Add polynomials arithmetic in goff

Polynomials and ifft moved to goff (iden3/go-iden3-crypto/ff) instead of *big.Int.

Benchmarks:

- Before:
BenchmarkArithmetic/polynomialSub-4         	    2774	    441063 ns/op
BenchmarkArithmetic/polynomialMul-4         	       1	1135732757 ns/op
BenchmarkArithmetic/polynomialDiv-4         	     768	   1425192 ns/op
BenchmarkGenerateProof-4                    	       1	2844488975 ns/op

- With this commit:
BenchmarkArithmetic/polynomialSubE-4        	   23097	     54152 ns/op
BenchmarkArithmetic/polynomialMulE-4        	      25	  44914327 ns/op
BenchmarkArithmetic/polynomialDivE-4        	    8703	    132573 ns/op
BenchmarkGenerateProof-4                    	       1	1530398526 ns/op
This commit is contained in:
arnaucube
2020-04-20 12:37:49 +02:00
parent 3f5f8e2318
commit 324c817d42
7 changed files with 178 additions and 33 deletions

View File

@@ -3,6 +3,8 @@ package prover
import (
"bytes"
"math/big"
"github.com/iden3/go-iden3-crypto/ff"
)
func arrayOfZeroes(n int) []*big.Int {
@@ -12,6 +14,13 @@ func arrayOfZeroes(n int) []*big.Int {
}
return r
}
func arrayOfZeroesE(n int) []*ff.Element {
var r []*ff.Element
for i := 0; i < n; i++ {
r = append(r, ff.NewElement())
}
return r
}
func fAdd(a, b *big.Int) *big.Int {
ab := new(big.Int).Add(a, b)
@@ -75,6 +84,17 @@ func polynomialSub(a, b []*big.Int) []*big.Int {
return r
}
func polynomialSubE(a, b []*ff.Element) []*ff.Element {
r := arrayOfZeroesE(max(len(a), len(b)))
for i := 0; i < len(a); i++ {
r[i].Add(r[i], a[i])
}
for i := 0; i < len(b); i++ {
r[i].Sub(r[i], b[i])
}
return r
}
func polynomialMul(a, b []*big.Int) []*big.Int {
r := arrayOfZeroes(len(a) + len(b) - 1)
for i := 0; i < len(a); i++ {
@@ -85,6 +105,16 @@ func polynomialMul(a, b []*big.Int) []*big.Int {
return r
}
func polynomialMulE(a, b []*ff.Element) []*ff.Element {
r := arrayOfZeroesE(len(a) + len(b) - 1)
for i := 0; i < len(a); i++ {
for j := 0; j < len(b); j++ {
r[i+j].Add(r[i+j], ff.NewElement().Mul(a[i], b[j]))
}
}
return r
}
func polynomialDiv(a, b []*big.Int) ([]*big.Int, []*big.Int) {
// https://en.wikipedia.org/wiki/Division_algorithm
r := arrayOfZeroes(len(a) - len(b) + 1)
@@ -100,3 +130,31 @@ func polynomialDiv(a, b []*big.Int) ([]*big.Int, []*big.Int) {
}
return r, rem
}
func polynomialDivE(a, b []*ff.Element) ([]*ff.Element, []*ff.Element) {
// https://en.wikipedia.org/wiki/Division_algorithm
r := arrayOfZeroesE(len(a) - len(b) + 1)
rem := a
for len(rem) >= len(b) {
l := ff.NewElement().Div(rem[len(rem)-1], b[len(b)-1])
pos := len(rem) - len(b)
r[pos] = l
aux := arrayOfZeroesE(pos)
aux1 := append(aux, l)
aux2 := polynomialSubE(rem, polynomialMulE(b, aux1))
rem = aux2[:len(aux2)-1]
}
return r, rem
}
// once https://github.com/iden3/go-iden3-crypto/pull/22 is merged, use the fucntion from there
func ElementArrayToBigIntArray(e []*ff.Element) []*big.Int {
var o []*big.Int
for i := range e {
ei := e[i]
bi := big.NewInt(0)
ei.ToBigIntRegular(bi)
o = append(o, bi)
}
return o
}

66
prover/arithmetic_test.go Normal file
View File

@@ -0,0 +1,66 @@
package prover
import (
"crypto/rand"
"math/big"
"testing"
cryptoConstants "github.com/iden3/go-iden3-crypto/constants"
"github.com/iden3/go-iden3-crypto/utils"
)
func randBI() *big.Int {
maxbits := 253
b := make([]byte, (maxbits/8)-1)
_, err := rand.Read(b)
if err != nil {
panic(err)
}
r := new(big.Int).SetBytes(b)
return new(big.Int).Mod(r, cryptoConstants.Q)
}
func BenchmarkArithmetic(b *testing.B) {
// generate arrays with bigint
var p, q []*big.Int
for i := 0; i < 1000; i++ {
pi := randBI()
p = append(p, pi)
}
for i := 1000 - 1; i >= 0; i-- {
q = append(q, p[i])
}
pe := utils.BigIntArrayToElementArray(p)
qe := utils.BigIntArrayToElementArray(q)
b.Run("polynomialSub", func(b *testing.B) {
for i := 0; i < b.N; i++ {
polynomialSub(p, q)
}
})
b.Run("polynomialSubE", func(b *testing.B) {
for i := 0; i < b.N; i++ {
polynomialSubE(pe, qe)
}
})
b.Run("polynomialMul", func(b *testing.B) {
for i := 0; i < b.N; i++ {
polynomialMul(p, q)
}
})
b.Run("polynomialMulE", func(b *testing.B) {
for i := 0; i < b.N; i++ {
polynomialMulE(pe, qe)
}
})
b.Run("polynomialDiv", func(b *testing.B) {
for i := 0; i < b.N; i++ {
polynomialDiv(p, q)
}
})
b.Run("polynomialDivE", func(b *testing.B) {
for i := 0; i < b.N; i++ {
polynomialDivE(pe, qe)
}
})
}

View File

@@ -3,11 +3,13 @@ package prover
import (
"math"
"math/big"
"github.com/iden3/go-iden3-crypto/ff"
)
type rootsT struct {
roots [][]*big.Int
w []*big.Int
roots [][]*ff.Element
w []*ff.Element
}
func newRootsT() rootsT {
@@ -19,15 +21,15 @@ func newRootsT() rootsT {
s++
rem = new(big.Int).Rsh(rem, 1)
}
roots.w = make([]*big.Int, s+1)
roots.w[s] = fExp(big.NewInt(5), rem)
roots.w = make([]*ff.Element, s+1)
roots.w[s] = ff.NewElement().SetBigInt(fExp(big.NewInt(5), rem))
n := s - 1
for n >= 0 {
roots.w[n] = fMul(roots.w[n+1], roots.w[n+1])
roots.w[n] = ff.NewElement().Mul(roots.w[n+1], roots.w[n+1])
n--
}
roots.roots = make([][]*big.Int, 50) // TODO WIP
roots.roots = make([][]*ff.Element, 50) // TODO WIP
roots.setRoots(15)
return roots
@@ -35,25 +37,25 @@ func newRootsT() rootsT {
func (roots rootsT) setRoots(n int) {
for i := n; i >= 0 && nil == roots.roots[i]; i-- { // TODO tmp i<=len(r)
r := big.NewInt(1)
r := ff.NewElement().SetBigInt(big.NewInt(1))
nroots := 1 << i
var rootsi []*big.Int
var rootsi []*ff.Element
for j := 0; j < nroots; j++ {
rootsi = append(rootsi, r)
r = fMul(r, roots.w[i])
r = ff.NewElement().Mul(r, roots.w[i])
}
roots.roots[i] = rootsi
}
}
func fft(roots rootsT, pall []*big.Int, bits, offset, step int) []*big.Int {
func fft(roots rootsT, pall []*ff.Element, bits, offset, step int) []*ff.Element {
n := 1 << bits
if n == 1 {
return []*big.Int{pall[offset]}
return []*ff.Element{pall[offset]}
} else if n == 2 {
return []*big.Int{
fAdd(pall[offset], pall[offset+step]), // TODO tmp
fSub(pall[offset], pall[offset+step]),
return []*ff.Element{
ff.NewElement().Add(pall[offset], pall[offset+step]), // TODO tmp
ff.NewElement().Sub(pall[offset], pall[offset+step]),
}
}
@@ -61,17 +63,16 @@ func fft(roots rootsT, pall []*big.Int, bits, offset, step int) []*big.Int {
p1 := fft(roots, pall, bits-1, offset, step*2)
p2 := fft(roots, pall, bits-1, offset+step, step*2)
// var out []*big.Int
out := make([]*big.Int, n)
out := make([]*ff.Element, n)
for i := 0; i < ndiv2; i++ {
// fmt.Println(i, len(roots.roots))
out[i] = fAdd(p1[i], fMul(roots.roots[bits][i], p2[i]))
out[i+ndiv2] = fSub(p1[i], fMul(roots.roots[bits][i], p2[i]))
out[i] = ff.NewElement().Add(p1[i], ff.NewElement().Mul(roots.roots[bits][i], p2[i]))
out[i+ndiv2] = ff.NewElement().Sub(p1[i], ff.NewElement().Mul(roots.roots[bits][i], p2[i]))
}
return out
}
func ifft(p []*big.Int) []*big.Int {
func ifft(p []*ff.Element) []*ff.Element {
if len(p) <= 1 {
return p
}
@@ -82,20 +83,20 @@ func ifft(p []*big.Int) []*big.Int {
ep := extend(p, m)
res := fft(roots, ep, int(bits), 0, 1)
twoinvm := fInv(fMul(big.NewInt(1), big.NewInt(int64(m))))
twoinvm := ff.NewElement().SetBigInt(fInv(fMul(big.NewInt(1), big.NewInt(int64(m)))))
var resn []*big.Int
var resn []*ff.Element
for i := 0; i < m; i++ {
resn = append(resn, fMul(res[(m-i)%m], twoinvm))
resn = append(resn, ff.NewElement().Mul(res[(m-i)%m], twoinvm))
}
return resn
}
func extend(p []*big.Int, e int) []*big.Int {
func extend(p []*ff.Element, e int) []*ff.Element {
if e == len(p) {
return p
}
z := arrayOfZeroes(e - len(p))
z := arrayOfZeroesE(e - len(p))
return append(p, z...)
}

View File

@@ -6,6 +6,7 @@ import (
bn256 "github.com/ethereum/go-ethereum/crypto/bn256/cloudflare"
"github.com/iden3/go-circom-prover-verifier/types"
"github.com/iden3/go-iden3-crypto/utils"
)
// Proof is the data structure of the Groth16 zkSNARK proof
@@ -123,13 +124,18 @@ func calculateH(pk *types.Pk, w types.Witness) []*big.Int {
polCT[j] = fAdd(polCT[j], fMul(w[i], pk.PolsC[i][j]))
}
}
polAS := ifft(polAT)
polBS := ifft(polBT)
polATe := utils.BigIntArrayToElementArray(polAT)
polBTe := utils.BigIntArrayToElementArray(polBT)
polCTe := utils.BigIntArrayToElementArray(polCT)
polABS := polynomialMul(polAS, polBS)
polCS := ifft(polCT)
polABCS := polynomialSub(polABS, polCS)
polASe := ifft(polATe)
polBSe := ifft(polBTe)
polABSe := polynomialMulE(polASe, polBSe)
hS := polABCS[m:]
return hS
polCSe := ifft(polCTe)
polABCSe := polynomialSubE(polABSe, polCSe)
hSe := polABCSe[m:]
return ElementArrayToBigIntArray(hSe)
}