Add proof parsers to string (decimal & hex)

Also adds ProofToSmartContractFormat, which returns a ProofString as the
proof.B elements swap is not a valid point for the bn256.G2 format.

Also unexports internal structs and methods of the prover package.
Also apply golint.

parsers/parsers.go

@@ -467,8 +467,35 @@ func stringToG2(h [][]string) (*bn256.G2, error) {
 	return p, err
 }
 
-// ProofToJson outputs the Proof i Json format
+// ProofStringToSmartContractFormat converts the ProofString to a ProofString in the SmartContract format in a ProofString structure
-func ProofToJson(p *types.Proof) ([]byte, error) {
+func ProofStringToSmartContractFormat(s ProofString) ProofString {
+	var rs ProofString
+	rs.A = make([]string, 2)
+	rs.B = make([][]string, 2)
+	rs.B[0] = make([]string, 2)
+	rs.B[1] = make([]string, 2)
+	rs.C = make([]string, 2)
+
+	rs.A[0] = s.A[0]
+	rs.A[1] = s.A[1]
+	rs.B[0][0] = s.B[0][1]
+	rs.B[0][1] = s.B[0][0]
+	rs.B[1][0] = s.B[1][1]
+	rs.B[1][1] = s.B[1][0]
+	rs.C[0] = s.C[0]
+	rs.C[1] = s.C[1]
+	rs.Protocol = s.Protocol
+	return rs
+}
+
+// ProofToSmartContractFormat converts the *types.Proof to a ProofString in the SmartContract format in a ProofString structure
+func ProofToSmartContractFormat(p *types.Proof) ProofString {
+	s := ProofToString(p)
+	return ProofStringToSmartContractFormat(s)
+}
+
+// ProofToString converts the Proof to ProofString
+func ProofToString(p *types.Proof) ProofString {
 	var ps ProofString
 	ps.A = make([]string, 3)
 	ps.B = make([][]string, 3)
@@ -497,10 +524,55 @@ func ProofToJson(p *types.Proof) ([]byte, error) {
 
 	ps.Protocol = "groth"
 
+	return ps
+}
+
+// ProofToJson outputs the Proof i Json format
+func ProofToJson(p *types.Proof) ([]byte, error) {
+	ps := ProofToString(p)
 	return json.Marshal(ps)
 }
 
-// ParseWitness parses binary file representation of the Witness into the Witness struct
+// ProofToHex converts the Proof to ProofString with hexadecimal strings
+func ProofToHex(p *types.Proof) ProofString {
+	var ps ProofString
+	ps.A = make([]string, 3)
+	ps.B = make([][]string, 3)
+	ps.B[0] = make([]string, 2)
+	ps.B[1] = make([]string, 2)
+	ps.B[2] = make([]string, 2)
+	ps.C = make([]string, 3)
+
+	a := p.A.Marshal()
+	ps.A[0] = "0x" + hex.EncodeToString(new(big.Int).SetBytes(a[:32]).Bytes())
+	ps.A[1] = "0x" + hex.EncodeToString(new(big.Int).SetBytes(a[32:64]).Bytes())
+	ps.A[2] = "1"
+
+	b := p.B.Marshal()
+	ps.B[0][1] = "0x" + hex.EncodeToString(new(big.Int).SetBytes(b[:32]).Bytes())
+	ps.B[0][0] = "0x" + hex.EncodeToString(new(big.Int).SetBytes(b[32:64]).Bytes())
+	ps.B[1][1] = "0x" + hex.EncodeToString(new(big.Int).SetBytes(b[64:96]).Bytes())
+	ps.B[1][0] = "0x" + hex.EncodeToString(new(big.Int).SetBytes(b[96:128]).Bytes())
+	ps.B[2][0] = "1"
+	ps.B[2][1] = "0"
+
+	c := p.C.Marshal()
+	ps.C[0] = "0x" + hex.EncodeToString(new(big.Int).SetBytes(c[:32]).Bytes())
+	ps.C[1] = "0x" + hex.EncodeToString(new(big.Int).SetBytes(c[32:64]).Bytes())
+	ps.C[2] = "1"
+
+	ps.Protocol = "groth"
+
+	return ps
+}
+
+// ProofToJsonHex outputs the Proof i Json format with hexadecimal strings
+func ProofToJsonHex(p *types.Proof) ([]byte, error) {
+	ps := ProofToHex(p)
+	return json.Marshal(ps)
+}
+
+// ParseWitnessBin parses binary file representation of the Witness into the Witness struct
 func ParseWitnessBin(f *os.File) (types.Witness, error) {
 	var w types.Witness
 	r := bufio.NewReader(f)

parsers/parsers_test.go

@@ -172,3 +172,27 @@ func TestParseWitnessBin(t *testing.T) {
 	testCircuitParseWitnessBin(t, "circuit1k")
 	testCircuitParseWitnessBin(t, "circuit5k")
 }
+
+func TestProofSmartContractFormat(t *testing.T) {
+	proofJson, err := ioutil.ReadFile("../testdata/circuit1k/proof.json")
+	require.Nil(t, err)
+	proof, err := ParseProof(proofJson)
+	require.Nil(t, err)
+	pS := ProofToString(proof)
+
+	pSC := ProofToSmartContractFormat(proof)
+	assert.Nil(t, err)
+	assert.Equal(t, pS.A[0], pSC.A[0])
+	assert.Equal(t, pS.A[1], pSC.A[1])
+	assert.Equal(t, pS.B[0][0], pSC.B[0][1])
+	assert.Equal(t, pS.B[0][1], pSC.B[0][0])
+	assert.Equal(t, pS.B[1][0], pSC.B[1][1])
+	assert.Equal(t, pS.B[1][1], pSC.B[1][0])
+	assert.Equal(t, pS.C[0], pSC.C[0])
+	assert.Equal(t, pS.C[1], pSC.C[1])
+	assert.Equal(t, pS.Protocol, pSC.Protocol)
+
+	pSC2 := ProofStringToSmartContractFormat(pS)
+	assert.Equal(t, pSC, pSC2)
+
+}

prover/gextra.go

@@ -2,20 +2,19 @@ package prover
 
 import (
 	"math/big"
+
 	bn256 "github.com/ethereum/go-ethereum/crypto/bn256/cloudflare"
 	cryptoConstants "github.com/iden3/go-iden3-crypto/constants"
 )
 
-type TableG1 struct{
+type tableG1 struct {
 	data []*bn256.G1
 }
 
-
+func (t tableG1) getData() []*bn256.G1 {
-func (t TableG1) GetData() []*bn256.G1 {
 	return t.data
 }
 
-
 // Compute table of gsize elements as ::
 //  Table[0] = Inf
 //  Table[1] = a[0]
@@ -23,77 +22,91 @@ func (t TableG1) GetData() []*bn256.G1 {
 //  Table[3] = a[0]+a[1]
 //  .....
 //  Table[(1<<gsize)-1] = a[0]+a[1]+...+a[gsize-1]
-func (t *TableG1) NewTableG1(a []*bn256.G1, gsize int){
+func (t *tableG1) newTableG1(a []*bn256.G1, gsize int, toaffine bool) {
 	// EC table
 	table := make([]*bn256.G1, 0)
 
 	// We need at least gsize elements. If not enough, fill with 0
-   a_ext := make([]*bn256.G1, 0)
+	aExt := make([]*bn256.G1, 0)
-   a_ext = append(a_ext, a...)
+	aExt = append(aExt, a...)
 
 	for i := len(a); i < gsize; i++ {
-      a_ext = append(a_ext,new(bn256.G1).ScalarBaseMult(big.NewInt(0)))
+		aExt = append(aExt, new(bn256.G1).ScalarBaseMult(big.NewInt(0)))
 	}
 
 	elG1 := new(bn256.G1).ScalarBaseMult(big.NewInt(0))
 	table = append(table, elG1)
-   last_pow2 := 1
+	lastPow2 := 1
 	nelems := 0
 	for i := 1; i < 1<<gsize; i++ {
 		elG1 := new(bn256.G1)
 		// if power of 2
 		if i&(i-1) == 0 {
-        last_pow2 = i
+			lastPow2 = i
-        elG1.Set(a_ext[nelems])
+			elG1.Set(aExt[nelems])
 			nelems++
 		} else {
-        elG1.Add(table[last_pow2], table[i-last_pow2])
+			elG1.Add(table[lastPow2], table[i-lastPow2])
 			// TODO bn256 doesn't export MakeAffine function. We need to fork repo
 			//table[i].MakeAffine()
 		}
 		table = append(table, elG1)
 	}
+	if toaffine {
+		for i := 0; i < len(table); i++ {
+			info := table[i].Marshal()
+			table[i].Unmarshal(info)
+		}
+	}
 	t.data = table
 }
 
+func (t tableG1) Marshal() []byte {
+	info := make([]byte, 0)
+	for _, el := range t.data {
+		info = append(info, el.Marshal()...)
+	}
+
+	return info
+}
+
 // Multiply scalar by precomputed table of G1 elements
-func (t *TableG1) MulTableG1(k []*big.Int, Q_prev *bn256.G1, gsize int) *bn256.G1 {
+func (t *tableG1) mulTableG1(k []*big.Int, qPrev *bn256.G1, gsize int) *bn256.G1 {
 	// We need at least gsize elements. If not enough, fill with 0
-   k_ext := make([]*big.Int, 0)
+	kExt := make([]*big.Int, 0)
-   k_ext = append(k_ext, k...)
+	kExt = append(kExt, k...)
 
 	for i := len(k); i < gsize; i++ {
-      k_ext = append(k_ext,new(big.Int).SetUint64(0))
+		kExt = append(kExt, new(big.Int).SetUint64(0))
 	}
 
 	Q := new(bn256.G1).ScalarBaseMult(big.NewInt(0))
 
-   msb := getMsb(k_ext)
+	msb := getMsb(kExt)
 
 	for i := msb - 1; i >= 0; i-- {
 		// TODO. bn256 doesn't export double operation. We will need to fork repo and export it
 		Q = new(bn256.G1).Add(Q, Q)
-        b := getBit(k_ext,i)
+		b := getBit(kExt, i)
 		if b != 0 {
 			// TODO. bn256 doesn't export mixed addition (Jacobian + Affine), which is more efficient.
 			Q.Add(Q, t.data[b])
 		}
 	}
-   if Q_prev != nil {
+	if qPrev != nil {
-     return Q.Add(Q,Q_prev)
+		return Q.Add(Q, qPrev)
-   } else {
-     return Q
 	}
+	return Q
 }
 
 // Multiply scalar by precomputed table of G1 elements without intermediate doubling
-func MulTableNoDoubleG1(t []TableG1, k []*big.Int,  Q_prev *bn256.G1, gsize int) *bn256.G1 {
+func mulTableNoDoubleG1(t []tableG1, k []*big.Int, qPrev *bn256.G1, gsize int) *bn256.G1 {
 	// We need at least gsize elements. If not enough, fill with 0
-   min_nelems := len(t) * gsize
+	minNElems := len(t) * gsize
-   k_ext := make([]*big.Int, 0)
+	kExt := make([]*big.Int, 0)
-   k_ext = append(k_ext, k...)
+	kExt = append(kExt, k...)
-   for i := len(k); i <  min_nelems; i++ {
+	for i := len(k); i < minNElems; i++ {
-      k_ext = append(k_ext,new(big.Int).SetUint64(0))
+		kExt = append(kExt, new(big.Int).SetUint64(0))
 	}
 	// Init Adders
 	nbitsQ := cryptoConstants.Q.BitLen()
@@ -105,10 +118,10 @@ func MulTableNoDoubleG1(t []TableG1, k []*big.Int,  Q_prev *bn256.G1, gsize int)
 
 	// Perform bitwise addition
 	for j := 0; j < len(t); j++ {
-     msb := getMsb(k_ext[j*gsize:(j+1)*gsize])
+		msb := getMsb(kExt[j*gsize : (j+1)*gsize])
 
 		for i := msb - 1; i >= 0; i-- {
-        b := getBit(k_ext[j*gsize:(j+1)*gsize],i)
+			b := getBit(kExt[j*gsize:(j+1)*gsize], i)
 			if b != 0 {
 				// TODO. bn256 doesn't export mixed addition (Jacobian + Affine), which is more efficient.
 				Q[i].Add(Q[i], t[j].data[b])
@@ -124,45 +137,43 @@ func MulTableNoDoubleG1(t []TableG1, k []*big.Int,  Q_prev *bn256.G1, gsize int)
 		R.Add(R, Q[i-1])
 	}
 
-   if Q_prev != nil {
+	if qPrev != nil {
-      return R.Add(R,Q_prev)
+		return R.Add(R, qPrev)
-   } else {
-      return R
 	}
+	return R
 }
 
 // Compute tables within function. This solution should still be faster than std  multiplication
 // for gsize = 7
-func ScalarMultG1(a []*bn256.G1, k []*big.Int, Q_prev *bn256.G1, gsize int) *bn256.G1 {
+func scalarMultG1(a []*bn256.G1, k []*big.Int, qPrev *bn256.G1, gsize int) *bn256.G1 {
 	ntables := int((len(a) + gsize - 1) / gsize)
-     table := TableG1{}
+	table := tableG1{}
 	Q := new(bn256.G1).ScalarBaseMult(new(big.Int))
 
 	for i := 0; i < ntables-1; i++ {
-       table.NewTableG1( a[i*gsize:(i+1)*gsize], gsize)
+		table.newTableG1(a[i*gsize:(i+1)*gsize], gsize, false)
-       Q = table.MulTableG1(k[i*gsize:(i+1)*gsize], Q, gsize)
+		Q = table.mulTableG1(k[i*gsize:(i+1)*gsize], Q, gsize)
 	}
-     table.NewTableG1( a[(ntables-1)*gsize:], gsize)
+	table.newTableG1(a[(ntables-1)*gsize:], gsize, false)
-     Q = table.MulTableG1(k[(ntables-1)*gsize:], Q, gsize)
+	Q = table.mulTableG1(k[(ntables-1)*gsize:], Q, gsize)
 
-     if Q_prev != nil {
+	if qPrev != nil {
-        return Q.Add(Q,Q_prev)
+		return Q.Add(Q, qPrev)
-     } else {
-        return Q
 	}
+	return Q
 }
 
 // Multiply scalar by precomputed table of G1 elements without intermediate doubling
-func ScalarMultNoDoubleG1(a []*bn256.G1, k []*big.Int, Q_prev *bn256.G1, gsize int) *bn256.G1 {
+func scalarMultNoDoubleG1(a []*bn256.G1, k []*big.Int, qPrev *bn256.G1, gsize int) *bn256.G1 {
 	ntables := int((len(a) + gsize - 1) / gsize)
-   table := TableG1{}
+	table := tableG1{}
 
 	// We need at least gsize elements. If not enough, fill with 0
-   min_nelems := ntables * gsize
+	minNElems := ntables * gsize
-   k_ext := make([]*big.Int, 0)
+	kExt := make([]*big.Int, 0)
-   k_ext = append(k_ext, k...)
+	kExt = append(kExt, k...)
-   for i := len(k); i <  min_nelems; i++ {
+	for i := len(k); i < minNElems; i++ {
-      k_ext = append(k_ext,new(big.Int).SetUint64(0))
+		kExt = append(kExt, new(big.Int).SetUint64(0))
 	}
 	// Init Adders
 	nbitsQ := cryptoConstants.Q.BitLen()
@@ -174,22 +185,22 @@ func ScalarMultNoDoubleG1(a []*bn256.G1, k []*big.Int, Q_prev *bn256.G1, gsize i
 
 	// Perform bitwise addition
 	for j := 0; j < ntables-1; j++ {
-     table.NewTableG1( a[j*gsize:(j+1)*gsize], gsize)
+		table.newTableG1(a[j*gsize:(j+1)*gsize], gsize, false)
-     msb := getMsb(k_ext[j*gsize:(j+1)*gsize])
+		msb := getMsb(kExt[j*gsize : (j+1)*gsize])
 
 		for i := msb - 1; i >= 0; i-- {
-        b := getBit(k_ext[j*gsize:(j+1)*gsize],i)
+			b := getBit(kExt[j*gsize:(j+1)*gsize], i)
 			if b != 0 {
 				// TODO. bn256 doesn't export mixed addition (Jacobian + Affine), which is more efficient.
 				Q[i].Add(Q[i], table.data[b])
 			}
 		}
 	}
-   table.NewTableG1( a[(ntables-1)*gsize:], gsize)
+	table.newTableG1(a[(ntables-1)*gsize:], gsize, false)
-   msb := getMsb(k_ext[(ntables-1)*gsize:])
+	msb := getMsb(kExt[(ntables-1)*gsize:])
 
 	for i := msb - 1; i >= 0; i-- {
-     b := getBit(k_ext[(ntables-1)*gsize:],i)
+		b := getBit(kExt[(ntables-1)*gsize:], i)
 		if b != 0 {
 			// TODO. bn256 doesn't export mixed addition (Jacobian + Affine), which is more efficient.
 			Q[i].Add(Q[i], table.data[b])
@@ -203,11 +214,10 @@ func ScalarMultNoDoubleG1(a []*bn256.G1, k []*big.Int, Q_prev *bn256.G1, gsize i
 		R = new(bn256.G1).Add(R, R)
 		R.Add(R, Q[i-1])
 	}
-   if Q_prev != nil {
+	if qPrev != nil {
-     return R.Add(R,Q_prev)
+		return R.Add(R, qPrev)
-   } else {
-     return R
 	}
+	return R
 }
 
 /////
@@ -215,16 +225,14 @@ func ScalarMultNoDoubleG1(a []*bn256.G1, k []*big.Int, Q_prev *bn256.G1, gsize i
 // TODO - How can avoid replicating code in G2?
 //G2
 
-type TableG2 struct{
+type tableG2 struct {
 	data []*bn256.G2
 }
 
-
+func (t tableG2) getData() []*bn256.G2 {
-func (t TableG2) GetData() []*bn256.G2 {
 	return t.data
 }
 
-
 // Compute table of gsize elements as ::
 //  Table[0] = Inf
 //  Table[1] = a[0]
@@ -232,77 +240,92 @@ func (t TableG2) GetData() []*bn256.G2 {
 //  Table[3] = a[0]+a[1]
 //  .....
 //  Table[(1<<gsize)-1] = a[0]+a[1]+...+a[gsize-1]
-func (t *TableG2) NewTableG2(a []*bn256.G2, gsize int){
+// TODO -> toaffine = True doesnt work. Problem with Marshal/Unmarshal
+func (t *tableG2) newTableG2(a []*bn256.G2, gsize int, toaffine bool) {
 	// EC table
 	table := make([]*bn256.G2, 0)
 
 	// We need at least gsize elements. If not enough, fill with 0
-   a_ext := make([]*bn256.G2, 0)
+	aExt := make([]*bn256.G2, 0)
-   a_ext = append(a_ext, a...)
+	aExt = append(aExt, a...)
 
 	for i := len(a); i < gsize; i++ {
-      a_ext = append(a_ext,new(bn256.G2).ScalarBaseMult(big.NewInt(0)))
+		aExt = append(aExt, new(bn256.G2).ScalarBaseMult(big.NewInt(0)))
 	}
 
 	elG2 := new(bn256.G2).ScalarBaseMult(big.NewInt(0))
 	table = append(table, elG2)
-   last_pow2 := 1
+	lastPow2 := 1
 	nelems := 0
 	for i := 1; i < 1<<gsize; i++ {
 		elG2 := new(bn256.G2)
 		// if power of 2
 		if i&(i-1) == 0 {
-        last_pow2 = i
+			lastPow2 = i
-        elG2.Set(a_ext[nelems])
+			elG2.Set(aExt[nelems])
 			nelems++
 		} else {
-        elG2.Add(table[last_pow2], table[i-last_pow2])
+			elG2.Add(table[lastPow2], table[i-lastPow2])
 			// TODO bn256 doesn't export MakeAffine function. We need to fork repo
 			//table[i].MakeAffine()
 		}
 		table = append(table, elG2)
 	}
+	if toaffine {
+		for i := 0; i < len(table); i++ {
+			info := table[i].Marshal()
+			table[i].Unmarshal(info)
+		}
+	}
 	t.data = table
 }
 
+func (t tableG2) Marshal() []byte {
+	info := make([]byte, 0)
+	for _, el := range t.data {
+		info = append(info, el.Marshal()...)
+	}
+
+	return info
+}
+
 // Multiply scalar by precomputed table of G2 elements
-func (t *TableG2) MulTableG2(k []*big.Int, Q_prev *bn256.G2, gsize int) *bn256.G2 {
+func (t *tableG2) mulTableG2(k []*big.Int, qPrev *bn256.G2, gsize int) *bn256.G2 {
 	// We need at least gsize elements. If not enough, fill with 0
-   k_ext := make([]*big.Int, 0)
+	kExt := make([]*big.Int, 0)
-   k_ext = append(k_ext, k...)
+	kExt = append(kExt, k...)
 
 	for i := len(k); i < gsize; i++ {
-      k_ext = append(k_ext,new(big.Int).SetUint64(0))
+		kExt = append(kExt, new(big.Int).SetUint64(0))
 	}
 
 	Q := new(bn256.G2).ScalarBaseMult(big.NewInt(0))
 
-   msb := getMsb(k_ext)
+	msb := getMsb(kExt)
 
 	for i := msb - 1; i >= 0; i-- {
 		// TODO. bn256 doesn't export double operation. We will need to fork repo and export it
 		Q = new(bn256.G2).Add(Q, Q)
-        b := getBit(k_ext,i)
+		b := getBit(kExt, i)
 		if b != 0 {
 			// TODO. bn256 doesn't export mixed addition (Jacobian + Affine), which is more efficient.
 			Q.Add(Q, t.data[b])
 		}
 	}
-   if Q_prev != nil {
+	if qPrev != nil {
-     return Q.Add(Q, Q_prev)
+		return Q.Add(Q, qPrev)
-   } else {
-     return Q
 	}
+	return Q
 }
 
 // Multiply scalar by precomputed table of G2 elements without intermediate doubling
-func MulTableNoDoubleG2(t []TableG2, k []*big.Int, Q_prev *bn256.G2, gsize int) *bn256.G2 {
+func mulTableNoDoubleG2(t []tableG2, k []*big.Int, qPrev *bn256.G2, gsize int) *bn256.G2 {
 	// We need at least gsize elements. If not enough, fill with 0
-   min_nelems := len(t) * gsize
+	minNElems := len(t) * gsize
-   k_ext := make([]*big.Int, 0)
+	kExt := make([]*big.Int, 0)
-   k_ext = append(k_ext, k...)
+	kExt = append(kExt, k...)
-   for i := len(k); i <  min_nelems; i++ {
+	for i := len(k); i < minNElems; i++ {
-      k_ext = append(k_ext,new(big.Int).SetUint64(0))
+		kExt = append(kExt, new(big.Int).SetUint64(0))
 	}
 	// Init Adders
 	nbitsQ := cryptoConstants.Q.BitLen()
@@ -314,10 +337,10 @@ func MulTableNoDoubleG2(t []TableG2, k []*big.Int, Q_prev *bn256.G2, gsize int)
 
 	// Perform bitwise addition
 	for j := 0; j < len(t); j++ {
-     msb := getMsb(k_ext[j*gsize:(j+1)*gsize])
+		msb := getMsb(kExt[j*gsize : (j+1)*gsize])
 
 		for i := msb - 1; i >= 0; i-- {
-        b := getBit(k_ext[j*gsize:(j+1)*gsize],i)
+			b := getBit(kExt[j*gsize:(j+1)*gsize], i)
 			if b != 0 {
 				// TODO. bn256 doesn't export mixed addition (Jacobian + Affine), which is more efficient.
 				Q[i].Add(Q[i], t[j].data[b])
@@ -332,45 +355,43 @@ func MulTableNoDoubleG2(t []TableG2, k []*big.Int, Q_prev *bn256.G2, gsize int)
 		R = new(bn256.G2).Add(R, R)
 		R.Add(R, Q[i-1])
 	}
-   if Q_prev != nil {
+	if qPrev != nil {
-     return R.Add(R,Q_prev)
+		return R.Add(R, qPrev)
-   } else {
-     return R
 	}
+	return R
 }
 
 // Compute tables within function. This solution should still be faster than std  multiplication
 // for gsize = 7
-func ScalarMultG2(a []*bn256.G2, k []*big.Int, Q_prev *bn256.G2, gsize int) *bn256.G2 {
+func scalarMultG2(a []*bn256.G2, k []*big.Int, qPrev *bn256.G2, gsize int) *bn256.G2 {
 	ntables := int((len(a) + gsize - 1) / gsize)
-     table := TableG2{}
+	table := tableG2{}
 	Q := new(bn256.G2).ScalarBaseMult(new(big.Int))
 
 	for i := 0; i < ntables-1; i++ {
-       table.NewTableG2( a[i*gsize:(i+1)*gsize], gsize)
+		table.newTableG2(a[i*gsize:(i+1)*gsize], gsize, false)
-       Q = table.MulTableG2(k[i*gsize:(i+1)*gsize], Q, gsize)
+		Q = table.mulTableG2(k[i*gsize:(i+1)*gsize], Q, gsize)
 	}
-     table.NewTableG2( a[(ntables-1)*gsize:], gsize)
+	table.newTableG2(a[(ntables-1)*gsize:], gsize, false)
-     Q = table.MulTableG2(k[(ntables-1)*gsize:], Q, gsize)
+	Q = table.mulTableG2(k[(ntables-1)*gsize:], Q, gsize)
 
-     if Q_prev != nil {
+	if qPrev != nil {
-       return Q.Add(Q,Q_prev)
+		return Q.Add(Q, qPrev)
-     } else {
-       return Q
 	}
+	return Q
 }
 
 // Multiply scalar by precomputed table of G2 elements without intermediate doubling
-func ScalarMultNoDoubleG2(a []*bn256.G2, k []*big.Int, Q_prev *bn256.G2, gsize int) *bn256.G2 {
+func scalarMultNoDoubleG2(a []*bn256.G2, k []*big.Int, qPrev *bn256.G2, gsize int) *bn256.G2 {
 	ntables := int((len(a) + gsize - 1) / gsize)
-   table := TableG2{}
+	table := tableG2{}
 
 	// We need at least gsize elements. If not enough, fill with 0
-   min_nelems := ntables * gsize
+	minNElems := ntables * gsize
-   k_ext := make([]*big.Int, 0)
+	kExt := make([]*big.Int, 0)
-   k_ext = append(k_ext, k...)
+	kExt = append(kExt, k...)
-   for i := len(k); i <  min_nelems; i++ {
+	for i := len(k); i < minNElems; i++ {
-      k_ext = append(k_ext,new(big.Int).SetUint64(0))
+		kExt = append(kExt, new(big.Int).SetUint64(0))
 	}
 	// Init Adders
 	nbitsQ := cryptoConstants.Q.BitLen()
@@ -382,22 +403,22 @@ func ScalarMultNoDoubleG2(a []*bn256.G2, k []*big.Int, Q_prev *bn256.G2, gsize i
 
 	// Perform bitwise addition
 	for j := 0; j < ntables-1; j++ {
-     table.NewTableG2( a[j*gsize:(j+1)*gsize], gsize)
+		table.newTableG2(a[j*gsize:(j+1)*gsize], gsize, false)
-     msb := getMsb(k_ext[j*gsize:(j+1)*gsize])
+		msb := getMsb(kExt[j*gsize : (j+1)*gsize])
 
 		for i := msb - 1; i >= 0; i-- {
-        b := getBit(k_ext[j*gsize:(j+1)*gsize],i)
+			b := getBit(kExt[j*gsize:(j+1)*gsize], i)
 			if b != 0 {
 				// TODO. bn256 doesn't export mixed addition (Jacobian + Affine), which is more efficient.
 				Q[i].Add(Q[i], table.data[b])
 			}
 		}
 	}
-   table.NewTableG2( a[(ntables-1)*gsize:], gsize)
+	table.newTableG2(a[(ntables-1)*gsize:], gsize, false)
-   msb := getMsb(k_ext[(ntables-1)*gsize:])
+	msb := getMsb(kExt[(ntables-1)*gsize:])
 
 	for i := msb - 1; i >= 0; i-- {
-     b := getBit(k_ext[(ntables-1)*gsize:],i)
+		b := getBit(kExt[(ntables-1)*gsize:], i)
 		if b != 0 {
 			// TODO. bn256 doesn't export mixed addition (Jacobian + Affine), which is more efficient.
 			Q[i].Add(Q[i], table.data[b])
@@ -411,21 +432,20 @@ func ScalarMultNoDoubleG2(a []*bn256.G2, k []*big.Int, Q_prev *bn256.G2, gsize i
 		R = new(bn256.G2).Add(R, R)
 		R.Add(R, Q[i-1])
 	}
-   if Q_prev != nil {
+	if qPrev != nil {
-     return R.Add(R,Q_prev)
+		return R.Add(R, qPrev)
-   } else {
-     return R
 	}
+	return R
 }
 
 // Return most significant bit position in a group of Big Integers
 func getMsb(k []*big.Int) int {
 	msb := 0
 
-  for _, el := range(k){
+	for _, el := range k {
-     tmp_msb := el.BitLen()
+		tmpMsb := el.BitLen()
-     if tmp_msb > msb {
+		if tmpMsb > msb {
-        msb = tmp_msb
+			msb = tmpMsb
 		}
 	}
 	return msb
@@ -433,11 +453,11 @@ func getMsb(k []*big.Int) int{
 
 // Return ith bit in group of Big Integers
 func getBit(k []*big.Int, i int) uint {
-   table_idx := uint(0)
+	tableIdx := uint(0)
 
-   for idx, el := range(k){
+	for idx, el := range k {
 		b := el.Bit(i)
-     table_idx += (b << idx)
+		tableIdx += (b << idx)
 	}
-   return table_idx
+	return tableIdx
 }

prover/gextra_test.go

@@ -1,13 +1,14 @@
 package prover
 
 import (
+	"bytes"
 	"crypto/rand"
+	"fmt"
 	"math/big"
 	"testing"
-	bn256 "github.com/ethereum/go-ethereum/crypto/bn256/cloudflare"
 	"time"
-        "bytes"
+
-        "fmt"
+	bn256 "github.com/ethereum/go-ethereum/crypto/bn256/cloudflare"
 )
 
 const (
@@ -43,8 +44,6 @@ func randomG2Array(n int) []*bn256.G2 {
 	return arrayG2
 }
 
-
-
 func TestTableG1(t *testing.T) {
 	n := N1
 
@@ -62,34 +61,33 @@ func TestTableG1(t *testing.T){
 
 	for gsize := 2; gsize < 10; gsize++ {
 		ntables := int((n + gsize - 1) / gsize)
-        table := make([]TableG1, ntables)
+		table := make([]tableG1, ntables)
 
 		for i := 0; i < ntables-1; i++ {
-          table[i].NewTableG1( arrayG1[i*gsize:(i+1)*gsize], gsize)
+			table[i].newTableG1(arrayG1[i*gsize:(i+1)*gsize], gsize, true)
 		}
-        table[ntables-1].NewTableG1( arrayG1[(ntables-1)*gsize:], gsize)
+		table[ntables-1].newTableG1(arrayG1[(ntables-1)*gsize:], gsize, true)
 
 		beforeT = time.Now()
 		Q2 := new(bn256.G1).ScalarBaseMult(new(big.Int))
 		for i := 0; i < ntables-1; i++ {
-           Q2 = table[i].MulTableG1(arrayW[i*gsize:(i+1)*gsize], Q2, gsize)
+			Q2 = table[i].mulTableG1(arrayW[i*gsize:(i+1)*gsize], Q2, gsize)
 		}
-        Q2 = table[ntables-1].MulTableG1(arrayW[(ntables-1)*gsize:], Q2, gsize)
+		Q2 = table[ntables-1].mulTableG1(arrayW[(ntables-1)*gsize:], Q2, gsize)
 		fmt.Printf("Gsize : %d, TMult time elapsed: %s\n", gsize, time.Since(beforeT))
 
 		beforeT = time.Now()
-        Q3 := ScalarMultG1(arrayG1, arrayW, nil, gsize)
+		Q3 := scalarMultG1(arrayG1, arrayW, nil, gsize)
 		fmt.Printf("Gsize : %d, TMult time elapsed (inc table comp): %s\n", gsize, time.Since(beforeT))
 
 		beforeT = time.Now()
-        Q4 := MulTableNoDoubleG1(table, arrayW, nil, gsize)
+		Q4 := mulTableNoDoubleG1(table, arrayW, nil, gsize)
 		fmt.Printf("Gsize : %d, TMultNoDouble time elapsed: %s\n", gsize, time.Since(beforeT))
 
 		beforeT = time.Now()
-        Q5 := ScalarMultNoDoubleG1(arrayG1, arrayW, nil, gsize)
+		Q5 := scalarMultNoDoubleG1(arrayG1, arrayW, nil, gsize)
 		fmt.Printf("Gsize : %d, TMultNoDouble time elapsed (inc table comp): %s\n", gsize, time.Since(beforeT))
 
-
 		if bytes.Compare(Q1.Marshal(), Q2.Marshal()) != 0 {
 			t.Error("Error in TMult")
 		}
@@ -122,34 +120,33 @@ func TestTableG2(t *testing.T){
 
 	for gsize := 2; gsize < 10; gsize++ {
 		ntables := int((n + gsize - 1) / gsize)
-        table := make([]TableG2, ntables)
+		table := make([]tableG2, ntables)
 
 		for i := 0; i < ntables-1; i++ {
-          table[i].NewTableG2( arrayG2[i*gsize:(i+1)*gsize], gsize)
+			table[i].newTableG2(arrayG2[i*gsize:(i+1)*gsize], gsize, false)
 		}
-        table[ntables-1].NewTableG2( arrayG2[(ntables-1)*gsize:], gsize)
+		table[ntables-1].newTableG2(arrayG2[(ntables-1)*gsize:], gsize, false)
 
 		beforeT = time.Now()
 		Q2 := new(bn256.G2).ScalarBaseMult(new(big.Int))
 		for i := 0; i < ntables-1; i++ {
-           Q2 =table[i].MulTableG2(arrayW[i*gsize:(i+1)*gsize], Q2, gsize)
+			Q2 = table[i].mulTableG2(arrayW[i*gsize:(i+1)*gsize], Q2, gsize)
 		}
-        Q2 = table[ntables-1].MulTableG2(arrayW[(ntables-1)*gsize:], Q2, gsize)
+		Q2 = table[ntables-1].mulTableG2(arrayW[(ntables-1)*gsize:], Q2, gsize)
 		fmt.Printf("Gsize : %d, TMult time elapsed: %s\n", gsize, time.Since(beforeT))
 
 		beforeT = time.Now()
-        Q3 := ScalarMultG2(arrayG2, arrayW, nil, gsize)
+		Q3 := scalarMultG2(arrayG2, arrayW, nil, gsize)
 		fmt.Printf("Gsize : %d, TMult time elapsed (inc table comp): %s\n", gsize, time.Since(beforeT))
 
 		beforeT = time.Now()
-        Q4 := MulTableNoDoubleG2(table, arrayW, nil, gsize)
+		Q4 := mulTableNoDoubleG2(table, arrayW, nil, gsize)
 		fmt.Printf("Gsize : %d, TMultNoDouble time elapsed: %s\n", gsize, time.Since(beforeT))
 
 		beforeT = time.Now()
-        Q5 := ScalarMultNoDoubleG2(arrayG2, arrayW, nil, gsize)
+		Q5 := scalarMultNoDoubleG2(arrayG2, arrayW, nil, gsize)
 		fmt.Printf("Gsize : %d, TMultNoDouble time elapsed (inc table comp): %s\n", gsize, time.Since(beforeT))
 
-
 		if bytes.Compare(Q1.Marshal(), Q2.Marshal()) != 0 {
 			t.Error("Error in TMult")
 		}

prover/prover.go

@@ -87,25 +87,25 @@ func GenerateProof(pk *types.Pk, w types.Witness) (*types.Proof, []*big.Int, err
 	for _cpu, _ranges := range ranges(pk.NVars, numcpu) {
 		// split 1
 		go func(cpu int, ranges [2]int) {
-                        proofA[cpu] = ScalarMultNoDoubleG1(pk.A[ranges[0]:ranges[1]],
+			proofA[cpu] = scalarMultNoDoubleG1(pk.A[ranges[0]:ranges[1]],
 				w[ranges[0]:ranges[1]],
 				proofA[cpu],
 				gsize)
-                        proofB[cpu] = ScalarMultNoDoubleG2(pk.B2[ranges[0]:ranges[1]],
+			proofB[cpu] = scalarMultNoDoubleG2(pk.B2[ranges[0]:ranges[1]],
 				w[ranges[0]:ranges[1]],
 				proofB[cpu],
 				gsize)
-                        proofBG1[cpu] = ScalarMultNoDoubleG1(pk.B1[ranges[0]:ranges[1]],
+			proofBG1[cpu] = scalarMultNoDoubleG1(pk.B1[ranges[0]:ranges[1]],
 				w[ranges[0]:ranges[1]],
 				proofBG1[cpu],
 				gsize)
-                        min_lim := pk.NPublic+1
+			minLim := pk.NPublic + 1
 			if ranges[0] > pk.NPublic+1 {
-                           min_lim = ranges[0]
+				minLim = ranges[0]
 			}
 			if ranges[1] > pk.NPublic+1 {
-                            proofC[cpu] = ScalarMultNoDoubleG1(pk.C[min_lim:ranges[1]],
+				proofC[cpu] = scalarMultNoDoubleG1(pk.C[minLim:ranges[1]],
-                                                           w[min_lim:ranges[1]],
+					w[minLim:ranges[1]],
 					proofC[cpu],
 					gsize)
 			}
@@ -142,7 +142,7 @@ func GenerateProof(pk *types.Pk, w types.Witness) (*types.Proof, []*big.Int, err
 	for _cpu, _ranges := range ranges(len(h), numcpu) {
 		// split 2
 		go func(cpu int, ranges [2]int) {
-                        proofC[cpu] = ScalarMultNoDoubleG1(pk.HExps[ranges[0]:ranges[1]],
+			proofC[cpu] = scalarMultNoDoubleG1(pk.HExps[ranges[0]:ranges[1]],
 				h[ranges[0]:ranges[1]],
 				proofC[cpu],
 				gsize)

prover/tables.md

@@ -16,7 +16,7 @@ There may be some concern on the additional size of the tables since they need t
 
 
 | Algorithm (G1) | GS 2 | GS 3 | GS 4 | GS 5 | GS 6 | GS 7 | GS 8 | GS 9 | 
-|---|---|---|---|---|---|---|---|---|
+|---|---|---|--|---|---|---|---|---|
 | Naive | 6.63s | - | - | - | - | - |  - | - |
 | Strauss |  13.16s | 9.03s | 6.95s | 5.61s | 4.91s | 4.26s | 3.88s | 3.54 s |
 | Strauss + Table Computation | 16.13s | 11.32s | 8.47s | 7.10s | 6.2s | 5.94s | 6.01s | 6.69s |
@@ -26,7 +26,7 @@ There may be some concern on the additional size of the tables since they need t
 There are 5000 G2 Elliptical Curve Points, and the scalars are 254 bits (BN256 curve). 
 
 | Algorithm (G2) | GS 2 | GS 3 | GS 4 | GS 5 | GS 6 | GS 7 | GS 8 | GS 9 | 
-|---|---|---|---|---|---|---|---|---|
+|---|---|---|--|---|---|---|---|---|
 | Naive | 3.55s | | | | | | | |
 | Strauss |  3.55s | 2.54s | 1.96s | 1.58s |  1.38s | 1.20s | 1.03s | 937ms |
 | Strauss + Table Computation | 3.59s | 2.58s | 2.04s | 1.71s | 1.51s | 1.46s | 1.51s | 1.82s |

tables.md

@@ -1,25 +0,0 @@
-# Tables Pre-calculation
-The most time consuming part of a ZKSnark proof calculation is the scalar multiplication of elliptic curve points. Direct mechanism accumulates each multiplication. However, prover only needs the total accumulation.
-
-There are two potential improvements to the naive approach:
-
-1. Apply Strauss-Shamir method (https://stackoverflow.com/questions/50993471/ec-scalar-multiplication-with-strauss-shamir-method).
-2. Leave the doubling operation for the last step
-
-Both options can be combined. 
-
-In the following table, we show the results of using the naive method, Srauss-Shamir and Strauss-Shamir + No doubling. These last two options are repeated for different table grouping order.
-
-There are 5000 G1 Elliptical Curve Points, and the scalars are 254 bits (BN256 curve). 
-
-There may be some concern on the additional size of the tables since they need to be loaded into a smartphone during the proof, and the time required to load these tables may exceed the benefits. If this is a problem, another althernative is to compute the tables during the proof itself. Depending on the Group Size, timing may be better than the naive approach.
-
-
-| Algorithm | GS / Time |
-|---|---|---|
-| Naive | 6.63s | | | | | | | |
-| Strauss |  13.16s | 9.033s | 6.95s | 5.61s | 4.91s | 4.26s | 3.88s | 3.54 s | 1.44 s |
-| Strauss + Table Computation | 16.13s | 11.32s | 8.47s | 7.10s | 6.2s | 5.94s | 6.01s | 6.69s |
-| No Doubling | 3.74s | 3.00s | 2.38s | 1.96s | 1.79s | 1.54s | 1.50s | 1.44s|
-| No Doubling + Table Computation  | 6.83s | 5.1s | 4.16s | 3.52s| 3.22s | 3.21s | 3.57s | 4.56s |
-