1 Commits

Author SHA1 Message Date
druiz0992
423d5f0ce7 Add G1/G2 table calculation functionality 2020-05-06 09:27:15 +02:00
4 changed files with 478 additions and 480 deletions

View File

@@ -1,21 +1,19 @@
package prover
import (
"math/big"
bn256 "github.com/ethereum/go-ethereum/crypto/bn256/cloudflare"
cryptoConstants "github.com/iden3/go-iden3-crypto/constants"
"math/big"
)
type TableG1 struct{
type TableG1 struct {
data []*bn256.G1
}
func (t TableG1) GetData() []*bn256.G1 {
return t.data
}
// Compute table of gsize elements as ::
// Table[0] = Inf
// Table[1] = a[0]
@@ -23,7 +21,7 @@ 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)
@@ -31,18 +29,18 @@ func (t *TableG1) NewTableG1(a []*bn256.G1, gsize int){
a_ext := make([]*bn256.G1, 0)
a_ext = append(a_ext, a...)
for i:=len(a); i<gsize; i++ {
a_ext = append(a_ext,new(bn256.G1).ScalarBaseMult(big.NewInt(0)))
for i := len(a); i < gsize; i++ {
a_ext = append(a_ext, new(bn256.G1).ScalarBaseMult(big.NewInt(0)))
}
elG1 := new(bn256.G1).ScalarBaseMult(big.NewInt(0))
table = append(table,elG1)
table = append(table, elG1)
last_pow2 := 1
nelems := 0
for i :=1; i< 1<<gsize; i++ {
for i := 1; i < 1<<gsize; i++ {
elG1 := new(bn256.G1)
// if power of 2
if i & (i-1) == 0{
if i&(i-1) == 0 {
last_pow2 = i
elG1.Set(a_ext[nelems])
nelems++
@@ -53,34 +51,49 @@ func (t *TableG1) NewTableG1(a []*bn256.G1, gsize int){
}
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 {
// We need at least gsize elements. If not enough, fill with 0
k_ext := make([]*big.Int, 0)
k_ext = append(k_ext, k...)
for i:=len(k); i < gsize; i++ {
k_ext = append(k_ext,new(big.Int).SetUint64(0))
for i := len(k); i < gsize; i++ {
k_ext = append(k_ext, new(big.Int).SetUint64(0))
}
Q := new(bn256.G1).ScalarBaseMult(big.NewInt(0))
msb := getMsb(k_ext)
for i := msb-1; i >= 0; i-- {
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)
Q = new(bn256.G1).Add(Q, Q)
b := getBit(k_ext, 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 {
return Q.Add(Q,Q_prev)
return Q.Add(Q, Q_prev)
} else {
return Q
}
@@ -93,22 +106,22 @@ func MulTableNoDoubleG1(t []TableG1, k []*big.Int, Q_prev *bn256.G1, gsize int)
k_ext := make([]*big.Int, 0)
k_ext = append(k_ext, k...)
for i := len(k); i < min_nelems; i++ {
k_ext = append(k_ext,new(big.Int).SetUint64(0))
k_ext = append(k_ext, new(big.Int).SetUint64(0))
}
// Init Adders
nbitsQ := cryptoConstants.Q.BitLen()
Q := make([]*bn256.G1,nbitsQ)
Q := make([]*bn256.G1, nbitsQ)
for i:=0; i< nbitsQ; i++ {
for i := 0; i < nbitsQ; i++ {
Q[i] = new(bn256.G1).ScalarBaseMult(big.NewInt(0))
}
// Perform bitwise addition
for j:=0; j < len(t); j++ {
msb := getMsb(k_ext[j*gsize:(j+1)*gsize])
for j := 0; j < len(t); j++ {
msb := getMsb(k_ext[j*gsize : (j+1)*gsize])
for i := msb-1; i >= 0; i-- {
b := getBit(k_ext[j*gsize:(j+1)*gsize],i)
for i := msb - 1; i >= 0; i-- {
b := getBit(k_ext[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])
@@ -118,14 +131,14 @@ func MulTableNoDoubleG1(t []TableG1, k []*big.Int, Q_prev *bn256.G1, gsize int)
// Consolidate Addition
R := new(bn256.G1).Set(Q[nbitsQ-1])
for i:=nbitsQ-1; i>0; i-- {
for i := nbitsQ - 1; i > 0; i-- {
// TODO. bn256 doesn't export double operation. We will need to fork repo and export it
R = new(bn256.G1).Add(R,R)
R.Add(R,Q[i-1])
R = new(bn256.G1).Add(R, R)
R.Add(R, Q[i-1])
}
if Q_prev != nil {
return R.Add(R,Q_prev)
return R.Add(R, Q_prev)
} else {
return R
}
@@ -136,17 +149,17 @@ func MulTableNoDoubleG1(t []TableG1, k []*big.Int, Q_prev *bn256.G1, gsize int)
func ScalarMultG1(a []*bn256.G1, k []*big.Int, Q_prev *bn256.G1, gsize int) *bn256.G1 {
ntables := int((len(a) + gsize - 1) / gsize)
table := TableG1{}
Q:= new(bn256.G1).ScalarBaseMult(new(big.Int))
Q := new(bn256.G1).ScalarBaseMult(new(big.Int))
for i:=0; i<ntables-1; i++ {
table.NewTableG1( a[i*gsize:(i+1)*gsize], gsize)
for i := 0; i < ntables-1; i++ {
table.NewTableG1(a[i*gsize:(i+1)*gsize], gsize, false)
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)
if Q_prev != nil {
return Q.Add(Q,Q_prev)
return Q.Add(Q, Q_prev)
} else {
return Q
}
@@ -162,34 +175,34 @@ func ScalarMultNoDoubleG1(a []*bn256.G1, k []*big.Int, Q_prev *bn256.G1, gsize i
k_ext := make([]*big.Int, 0)
k_ext = append(k_ext, k...)
for i := len(k); i < min_nelems; i++ {
k_ext = append(k_ext,new(big.Int).SetUint64(0))
k_ext = append(k_ext, new(big.Int).SetUint64(0))
}
// Init Adders
nbitsQ := cryptoConstants.Q.BitLen()
Q := make([]*bn256.G1,nbitsQ)
Q := make([]*bn256.G1, nbitsQ)
for i:=0; i< nbitsQ; i++ {
for i := 0; i < nbitsQ; i++ {
Q[i] = new(bn256.G1).ScalarBaseMult(big.NewInt(0))
}
// Perform bitwise addition
for j:=0; j < ntables-1; j++ {
table.NewTableG1( a[j*gsize:(j+1)*gsize], gsize)
msb := getMsb(k_ext[j*gsize:(j+1)*gsize])
for j := 0; j < ntables-1; j++ {
table.NewTableG1(a[j*gsize:(j+1)*gsize], gsize, false)
msb := getMsb(k_ext[j*gsize : (j+1)*gsize])
for i := msb-1; i >= 0; i-- {
b := getBit(k_ext[j*gsize:(j+1)*gsize],i)
for i := msb - 1; i >= 0; i-- {
b := getBit(k_ext[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:])
for i := msb-1; i >= 0; i-- {
b := getBit(k_ext[(ntables-1)*gsize:],i)
for i := msb - 1; i >= 0; i-- {
b := getBit(k_ext[(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])
@@ -198,13 +211,13 @@ func ScalarMultNoDoubleG1(a []*bn256.G1, k []*big.Int, Q_prev *bn256.G1, gsize i
// Consolidate Addition
R := new(bn256.G1).Set(Q[nbitsQ-1])
for i:=nbitsQ-1; i>0; i-- {
for i := nbitsQ - 1; i > 0; i-- {
// TODO. bn256 doesn't export double operation. We will need to fork repo and export it
R = new(bn256.G1).Add(R,R)
R.Add(R,Q[i-1])
R = new(bn256.G1).Add(R, R)
R.Add(R, Q[i-1])
}
if Q_prev != nil {
return R.Add(R,Q_prev)
return R.Add(R, Q_prev)
} else {
return R
}
@@ -215,16 +228,14 @@ 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 {
return t.data
}
// Compute table of gsize elements as ::
// Table[0] = Inf
// Table[1] = a[0]
@@ -232,7 +243,8 @@ 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)
@@ -240,18 +252,18 @@ func (t *TableG2) NewTableG2(a []*bn256.G2, gsize int){
a_ext := make([]*bn256.G2, 0)
a_ext = append(a_ext, a...)
for i:=len(a); i<gsize; i++ {
a_ext = append(a_ext,new(bn256.G2).ScalarBaseMult(big.NewInt(0)))
for i := len(a); i < gsize; i++ {
a_ext = append(a_ext, new(bn256.G2).ScalarBaseMult(big.NewInt(0)))
}
elG2 := new(bn256.G2).ScalarBaseMult(big.NewInt(0))
table = append(table,elG2)
table = append(table, elG2)
last_pow2 := 1
nelems := 0
for i :=1; i< 1<<gsize; i++ {
for i := 1; i < 1<<gsize; i++ {
elG2 := new(bn256.G2)
// if power of 2
if i & (i-1) == 0{
if i&(i-1) == 0 {
last_pow2 = i
elG2.Set(a_ext[nelems])
nelems++
@@ -262,27 +274,42 @@ func (t *TableG2) NewTableG2(a []*bn256.G2, gsize int){
}
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 {
// We need at least gsize elements. If not enough, fill with 0
k_ext := make([]*big.Int, 0)
k_ext = append(k_ext, k...)
for i:=len(k); i < gsize; i++ {
k_ext = append(k_ext,new(big.Int).SetUint64(0))
for i := len(k); i < gsize; i++ {
k_ext = append(k_ext, new(big.Int).SetUint64(0))
}
Q := new(bn256.G2).ScalarBaseMult(big.NewInt(0))
msb := getMsb(k_ext)
for i := msb-1; i >= 0; i-- {
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)
Q = new(bn256.G2).Add(Q, Q)
b := getBit(k_ext, i)
if b != 0 {
// TODO. bn256 doesn't export mixed addition (Jacobian + Affine), which is more efficient.
Q.Add(Q, t.data[b])
@@ -302,22 +329,22 @@ func MulTableNoDoubleG2(t []TableG2, k []*big.Int, Q_prev *bn256.G2, gsize int)
k_ext := make([]*big.Int, 0)
k_ext = append(k_ext, k...)
for i := len(k); i < min_nelems; i++ {
k_ext = append(k_ext,new(big.Int).SetUint64(0))
k_ext = append(k_ext, new(big.Int).SetUint64(0))
}
// Init Adders
nbitsQ := cryptoConstants.Q.BitLen()
Q := make([]*bn256.G2,nbitsQ)
Q := make([]*bn256.G2, nbitsQ)
for i:=0; i< nbitsQ; i++ {
for i := 0; i < nbitsQ; i++ {
Q[i] = new(bn256.G2).ScalarBaseMult(big.NewInt(0))
}
// Perform bitwise addition
for j:=0; j < len(t); j++ {
msb := getMsb(k_ext[j*gsize:(j+1)*gsize])
for j := 0; j < len(t); j++ {
msb := getMsb(k_ext[j*gsize : (j+1)*gsize])
for i := msb-1; i >= 0; i-- {
b := getBit(k_ext[j*gsize:(j+1)*gsize],i)
for i := msb - 1; i >= 0; i-- {
b := getBit(k_ext[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])
@@ -327,13 +354,13 @@ func MulTableNoDoubleG2(t []TableG2, k []*big.Int, Q_prev *bn256.G2, gsize int)
// Consolidate Addition
R := new(bn256.G2).Set(Q[nbitsQ-1])
for i:=nbitsQ-1; i>0; i-- {
for i := nbitsQ - 1; i > 0; i-- {
// TODO. bn256 doesn't export double operation. We will need to fork repo and export it
R = new(bn256.G2).Add(R,R)
R.Add(R,Q[i-1])
R = new(bn256.G2).Add(R, R)
R.Add(R, Q[i-1])
}
if Q_prev != nil {
return R.Add(R,Q_prev)
return R.Add(R, Q_prev)
} else {
return R
}
@@ -344,17 +371,17 @@ func MulTableNoDoubleG2(t []TableG2, k []*big.Int, Q_prev *bn256.G2, gsize int)
func ScalarMultG2(a []*bn256.G2, k []*big.Int, Q_prev *bn256.G2, gsize int) *bn256.G2 {
ntables := int((len(a) + gsize - 1) / gsize)
table := TableG2{}
Q:= new(bn256.G2).ScalarBaseMult(new(big.Int))
Q := new(bn256.G2).ScalarBaseMult(new(big.Int))
for i:=0; i<ntables-1; i++ {
table.NewTableG2( a[i*gsize:(i+1)*gsize], gsize)
for i := 0; i < ntables-1; i++ {
table.NewTableG2(a[i*gsize:(i+1)*gsize], gsize, false)
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)
if Q_prev != nil {
return Q.Add(Q,Q_prev)
return Q.Add(Q, Q_prev)
} else {
return Q
}
@@ -370,34 +397,34 @@ func ScalarMultNoDoubleG2(a []*bn256.G2, k []*big.Int, Q_prev *bn256.G2, gsize i
k_ext := make([]*big.Int, 0)
k_ext = append(k_ext, k...)
for i := len(k); i < min_nelems; i++ {
k_ext = append(k_ext,new(big.Int).SetUint64(0))
k_ext = append(k_ext, new(big.Int).SetUint64(0))
}
// Init Adders
nbitsQ := cryptoConstants.Q.BitLen()
Q := make([]*bn256.G2,nbitsQ)
Q := make([]*bn256.G2, nbitsQ)
for i:=0; i< nbitsQ; i++ {
for i := 0; i < nbitsQ; i++ {
Q[i] = new(bn256.G2).ScalarBaseMult(big.NewInt(0))
}
// Perform bitwise addition
for j:=0; j < ntables-1; j++ {
table.NewTableG2( a[j*gsize:(j+1)*gsize], gsize)
msb := getMsb(k_ext[j*gsize:(j+1)*gsize])
for j := 0; j < ntables-1; j++ {
table.NewTableG2(a[j*gsize:(j+1)*gsize], gsize, false)
msb := getMsb(k_ext[j*gsize : (j+1)*gsize])
for i := msb-1; i >= 0; i-- {
b := getBit(k_ext[j*gsize:(j+1)*gsize],i)
for i := msb - 1; i >= 0; i-- {
b := getBit(k_ext[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:])
for i := msb-1; i >= 0; i-- {
b := getBit(k_ext[(ntables-1)*gsize:],i)
for i := msb - 1; i >= 0; i-- {
b := getBit(k_ext[(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])
@@ -406,23 +433,23 @@ func ScalarMultNoDoubleG2(a []*bn256.G2, k []*big.Int, Q_prev *bn256.G2, gsize i
// Consolidate Addition
R := new(bn256.G2).Set(Q[nbitsQ-1])
for i:=nbitsQ-1; i>0; i-- {
for i := nbitsQ - 1; i > 0; i-- {
// TODO. bn256 doesn't export double operation. We will need to fork repo and export it
R = new(bn256.G2).Add(R,R)
R.Add(R,Q[i-1])
R = new(bn256.G2).Add(R, R)
R.Add(R, Q[i-1])
}
if Q_prev != nil {
return R.Add(R,Q_prev)
return R.Add(R, Q_prev)
} else {
return R
}
}
// Return most significant bit position in a group of Big Integers
func getMsb(k []*big.Int) int{
func getMsb(k []*big.Int) int {
msb := 0
for _, el := range(k){
for _, el := range k {
tmp_msb := el.BitLen()
if tmp_msb > msb {
msb = tmp_msb
@@ -435,7 +462,7 @@ func getMsb(k []*big.Int) int{
func getBit(k []*big.Int, i int) uint {
table_idx := uint(0)
for idx, el := range(k){
for idx, el := range k {
b := el.Bit(i)
table_idx += (b << idx)
}

View File

@@ -1,13 +1,13 @@
package prover
import (
"bytes"
"crypto/rand"
"fmt"
bn256 "github.com/ethereum/go-ethereum/crypto/bn256/cloudflare"
"math/big"
"testing"
bn256 "github.com/ethereum/go-ethereum/crypto/bn256/cloudflare"
"time"
"bytes"
"fmt"
)
const (
@@ -15,7 +15,7 @@ const (
N2 = 5000
)
func randomBigIntArray(n int) []*big.Int{
func randomBigIntArray(n int) []*big.Int {
var p []*big.Int
for i := 0; i < n; i++ {
pi := randBI()
@@ -28,7 +28,7 @@ func randomBigIntArray(n int) []*big.Int{
func randomG1Array(n int) []*bn256.G1 {
arrayG1 := make([]*bn256.G1, n)
for i:=0; i<n; i++ {
for i := 0; i < n; i++ {
_, arrayG1[i], _ = bn256.RandomG1(rand.Reader)
}
return arrayG1
@@ -37,15 +37,13 @@ func randomG1Array(n int) []*bn256.G1 {
func randomG2Array(n int) []*bn256.G2 {
arrayG2 := make([]*bn256.G2, n)
for i:=0; i<n; i++ {
for i := 0; i < n; i++ {
_, arrayG2[i], _ = bn256.RandomG2(rand.Reader)
}
return arrayG2
}
func TestTableG1(t *testing.T){
func TestTableG1(t *testing.T) {
n := N1
// init scalar
@@ -55,57 +53,56 @@ func TestTableG1(t *testing.T){
beforeT := time.Now()
Q1 := new(bn256.G1).ScalarBaseMult(new(big.Int))
for i:=0; i < n; i++ {
for i := 0; i < n; i++ {
Q1.Add(Q1, new(bn256.G1).ScalarMult(arrayG1[i], arrayW[i]))
}
fmt.Println("Std. Mult. time elapsed:", time.Since(beforeT))
for gsize:=2; gsize < 10; gsize++ {
for gsize := 2; gsize < 10; gsize++ {
ntables := int((n + gsize - 1) / gsize)
table := make([]TableG1, ntables)
for i:=0; i<ntables-1; i++ {
table[i].NewTableG1( arrayG1[i*gsize:(i+1)*gsize], gsize)
for i := 0; i < ntables-1; i++ {
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 := 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[ntables-1].MulTableG1(arrayW[(ntables-1)*gsize:], Q2, gsize)
fmt.Printf("Gsize : %d, TMult time elapsed: %s\n", gsize,time.Since(beforeT))
fmt.Printf("Gsize : %d, TMult time elapsed: %s\n", gsize, time.Since(beforeT))
beforeT = time.Now()
Q3 := ScalarMultG1(arrayG1, arrayW, nil, gsize)
fmt.Printf("Gsize : %d, TMult time elapsed (inc table comp): %s\n", gsize,time.Since(beforeT))
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)
fmt.Printf("Gsize : %d, TMultNoDouble time elapsed: %s\n", gsize,time.Since(beforeT))
fmt.Printf("Gsize : %d, TMultNoDouble time elapsed: %s\n", gsize, time.Since(beforeT))
beforeT = time.Now()
Q5 := ScalarMultNoDoubleG1(arrayG1, arrayW, nil, gsize)
fmt.Printf("Gsize : %d, TMultNoDouble time elapsed (inc table comp): %s\n", gsize,time.Since(beforeT))
fmt.Printf("Gsize : %d, TMultNoDouble time elapsed (inc table comp): %s\n", gsize, time.Since(beforeT))
if bytes.Compare(Q1.Marshal(),Q2.Marshal()) != 0 {
if bytes.Compare(Q1.Marshal(), Q2.Marshal()) != 0 {
t.Error("Error in TMult")
}
if bytes.Compare(Q1.Marshal(),Q3.Marshal()) != 0 {
if bytes.Compare(Q1.Marshal(), Q3.Marshal()) != 0 {
t.Error("Error in TMult with table comp")
}
if bytes.Compare(Q1.Marshal(),Q4.Marshal()) != 0 {
if bytes.Compare(Q1.Marshal(), Q4.Marshal()) != 0 {
t.Error("Error in TMultNoDouble")
}
if bytes.Compare(Q1.Marshal(),Q5.Marshal()) != 0 {
if bytes.Compare(Q1.Marshal(), Q5.Marshal()) != 0 {
t.Error("Error in TMultNoDoublee with table comp")
}
}
}
func TestTableG2(t *testing.T){
func TestTableG2(t *testing.T) {
n := N2
// init scalar
@@ -115,51 +112,50 @@ func TestTableG2(t *testing.T){
beforeT := time.Now()
Q1 := new(bn256.G2).ScalarBaseMult(new(big.Int))
for i:=0; i < n; i++ {
for i := 0; i < n; i++ {
Q1.Add(Q1, new(bn256.G2).ScalarMult(arrayG2[i], arrayW[i]))
}
fmt.Println("Std. Mult. time elapsed:", time.Since(beforeT))
for gsize:=2; gsize < 10; gsize++ {
for gsize := 2; gsize < 10; gsize++ {
ntables := int((n + gsize - 1) / gsize)
table := make([]TableG2, ntables)
for i:=0; i<ntables-1; i++ {
table[i].NewTableG2( arrayG2[i*gsize:(i+1)*gsize], gsize)
for i := 0; i < ntables-1; i++ {
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 := 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[ntables-1].MulTableG2(arrayW[(ntables-1)*gsize:], Q2, gsize)
fmt.Printf("Gsize : %d, TMult time elapsed: %s\n", gsize,time.Since(beforeT))
fmt.Printf("Gsize : %d, TMult time elapsed: %s\n", gsize, time.Since(beforeT))
beforeT = time.Now()
Q3 := ScalarMultG2(arrayG2, arrayW, nil, gsize)
fmt.Printf("Gsize : %d, TMult time elapsed (inc table comp): %s\n", gsize,time.Since(beforeT))
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)
fmt.Printf("Gsize : %d, TMultNoDouble time elapsed: %s\n", gsize,time.Since(beforeT))
fmt.Printf("Gsize : %d, TMultNoDouble time elapsed: %s\n", gsize, time.Since(beforeT))
beforeT = time.Now()
Q5 := ScalarMultNoDoubleG2(arrayG2, arrayW, nil, gsize)
fmt.Printf("Gsize : %d, TMultNoDouble time elapsed (inc table comp): %s\n", gsize,time.Since(beforeT))
fmt.Printf("Gsize : %d, TMultNoDouble time elapsed (inc table comp): %s\n", gsize, time.Since(beforeT))
if bytes.Compare(Q1.Marshal(),Q2.Marshal()) != 0 {
if bytes.Compare(Q1.Marshal(), Q2.Marshal()) != 0 {
t.Error("Error in TMult")
}
if bytes.Compare(Q1.Marshal(),Q3.Marshal()) != 0 {
if bytes.Compare(Q1.Marshal(), Q3.Marshal()) != 0 {
t.Error("Error in TMult with table comp")
}
if bytes.Compare(Q1.Marshal(),Q4.Marshal()) != 0 {
if bytes.Compare(Q1.Marshal(), Q4.Marshal()) != 0 {
t.Error("Error in TMultNoDouble")
}
if bytes.Compare(Q1.Marshal(),Q5.Marshal()) != 0 {
if bytes.Compare(Q1.Marshal(), Q5.Marshal()) != 0 {
t.Error("Error in TMultNoDoublee with table comp")
}
}

View File

@@ -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 |

View File

@@ -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 |