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// Package common contains all the common data structures used at the
// hermez-node, zk.go contains the zkSnark inputs used to generate the proof
package common
import ( "crypto/sha256" "encoding/binary" "encoding/json" "fmt" "math/big"
"github.com/hermeznetwork/hermez-node/log" cryptoConstants "github.com/iden3/go-iden3-crypto/constants" "github.com/iden3/go-merkletree" "github.com/mitchellh/mapstructure")
// ZKMetadata contains ZKInputs metadata that is not used directly in the
// ZKInputs result, but to calculate values for Hash check
type ZKMetadata struct { // Circuit parameters
// absolute maximum of L1 or L2 transactions allowed
NTx uint32 // merkle tree depth
NLevels uint32 MaxLevels uint32 // absolute maximum of L1 transaction allowed
MaxL1Tx uint32 // total txs allowed
MaxTx uint32 // Maximum number of Idxs where Fees can be send in a batch (currently
// is constant for all circuits: 64)
MaxFeeIdxs uint32
L1TxsData [][]byte L2TxsData [][]byte ChainID uint16
NewLastIdxRaw Idx NewStateRootRaw *merkletree.Hash NewExitRootRaw *merkletree.Hash}
// ZKInputs represents the inputs that will be used to generate the zkSNARK proof
type ZKInputs struct { Metadata ZKMetadata
//
// General
//
// inputs for final `hashGlobalInputs`
// OldLastIdx is the last index assigned to an account
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 *big.Int `json:"globalChainID"` // uint16
// 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]
//
// Txs (L1&L2)
//
// transaction L1-L2
// TxCompressedData
TxCompressedData []*big.Int `json:"txCompressedData"` // big.Int (max 251 bits), len: [nTx]
// TxCompressedDataV2, only used in L2Txs, in L1Txs is set to 0
TxCompressedDataV2 []*big.Int `json:"txCompressedDataV2"` // big.Int (max 193 bits), len: [nTx]
// FromIdx
FromIdx []*big.Int `json:"fromIdx"` // uint64 (max nLevels bits), len: [nTx]
// AuxFromIdx is the Idx of the new created account which is consequence of a L1CreateAccountTx
AuxFromIdx []*big.Int `json:"auxFromIdx"` // uint64 (max nLevels bits), len: [nTx]
// 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 []*big.Int `json:"auxToIdx"` // uint64 (max nLevels bits), len: [nTx]
// ToBJJAy
ToBJJAy []*big.Int `json:"toBjjAy"` // big.Int, len: [nTx]
// ToEthAddr
ToEthAddr []*big.Int `json:"toEthAddr"` // ethCommon.Address, len: [nTx]
// OnChain determines if is L1 (1/true) or L2 (0/false)
OnChain []*big.Int `json:"onChain"` // bool, len: [nTx]
//
// Txs/L1Txs
//
// NewAccount boolean (0/1) flag set 'true' when L1 tx creates a new account (fromIdx==0)
NewAccount []*big.Int `json:"newAccount"` // bool, len: [nTx]
// LoadAmountF encoded as float16
LoadAmountF []*big.Int `json:"loadAmountF"` // uint16, len: [nTx]
// FromEthAddr
FromEthAddr []*big.Int `json:"fromEthAddr"` // ethCommon.Address, len: [nTx]
// FromBJJCompressed boolean encoded where each value is a *big.Int
FromBJJCompressed [][256]*big.Int `json:"fromBjjCompressed"` // bool array, len: [nTx][256]
//
// Txs/L2Txs
//
// RqOffset relative transaction position to be linked. Used to perform atomic transactions.
RqOffset []*big.Int `json:"rqOffset"` // uint8 (max 3 bits), len: [nTx]
// transaction L2 request data
// RqTxCompressedDataV2
RqTxCompressedDataV2 []*big.Int `json:"rqTxCompressedDataV2"` // big.Int (max 251 bits), len: [nTx]
// RqToEthAddr
RqToEthAddr []*big.Int `json:"rqToEthAddr"` // ethCommon.Address, len: [nTx]
// RqToBJJAy
RqToBJJAy []*big.Int `json:"rqToBjjAy"` // big.Int, len: [nTx]
// transaction L2 signature
// S
S []*big.Int `json:"s"` // big.Int, len: [nTx]
// R8x
R8x []*big.Int `json:"r8x"` // big.Int, len: [nTx]
// R8y
R8y []*big.Int `json:"r8y"` // big.Int, len: [nTx]
//
// State MerkleTree Leafs transitions
//
// state 1, value of the sender (from) account 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]
Ay1 []*big.Int `json:"ay1"` // big.Int, len: [nTx]
Balance1 []*big.Int `json:"balance1"` // big.Int (max 192 bits), len: [nTx]
EthAddr1 []*big.Int `json:"ethAddr1"` // ethCommon.Address, len: [nTx]
Siblings1 [][]*big.Int `json:"siblings1"` // big.Int, len: [nTx][nLevels + 1]
// Required for inserts and deletes, values of the CircomProcessorProof (smt insert proof)
IsOld0_1 []*big.Int `json:"isOld0_1"` // bool, len: [nTx]
OldKey1 []*big.Int `json:"oldKey1"` // uint64 (max 40 bits), len: [nTx]
OldValue1 []*big.Int `json:"oldValue1"` // Hash, len: [nTx]
// state 2, value of the receiver (to) account leaf
// if Tx is an Exit, state 2 is used for the Exit Merkle Proof
TokenID2 []*big.Int `json:"tokenID2"` // uint32, len: [nTx]
Nonce2 []*big.Int `json:"nonce2"` // uint64 (max 40 bits), len: [nTx]
Sign2 []*big.Int `json:"sign2"` // bool, len: [nTx]
Ay2 []*big.Int `json:"ay2"` // big.Int, len: [nTx]
Balance2 []*big.Int `json:"balance2"` // big.Int (max 192 bits), len: [nTx]
EthAddr2 []*big.Int `json:"ethAddr2"` // ethCommon.Address, len: [nTx]
Siblings2 [][]*big.Int `json:"siblings2"` // 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 `json:"newExit"` // bool, len: [nTx]
// Required for inserts and deletes, values of the CircomProcessorProof (smt insert proof)
IsOld0_2 []*big.Int `json:"isOld0_2"` // bool, len: [nTx]
OldKey2 []*big.Int `json:"oldKey2"` // uint64 (max 40 bits), len: [nTx]
OldValue2 []*big.Int `json:"oldValue2"` // Hash, len: [nTx]
// state 3, value of the account leaf receiver of the Fees
// fee tx
// State fees
TokenID3 []*big.Int `json:"tokenID3"` // uint32, len: [maxFeeIdxs]
Nonce3 []*big.Int `json:"nonce3"` // uint64 (max 40 bits), len: [maxFeeIdxs]
Sign3 []*big.Int `json:"sign3"` // bool, len: [maxFeeIdxs]
Ay3 []*big.Int `json:"ay3"` // big.Int, len: [maxFeeIdxs]
Balance3 []*big.Int `json:"balance3"` // big.Int (max 192 bits), len: [maxFeeIdxs]
EthAddr3 []*big.Int `json:"ethAddr3"` // ethCommon.Address, len: [maxFeeIdxs]
Siblings3 [][]*big.Int `json:"siblings3"` // Hash, len: [maxFeeIdxs][nLevels + 1]
//
// Intermediate States
//
// Intermediate States to parallelize witness computation
// Note: the Intermediate States (IS) of the last transaction does not
// exist. Meaning that transaction 3 (4th) will fill the parameters
// FromIdx[3] and ISOnChain[3], but last transaction (nTx-1) will fill
// FromIdx[nTx-1] but will not fill ISOnChain. That's why IS have
// length of nTx-1, while the other parameters have length of nTx.
// Last transaction does not need intermediate state since its output
// will not be used.
// decode-tx
// ISOnChain indicates if tx is L1 (true) or L2 (false)
ISOnChain []*big.Int `json:"imOnChain"` // bool, len: [nTx - 1]
// ISOutIdx current index account for each Tx
ISOutIdx []*big.Int `json:"imOutIdx"` // 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 `json:"imStateRoot"` // 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 `json:"imExitRoot"` // Hash, len: [nTx - 1]
// ISAccFeeOut accumulated fees once the Tx is processed
ISAccFeeOut [][]*big.Int `json:"imAccFeeOut"` // big.Int, len: [nTx - 1][maxFeeIdxs]
// 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 `json:"imStateRootFee"` // Hash, len: [maxFeeIdxs - 1]
// ISInitStateRootFee state root once all L1-L2 tx are processed (before computing the fees-tx)
ISInitStateRootFee *big.Int `json:"imInitStateRootFee"` // Hash
// ISFinalAccFee final accumulated fees (before computing the fees-tx)
ISFinalAccFee []*big.Int `json:"imFinalAccFee"` // big.Int, len: [maxFeeIdxs - 1]
}
func bigIntsToStrings(v interface{}) interface{} { switch c := v.(type) { case *big.Int: return c.String() case []*big.Int: r := make([]interface{}, len(c)) for i := range c { r[i] = bigIntsToStrings(c[i]) } return r case [256]*big.Int: r := make([]interface{}, len(c)) for i := range c { r[i] = bigIntsToStrings(c[i]) } return r case [][]*big.Int: r := make([]interface{}, len(c)) for i := range c { r[i] = bigIntsToStrings(c[i]) } return r case [][256]*big.Int: r := make([]interface{}, len(c)) for i := range c { r[i] = bigIntsToStrings(c[i]) } return r case map[string]interface{}: // avoid printing a warning when there is a struct type
default: log.Warnf("bigIntsToStrings unexpected type: %T\n", v) } return nil}
// MarshalJSON implements the json marshaler for ZKInputs
func (z ZKInputs) MarshalJSON() ([]byte, error) { var m map[string]interface{} dec, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{ TagName: "json", Result: &m, }) if err != nil { return nil, err } err = dec.Decode(z) if err != nil { return nil, err }
for k, v := range m { m[k] = bigIntsToStrings(v) } return json.Marshal(m)}
// NewZKInputs returns a pointer to an initialized struct of ZKInputs
func NewZKInputs(nTx, maxL1Tx, maxTx, maxFeeIdxs, nLevels uint32) *ZKInputs { zki := &ZKInputs{} zki.Metadata.NTx = nTx zki.Metadata.MaxFeeIdxs = maxFeeIdxs zki.Metadata.NLevels = nLevels zki.Metadata.MaxLevels = uint32(48) //nolint:gomnd
zki.Metadata.MaxL1Tx = maxL1Tx zki.Metadata.MaxTx = maxTx
// General
zki.OldLastIdx = big.NewInt(0) zki.OldStateRoot = big.NewInt(0) zki.GlobalChainID = big.NewInt(0) zki.FeeIdxs = newSlice(maxFeeIdxs) zki.FeePlanTokens = newSlice(maxFeeIdxs)
// 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.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++ { 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.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++ { 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(maxFeeIdxs) zki.Nonce3 = newSlice(maxFeeIdxs) zki.Sign3 = newSlice(maxFeeIdxs) zki.Ay3 = newSlice(maxFeeIdxs) zki.Balance3 = newSlice(maxFeeIdxs) zki.EthAddr3 = newSlice(maxFeeIdxs) zki.Siblings3 = make([][]*big.Int, maxFeeIdxs) 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(maxFeeIdxs) } zki.ISStateRootFee = newSlice(maxFeeIdxs - 1) zki.ISInitStateRootFee = big.NewInt(0) zki.ISFinalAccFee = newSlice(maxFeeIdxs - 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 uint32) []*big.Int { s := make([]*big.Int, n) for i := 0; i < len(s); i++ { s[i] = big.NewInt(0) } return s}
// HashGlobalData returns the HashGlobalData
func (z ZKInputs) HashGlobalData() (*big.Int, error) { b, err := z.ToHashGlobalData() if err != nil { return nil, err }
h := sha256.New() _, err = h.Write(b) if err != nil { return nil, err }
r := new(big.Int).SetBytes(h.Sum(nil)) v := r.Mod(r, cryptoConstants.Q)
return v, nil}
// ToHashGlobalData returns the data to be hashed in the method HashGlobalData
func (z ZKInputs) ToHashGlobalData() ([]byte, error) { var b []byte bytesMaxLevels := int(z.Metadata.MaxLevels / 8) //nolint:gomnd
// [MAX_NLEVELS bits] oldLastIdx
oldLastIdx := make([]byte, bytesMaxLevels) copy(oldLastIdx, z.OldLastIdx.Bytes()) b = append(b, SwapEndianness(oldLastIdx)...)
// [MAX_NLEVELS bits] newLastIdx
newLastIdx := make([]byte, bytesMaxLevels) newLastIdxBytes, err := z.Metadata.NewLastIdxRaw.Bytes() if err != nil { return nil, err } copy(newLastIdx, newLastIdxBytes[len(newLastIdxBytes)-bytesMaxLevels:]) b = append(b, newLastIdx...)
// [256 bits] oldStRoot
oldStateRoot := make([]byte, 32) copy(oldStateRoot, z.OldStateRoot.Bytes()) b = append(b, oldStateRoot...)
// [256 bits] newStateRoot
newStateRoot := make([]byte, 32) copy(newStateRoot, z.Metadata.NewStateRootRaw.Bytes()) b = append(b, newStateRoot...)
// [256 bits] newExitRoot
newExitRoot := make([]byte, 32) copy(newExitRoot, z.Metadata.NewExitRootRaw.Bytes()) b = append(b, newExitRoot...)
// [MAX_L1_TX * (2 * MAX_NLEVELS + 480) bits] L1TxsData
l1TxDataLen := (2*z.Metadata.MaxLevels + 480) l1TxsDataLen := (z.Metadata.MaxL1Tx * l1TxDataLen) l1TxsData := make([]byte, l1TxsDataLen/8) //nolint:gomnd
for i := 0; i < len(z.Metadata.L1TxsData); i++ { dataLen := int(l1TxDataLen) / 8 //nolint:gomnd
pos0 := i * dataLen pos1 := i*dataLen + dataLen copy(l1TxsData[pos0:pos1], z.Metadata.L1TxsData[i]) } b = append(b, l1TxsData...)
// [MAX_TX*(2*NLevels + 24) bits] L2TxsData
var l2TxsData []byte l2TxDataLen := 2*z.Metadata.NLevels + 24 //nolint:gomnd
l2TxsDataLen := (z.Metadata.MaxTx * l2TxDataLen) expectedL2TxsDataLen := l2TxsDataLen / 8 //nolint:gomnd
for i := 0; i < len(z.Metadata.L2TxsData); i++ { l2TxsData = append(l2TxsData, z.Metadata.L2TxsData[i]...) } if len(l2TxsData) > int(expectedL2TxsDataLen) { return nil, fmt.Errorf("len(l2TxsData): %d, expected: %d", len(l2TxsData), expectedL2TxsDataLen) }
l2TxsPadding := make([]byte, (int(z.Metadata.MaxTx)-len(z.Metadata.L2TxsData))*int(l2TxDataLen)/8) //nolint:gomnd
b = append(b, l2TxsPadding...) b = append(b, l2TxsData...)
// [NLevels * MAX_TOKENS_FEE bits] feeTxsData
for i := 0; i < len(z.FeeIdxs); i++ { var r []byte
padding := make([]byte, bytesMaxLevels/4) //nolint:gomnd
r = append(r, padding...)
feeIdx := make([]byte, bytesMaxLevels/2) //nolint:gomnd
feeIdxBytes := z.FeeIdxs[i].Bytes() copy(feeIdx[len(feeIdx)-len(feeIdxBytes):], feeIdxBytes[:]) r = append(r, feeIdx...) b = append(b, r...) }
// [16 bits] chainID
var chainID [2]byte binary.BigEndian.PutUint16(chainID[:], z.Metadata.ChainID) b = append(b, chainID[:]...)
return b, nil}
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