
+		}
+		s.zki.Ay1[s.i] = tx.FromBJJ.Y
+		s.zki.Balance1[s.i] = tx.LoadAmount
+		s.zki.EthAddr1[s.i] = common.EthAddrToBigInt(tx.FromEthAddr)
+		s.zki.Siblings1[s.i] = siblingsToZKInputFormat(p.Siblings)
+		if p.IsOld0 {
+			s.zki.IsOld0_1[s.i] = big.NewInt(1)
+		}
+		s.zki.OldKey1[s.i] = p.OldKey.BigInt()
+		s.zki.OldValue1[s.i] = p.OldValue.BigInt()
+	}
 
 	s.idx = s.idx + 1
 	return s.setIdx(s.idx)
@@ -359,8 +429,9 @@ func (s *StateDB) applyDeposit(tx *common.L1Tx, transfer bool) error {
 	accSender.Balance = new(big.Int).Add(accSender.Balance, tx.LoadAmount)
 
 	// in case that the tx is a L1Tx>DepositTransfer
+	var accReceiver *common.Account
 	if transfer {
-		accReceiver, err := s.GetAccount(tx.ToIdx)
+		accReceiver, err = s.GetAccount(tx.ToIdx)
 		if err != nil {
 			return err
 		}
@@ -368,17 +439,46 @@ func (s *StateDB) applyDeposit(tx *common.L1Tx, transfer bool) error {
 		accSender.Balance = new(big.Int).Sub(accSender.Balance, tx.Amount)
 		// add amount to the receiver
 		accReceiver.Balance = new(big.Int).Add(accReceiver.Balance, tx.Amount)
-		// update receiver account in localStateDB
-		_, err = s.UpdateAccount(tx.ToIdx, accReceiver)
-		if err != nil {
-			return err
-		}
 	}
 	// update sender account in localStateDB
-	_, err = s.UpdateAccount(tx.FromIdx, accSender)
+	p, err := s.UpdateAccount(tx.FromIdx, accSender)
 	if err != nil {
 		return err
 	}
+	if s.zki != nil {
+		s.zki.TokenID1[s.i] = accSender.TokenID.BigInt()
+		s.zki.Nonce1[s.i] = accSender.Nonce.BigInt()
+		if babyjub.PointCoordSign(accSender.PublicKey.X) {
+			s.zki.Sign1[s.i] = big.NewInt(1)
+		}
+		s.zki.Ay1[s.i] = accSender.PublicKey.Y
+		s.zki.Balance1[s.i] = accSender.Balance
+		s.zki.EthAddr1[s.i] = common.EthAddrToBigInt(accSender.EthAddr)
+		s.zki.Siblings1[s.i] = siblingsToZKInputFormat(p.Siblings)
+		// IsOld0_1, OldKey1, OldValue1 not needed as this is not an insert
+	}
+
+	// this is done after updating Sender Account (depositer)
+	if transfer {
+		// update receiver account in localStateDB
+		p, err := s.UpdateAccount(tx.ToIdx, accReceiver)
+		if err != nil {
+			return err
+		}
+		if s.zki != nil {
+			s.zki.TokenID2[s.i] = accReceiver.TokenID.BigInt()
+			s.zki.Nonce2[s.i] = accReceiver.Nonce.BigInt()
+			if babyjub.PointCoordSign(accReceiver.PublicKey.X) {
+				s.zki.Sign2[s.i] = big.NewInt(1)
+			}
+			s.zki.Ay2[s.i] = accReceiver.PublicKey.Y
+			s.zki.Balance2[s.i] = accReceiver.Balance
+			s.zki.EthAddr2[s.i] = common.EthAddrToBigInt(accReceiver.EthAddr)
+			s.zki.Siblings2[s.i] = siblingsToZKInputFormat(p.Siblings)
+			// IsOld0_2, OldKey2, OldValue2 not needed as this is not an insert
+		}
+	}
+
 	return nil
 }
 
@@ -403,31 +503,130 @@ func (s *StateDB) applyTransfer(tx *common.Tx) error {
 	// add amount to the receiver
 	accReceiver.Balance = new(big.Int).Add(accReceiver.Balance, tx.Amount)
 
-	// update receiver account in localStateDB
-	_, err = s.UpdateAccount(tx.ToIdx, accReceiver)
+	// update sender account in localStateDB
+	pSender, err := s.UpdateAccount(tx.FromIdx, accSender)
 	if err != nil {
 		return err
 	}
-	// update sender account in localStateDB
-	_, err = s.UpdateAccount(tx.FromIdx, accSender)
+	if s.zki != nil {
+		s.zki.TokenID1[s.i] = accSender.TokenID.BigInt()
+		s.zki.Nonce1[s.i] = accSender.Nonce.BigInt()
+		if babyjub.PointCoordSign(accSender.PublicKey.X) {
+			s.zki.Sign1[s.i] = big.NewInt(1)
+		}
+		s.zki.Ay1[s.i] = accSender.PublicKey.Y
+		s.zki.Balance1[s.i] = accSender.Balance
+		s.zki.EthAddr1[s.i] = common.EthAddrToBigInt(accSender.EthAddr)
+		s.zki.Siblings1[s.i] = siblingsToZKInputFormat(pSender.Siblings)
+	}
+
+	// update receiver account in localStateDB
+	pReceiver, err := s.UpdateAccount(tx.ToIdx, accReceiver)
 	if err != nil {
 		return err
 	}
+	if s.zki != nil {
+		s.zki.TokenID2[s.i] = accReceiver.TokenID.BigInt()
+		s.zki.Nonce2[s.i] = accReceiver.Nonce.BigInt()
+		if babyjub.PointCoordSign(accReceiver.PublicKey.X) {
+			s.zki.Sign2[s.i] = big.NewInt(1)
+		}
+		s.zki.Ay2[s.i] = accReceiver.PublicKey.Y
+		s.zki.Balance2[s.i] = accReceiver.Balance
+		s.zki.EthAddr2[s.i] = common.EthAddrToBigInt(accReceiver.EthAddr)
+		s.zki.Siblings2[s.i] = siblingsToZKInputFormat(pReceiver.Siblings)
+	}
 
 	return nil
 }
 
-func (s *StateDB) applyExit(exitTree *merkletree.MerkleTree, tx *common.Tx) (*common.Account, error) {
+// applyCreateAccountDepositTransfer, in a single tx, creates a new account,
+// makes a deposit, and performs a transfer to another account
+func (s *StateDB) applyCreateAccountDepositTransfer(tx *common.L1Tx) error {
+	accSender := &common.Account{
+		TokenID:   tx.TokenID,
+		Nonce:     0,
+		Balance:   tx.LoadAmount,
+		PublicKey: tx.FromBJJ,
+		EthAddr:   tx.FromEthAddr,
+	}
+	accSender.Balance = new(big.Int).Add(accSender.Balance, tx.LoadAmount)
+	accReceiver, err := s.GetAccount(tx.ToIdx)
+	if err != nil {
+		return err
+	}
+	// subtract amount to the sender
+	accSender.Balance = new(big.Int).Sub(accSender.Balance, tx.Amount)
+	// add amount to the receiver
+	accReceiver.Balance = new(big.Int).Add(accReceiver.Balance, tx.Amount)
+
+	// create Account of the Sender
+	p, err := s.CreateAccount(common.Idx(s.idx+1), accSender)
+	if err != nil {
+		return err
+	}
+	if s.zki != nil {
+		s.zki.TokenID1[s.i] = tx.TokenID.BigInt()
+		s.zki.Nonce1[s.i] = big.NewInt(0)
+		if babyjub.PointCoordSign(tx.FromBJJ.X) {
+			s.zki.Sign1[s.i] = big.NewInt(1)
+		}
+		s.zki.Ay1[s.i] = tx.FromBJJ.Y
+		s.zki.Balance1[s.i] = tx.LoadAmount
+		s.zki.EthAddr1[s.i] = common.EthAddrToBigInt(tx.FromEthAddr)
+		s.zki.Siblings1[s.i] = siblingsToZKInputFormat(p.Siblings)
+		if p.IsOld0 {
+			s.zki.IsOld0_1[s.i] = big.NewInt(1)
+		}
+		s.zki.OldKey1[s.i] = p.OldKey.BigInt()
+		s.zki.OldValue1[s.i] = p.OldValue.BigInt()
+	}
+
+	// update receiver account in localStateDB
+	p, err = s.UpdateAccount(tx.ToIdx, accReceiver)
+	if err != nil {
+		return err
+	}
+	if s.zki != nil {
+		s.zki.TokenID2[s.i] = accReceiver.TokenID.BigInt()
+		s.zki.Nonce2[s.i] = accReceiver.Nonce.BigInt()
+		if babyjub.PointCoordSign(accReceiver.PublicKey.X) {
+			s.zki.Sign2[s.i] = big.NewInt(1)
+		}
+		s.zki.Ay2[s.i] = accReceiver.PublicKey.Y
+		s.zki.Balance2[s.i] = accReceiver.Balance
+		s.zki.EthAddr2[s.i] = common.EthAddrToBigInt(accReceiver.EthAddr)
+		s.zki.Siblings2[s.i] = siblingsToZKInputFormat(p.Siblings)
+	}
+
+	s.idx = s.idx + 1
+	return s.setIdx(s.idx)
+}
+
+// It returns the ExitAccount and a boolean determining if the Exit created a
+// new Leaf in the ExitTree.
+func (s *StateDB) applyExit(exitTree *merkletree.MerkleTree, tx *common.Tx) (*common.Account, bool, error) {
 	// 0. subtract tx.Amount from current Account in StateMT
 	// add the tx.Amount into the Account (tx.FromIdx) in the ExitMT
 	acc, err := s.GetAccount(tx.FromIdx)
 	if err != nil {
-		return nil, err
+		return nil, false, err
 	}
 	acc.Balance = new(big.Int).Sub(acc.Balance, tx.Amount)
-	_, err = s.UpdateAccount(tx.FromIdx, acc)
+	p, err := s.UpdateAccount(tx.FromIdx, acc)
 	if err != nil {
-		return nil, err
+		return nil, false, err
+	}
+	if s.zki != nil {
+		s.zki.TokenID1[s.i] = acc.TokenID.BigInt()
+		s.zki.Nonce1[s.i] = acc.Nonce.BigInt()
+		if babyjub.PointCoordSign(acc.PublicKey.X) {
+			s.zki.Sign1[s.i] = big.NewInt(1)
+		}
+		s.zki.Ay1[s.i] = acc.PublicKey.Y
+		s.zki.Balance1[s.i] = acc.Balance
+		s.zki.EthAddr1[s.i] = common.EthAddrToBigInt(acc.EthAddr)
+		s.zki.Siblings1[s.i] = siblingsToZKInputFormat(p.Siblings)
 	}
 
 	exitAccount, err := getAccountInTreeDB(exitTree.DB(), tx.FromIdx)
@@ -442,16 +641,16 @@ func (s *StateDB) applyExit(exitTree *merkletree.MerkleTree, tx *common.Tx) (*co
 			EthAddr:   acc.EthAddr,
 		}
 		_, err = createAccountInTreeDB(exitTree.DB(), exitTree, tx.FromIdx, exitAccount)
-		return exitAccount, err
+		return exitAccount, true, err
 	} else if err != nil {
-		return exitAccount, err
+		return exitAccount, false, err
 	}
 
 	// 1b. if idx already exist in exitTree:
 	// update account, where account.Balance += exitAmount
 	exitAccount.Balance = new(big.Int).Add(exitAccount.Balance, tx.Amount)
 	_, err = updateAccountInTreeDB(exitTree.DB(), exitTree, tx.FromIdx, exitAccount)
-	return exitAccount, err
+	return exitAccount, false, err
 }
 
 // getIdx returns the stored Idx from the localStateDB, which is the last Idx
diff --git a/db/statedb/utils.go b/db/statedb/utils.go
index ce46240..7ba3d74 100644
--- a/db/statedb/utils.go
+++ b/db/statedb/utils.go
@@ -1,9 +1,12 @@
 package statedb
 
 import (
+	"math/big"
+
 	ethCommon "github.com/ethereum/go-ethereum/common"
 	"github.com/hermeznetwork/hermez-node/common"
 	"github.com/iden3/go-iden3-crypto/babyjub"
+	"github.com/iden3/go-merkletree"
 )
 
 // TODO
@@ -15,3 +18,28 @@ func (s *StateDB) getIdxByEthAddr(addr ethCommon.Address) common.Idx {
 func (s *StateDB) getIdxByBJJ(pk *babyjub.PublicKey) common.Idx {
 	return common.Idx(0)
 }
+
+func siblingsToZKInputFormat(s []*merkletree.Hash) []*big.Int {
+	b := make([]*big.Int, len(s))
+	for i := 0; i < len(s); i++ {
+		b[i] = s[i].BigInt()
+	}
+	return b
+}
+
+// BJJCompressedTo256BigInts returns a [256]*big.Int array with the bit
+// representation of the babyjub.PublicKeyComp
+func BJJCompressedTo256BigInts(pkComp babyjub.PublicKeyComp) [256]*big.Int {
+	var r [256]*big.Int
+	b := pkComp[:]
+
+	for i := 0; i < 256; i++ {
+		if b[i/8]&(1<<(i%8)) == 0 {
+			r[i] = big.NewInt(0)
+		} else {
+			r[i] = big.NewInt(1)
+		}
+	}
+
+	return r
+}
diff --git a/common/utils_test.go b/db/statedb/utils_test.go
similarity index 97%
rename from common/utils_test.go
rename to db/statedb/utils_test.go
index e058de5..c4453ca 100644
--- a/common/utils_test.go
+++ b/db/statedb/utils_test.go
@@ -1,4 +1,4 @@
-package common
+package statedb
 
 import (
 	"math/big"