small update, fix trusted setup ops over Field R

README.md

@@ -7,7 +7,7 @@ zkSNARK library implementation in Go
 - `Pinocchio: Nearly practical verifiable computation`, Bryan Parno, Craig Gentry, Jon Howell, Mariana Raykova https://eprint.iacr.org/2013/279.pdf
 
 ## Caution
-Implementation from scratch in Go to understand the concepts. Do not use in production.
+Implementation of the zkSNARK [Pinocchio protocol](https://eprint.iacr.org/2013/279.pdf) from scratch in Go to understand the concepts. Do not use in production.
 
 Not finished, implementing this in my free time to understand it better, so I don't have much time.
 
@@ -15,17 +15,18 @@ Current implementation status:
 - [x] Finite Fields (1, 2, 6, 12) operations
 - [x] G1 and G2 curve operations
 - [x] BN128 Pairing
-- [x] circuit code compiler
+- [ ] circuit code compiler
 	- [ ] code to flat code (improve circuit compiler)
 	- [x] flat code compiler
+	- [ ] private & public inputs. fix circuit compiler
 - [x] circuit to R1CS
 - [x] polynomial operations
 - [x] R1CS to QAP
 - [x] generate trusted setup
 - [x] generate proofs
 - [x] verify proofs with BN128 pairing
-	- [ ] fix 4th pairing proofs generation & verification: ê(Vkx+piA, piB) == ê(piH, Vkz) * ê(piC, g2)
+	- [ ] fix 4th pairing proofs generation & verification: ê(Vkx+piA, piB) == ê(piH, Vkz) * ê(piC, G2)
-- [ ] WASM implementation to run on browsers
+- [ ] move witness calculation outside the setup phase
 
 
 ## Usage

r1csqap/r1csqap.go

@@ -189,24 +189,24 @@ func (pf PolynomialField) R1CSToQAP(a, b, c [][]*big.Int) ([][]*big.Int, [][]*bi
 
 // CombinePolynomials combine the given polynomials arrays into one, also returns the P(x)
 func (pf PolynomialField) CombinePolynomials(r []*big.Int, ap, bp, cp [][]*big.Int) ([]*big.Int, []*big.Int, []*big.Int, []*big.Int) {
-	var alpha []*big.Int
+	var ax []*big.Int
 	for i := 0; i < len(r); i++ {
 		m := pf.Mul([]*big.Int{r[i]}, ap[i])
-		alpha = pf.Add(alpha, m)
+		ax = pf.Add(ax, m)
 	}
-	var beta []*big.Int
+	var bx []*big.Int
 	for i := 0; i < len(r); i++ {
 		m := pf.Mul([]*big.Int{r[i]}, bp[i])
-		beta = pf.Add(beta, m)
+		bx = pf.Add(bx, m)
 	}
-	var gamma []*big.Int
+	var cx []*big.Int
 	for i := 0; i < len(r); i++ {
 		m := pf.Mul([]*big.Int{r[i]}, cp[i])
-		gamma = pf.Add(gamma, m)
+		cx = pf.Add(cx, m)
 	}
 
-	px := pf.Sub(pf.Mul(alpha, beta), gamma)
+	px := pf.Sub(pf.Mul(ax, bx), cx)
-	return alpha, beta, gamma, px
+	return ax, bx, cx, px
 }
 
 // DivisorPolynomial returns the divisor polynomial given two polynomials

snark.go

@@ -99,13 +99,15 @@ func GenerateTrustedSetup(witnessLength int, circuit circuitcompiler.Circuit, al
 	for i := 0; i < len(alphas); i++ {
 		for j := 0; j < len(alphas[i]); j++ {
 			if j <= circuit.NPublic {
-				if bytes.Equal(alphas[i][j].Bytes(), Utils.Bn.Fq1.Zero().Bytes()) {
+				if bytes.Equal(alphas[i][j].Bytes(), Utils.FqR.Zero().Bytes()) {
-					alphas[i][j] = Utils.Bn.Fq1.One()
+					alphas[i][j] = Utils.FqR.One()
 				}
 			}
 		}
 	}
 
+	fmt.Println("alphas[1]", alphas[1])
+
 	// generate random t value
 	setup.Toxic.T, err = Utils.FqR.Rand()
 	if err != nil {
@@ -176,7 +178,8 @@ func GenerateTrustedSetup(witnessLength int, circuit circuitcompiler.Circuit, al
 	// for i := 0; i < circuit.NVars; i++ {
 	for i := 0; i < len(circuit.Signals); i++ {
 		at := Utils.PF.Eval(alphas[i], setup.Toxic.T)
-		rhoAat := Utils.Bn.Fq1.Mul(setup.Toxic.RhoA, at)
+		// rhoAat := Utils.Bn.Fq1.Mul(setup.Toxic.RhoA, at)
+		rhoAat := Utils.FqR.Mul(setup.Toxic.RhoA, at)
 		a := Utils.Bn.G1.MulScalar(Utils.Bn.G1.G, rhoAat)
 		setup.Pk.A = append(setup.Pk.A, a)
 		if i <= circuit.NPublic {
@@ -184,13 +187,15 @@ func GenerateTrustedSetup(witnessLength int, circuit circuitcompiler.Circuit, al
 		}
 
 		bt := Utils.PF.Eval(betas[i], setup.Toxic.T)
-		rhoBbt := Utils.Bn.Fq1.Mul(setup.Toxic.RhoB, bt)
+		// rhoBbt := Utils.Bn.Fq1.Mul(setup.Toxic.RhoB, bt)
+		rhoBbt := Utils.FqR.Mul(setup.Toxic.RhoB, bt)
 		bg1 := Utils.Bn.G1.MulScalar(Utils.Bn.G1.G, rhoBbt)
 		bg2 := Utils.Bn.G2.MulScalar(Utils.Bn.G2.G, rhoBbt)
 		setup.Pk.B = append(setup.Pk.B, bg2)
 
 		ct := Utils.PF.Eval(gammas[i], setup.Toxic.T)
-		rhoCct := Utils.Bn.Fq1.Mul(setup.Toxic.RhoC, ct)
+		// rhoCct := Utils.Bn.Fq1.Mul(setup.Toxic.RhoC, ct)
+		rhoCct := Utils.FqR.Mul(setup.Toxic.RhoC, ct)
 		c := Utils.Bn.G1.MulScalar(Utils.Bn.G1.G, rhoCct)
 		setup.Pk.C = append(setup.Pk.C, c)
 
@@ -212,8 +217,7 @@ func GenerateTrustedSetup(witnessLength int, circuit circuitcompiler.Circuit, al
 
 	// z pol
 	zpol := []*big.Int{big.NewInt(int64(1))}
-	// for i := 1; i < len(circuit.Constraints); i++ {
+	for i := 1; i < len(circuit.Constraints); i++ {
-	for i := 1; i <= circuit.NPublic; i++ { // circuit.NPublic == d
 		zpol = Utils.PF.Mul(
 			zpol,
 			[]*big.Int{
@@ -222,10 +226,12 @@ func GenerateTrustedSetup(witnessLength int, circuit circuitcompiler.Circuit, al
 				big.NewInt(int64(1)),
 			})
 	}
+	fmt.Println("zpol", zpol)
 	setup.Pk.Z = zpol
 
 	zt := Utils.PF.Eval(zpol, setup.Toxic.T)
-	rhoCzt := Utils.Bn.Fq1.Mul(setup.Toxic.RhoC, zt)
+	// rhoCzt := Utils.Bn.Fq1.Mul(setup.Toxic.RhoC, zt)
+	rhoCzt := Utils.FqR.Mul(setup.Toxic.RhoC, zt)
 	setup.Vk.Vkz = Utils.Bn.G2.MulScalar(Utils.Bn.G2.G, rhoCzt)
 
 	// encrypt t values with curve generators
@@ -234,7 +240,8 @@ func GenerateTrustedSetup(witnessLength int, circuit circuitcompiler.Circuit, al
 	tEncr := setup.Toxic.T
 	for i := 1; i < len(zpol); i++ { //should be G1T = pkH = (tau**i * G1) from i=0 to d, where d is degree of pol Z(x)
 		gt1 = append(gt1, Utils.Bn.G1.MulScalar(Utils.Bn.G1.G, tEncr))
-		tEncr = Utils.Bn.Fq1.Mul(tEncr, setup.Toxic.T)
+		// tEncr = Utils.Bn.Fq1.Mul(tEncr, setup.Toxic.T)
+		tEncr = Utils.FqR.Mul(tEncr, setup.Toxic.T)
 	}
 	fmt.Println("len(G1T)", len(gt1))
 	setup.G1T = gt1
@@ -272,8 +279,8 @@ func GenerateProofs(circuit circuitcompiler.Circuit, setup Setup, w []*big.Int,
 	hx := Utils.PF.DivisorPolynomial(px, setup.Pk.Z) // maybe move this calculation to a previous step
 
 	// piH = pkH,0 + sum (  hi * pk H,i ), where pkH = G1T, hi=hx
-	proof.PiH = Utils.Bn.G1.Add(proof.PiH, setup.G1T[0])
+	// proof.PiH = Utils.Bn.G1.Add(proof.PiH, setup.G1T[0])
-	for i := 1; i < len(setup.Pk.Z); i++ {
+	for i := 0; i < len(hx); i++ {
 		proof.PiH = Utils.Bn.G1.Add(proof.PiH, Utils.Bn.G1.MulScalar(setup.G1T[i], hx[i]))
 	}
 

snark_test.go

@@ -50,10 +50,11 @@ func TestZkFromFlatCircuitCode(t *testing.T) {
 	fmt.Println("c:", c)
 
 	// R1CS to QAP
+	// TODO zxQAP is not used and is an old impl, bad calculated. TODO remove
 	alphas, betas, gammas, zxQAP := Utils.PF.R1CSToQAP(a, b, c)
 	fmt.Println("qap")
 	fmt.Println("alphas", len(alphas))
-	fmt.Println("alphas", alphas[0])
+	fmt.Println("alphas[1]", alphas[1])
 	fmt.Println("betas", len(betas))
 	fmt.Println("gammas", len(gammas))
 	fmt.Println("zx length", len(zxQAP))
@@ -63,6 +64,10 @@ func TestZkFromFlatCircuitCode(t *testing.T) {
 	fmt.Println("bx length", len(bx))
 	fmt.Println("cx length", len(cx))
 	fmt.Println("px length", len(px))
+	fmt.Println("px[last]", px[0])
+	px0 := Utils.PF.F.Add(px[0], big.NewInt(int64(88)))
+	fmt.Println(px0)
+	assert.Equal(t, px0.Bytes(), Utils.PF.F.Zero().Bytes())
 
 	hxQAP := Utils.PF.DivisorPolynomial(px, zxQAP)
 	fmt.Println("hx length", len(hxQAP))
@@ -92,15 +97,18 @@ func TestZkFromFlatCircuitCode(t *testing.T) {
 	hx := Utils.PF.DivisorPolynomial(px, setup.Pk.Z)
 	fmt.Println("hx pk.z", hx)
 	// assert.Equal(t, hxQAP, hx)
+
 	assert.Equal(t, px, Utils.PF.Mul(hxQAP, zxQAP))
+	// hx==px/zx so px==hx*zx
 	assert.Equal(t, px, Utils.PF.Mul(hx, setup.Pk.Z))
 
+	// check length of polynomials H(x) and Z(x)
 	assert.Equal(t, len(hx), len(px)-len(setup.Pk.Z)+1)
 	assert.Equal(t, len(hxQAP), len(px)-len(zxQAP)+1)
+
 	// fmt.Println("pk.Z", len(setup.Pk.Z))
 	// fmt.Println("zxQAP", len(zxQAP))
 
-	// piA = g1 * A(t), piB = g2 * B(t), piC = g1 * C(t), piH = g1 * H(t)
 	proof, err := GenerateProofs(*circuit, setup, w, px)
 	assert.Nil(t, err)