feat: add groth16 commitment verifier (#2)

* feat: add groth16 commitment verifier

* remove --via-ir after optimizations

* refactor: merge commit/no-commit Groth16 templates

* chore: update template go.mod

---------

Co-authored-by: Ivo Kubjas <ivo.kubjas@consensys.net>

cmd/templates.go

@@ -43,9 +43,11 @@ func main() {
 	proofBytes, err := hex.DecodeString(proofHex)
 	checkErr(err, "decode proof hex failed")
 
+	{{ if eq .NbCommitments 0 }}
 	if len(proofBytes) != fpSize*8 {
 		panic("proofBytes != fpSize*8")
 	}
+	{{ end }}
 
 	inputBytes, err := hex.DecodeString(inputHex)
 	checkErr(err, "decode input hex failed")
@@ -75,6 +77,7 @@ func main() {
 		proof[i] = new(big.Int).SetBytes(proofBytes[fpSize*i : fpSize*(i+1)])
 	}
 
+	{{ if eq .NbCommitments 0 }}
 	// call the contract
 	err = verifierContract.VerifyProof(&bind.CallOpts{}, proof, input)
 	checkErr(err, "calling verifier on chain gave error")
@@ -86,6 +89,39 @@ func main() {
 	// verify compressed proof
 	err = verifierContract.VerifyCompressedProof(&bind.CallOpts{}, proofCompressed, input)
 	checkErr(err, "calling verifier with compressed proof on chain gave error")
+	{{ else }}
+	// prepare commitments for calling
+	c := new(big.Int).SetBytes(proofBytes[fpSize*8 : fpSize*8+4])
+	commitmentCount := int(c.Int64())
+
+	if commitmentCount != {{ .NbCommitments }} {
+		panic("commitmentCount != .NbCommitments")
+	}
+
+	var commitments [{{mul 2 .NbCommitments}}]*big.Int
+	var commitmentPok [2]*big.Int
+
+	// commitments
+	for i := 0; i < 2*commitmentCount; i++ {
+		commitments[i] = new(big.Int).SetBytes(proofBytes[fpSize*8+4+i*fpSize : fpSize*8+4+(i+1)*fpSize])
+	}
+
+	// commitmentPok
+	commitmentPok[0] = new(big.Int).SetBytes(proofBytes[fpSize*8+4+2*commitmentCount*fpSize : fpSize*8+4+2*commitmentCount*fpSize+fpSize])
+	commitmentPok[1] = new(big.Int).SetBytes(proofBytes[fpSize*8+4+2*commitmentCount*fpSize+fpSize : fpSize*8+4+2*commitmentCount*fpSize+2*fpSize])
+
+	// call the contract
+	err = verifierContract.VerifyProof(&bind.CallOpts{}, proof, commitments, commitmentPok, input)
+	checkErr(err, "calling verifier on chain gave error")
+
+	// compress proof
+	compressed, err := verifierContract.CompressProof(&bind.CallOpts{}, proof, commitments, commitmentPok)
+	checkErr(err, "compressing proof gave error")
+
+	// verify compressed proof
+	err = verifierContract.VerifyCompressedProof(&bind.CallOpts{}, compressed.Compressed, compressed.CompressedCommitments, compressed.CompressedCommitmentPok, input)
+	checkErr(err, "calling verifier with compressed proof on chain gave error")
+	{{ end }}
 }
 
 func checkErr(err error, ctx string) {
@@ -188,8 +224,8 @@ const tmplGoMod = `module tmpsolidity
 go 1.20
 
 require (
-	github.com/consensys/gnark v0.7.2-0.20230620210714-0713c1dc4def
-	github.com/consensys/gnark-crypto v0.11.1-0.20230609175512-0ee617fa6d43
+	github.com/consensys/gnark v0.9.2-0.20240401222041-3b3c1e89a35f
+	github.com/consensys/gnark-crypto v0.12.2-0.20240215234832-d72fcb379d3e
 	github.com/ethereum/go-ethereum v1.12.0
 )
 

cmd/verify.go

@@ -19,6 +19,7 @@ var (
 	fNbPublicInputs int    // number of public inputs
 	fGroth16        bool
 	fPlonK          bool
+	fNbCommitments  int // number of commitments
 )
 
 // verifyCmd represents the verify command
@@ -36,20 +37,20 @@ func runVerify(cmd *cobra.Command, args []string) {
 		os.Exit(1)
 	}
 
-	if fGroth16 {
-		if err := generateMain(tmplGroth16, filepath.Join(fBaseDir, "main.go"), fProof, fPublicInputs, fNbPublicInputs); err != nil {
-			fmt.Println(err)
-			os.Exit(1)
-		}
-	} else if fPlonK {
-		if err := generateMain(tmplPlonK, filepath.Join(fBaseDir, "main.go"), fProof, fPublicInputs, fNbPublicInputs); err != nil {
-			fmt.Println(err)
-			os.Exit(1)
-		}
-	} else {
+	var tmpl string
+	switch {
+	case fGroth16:
+		tmpl = tmplGroth16
+	case fPlonK:
+		tmpl = tmplPlonK
+	default:
 		fmt.Println("please specify either --groth16 or --plonk")
 		os.Exit(1)
 	}
+	if err := generateMain(tmpl, filepath.Join(fBaseDir, "main.go"), fProof, fPublicInputs, fNbPublicInputs, fNbCommitments); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
 
 	// generate go.mod file
 	if err := generateGoMod(filepath.Join(fBaseDir, "go.mod")); err != nil {
@@ -97,7 +98,7 @@ func generateGoMod(filename string) error {
 	return tmpl.Execute(f, nil)
 }
 
-func generateMain(tmplStr, filename, proof, publicInputs string, nbPublicInputs int) error {
+func generateMain(tmplStr, filename, proof, publicInputs string, nbPublicInputs, fNbCommitments int) error {
 	fmt.Println("generating " + filename)
 	f, err := os.Create(filename)
 	if err != nil {
@@ -106,7 +107,13 @@ func generateMain(tmplStr, filename, proof, publicInputs string, nbPublicInputs
 	}
 	defer f.Close()
 
-	tmpl, err := template.New("").Parse(tmplStr)
+	helpers := template.FuncMap{
+		"mul": func(a, b int) int {
+			return a * b
+		},
+	}
+
+	tmpl, err := template.New("").Funcs(helpers).Parse(tmplStr)
 	if err != nil {
 		return err
 	}
@@ -115,10 +122,12 @@ func generateMain(tmplStr, filename, proof, publicInputs string, nbPublicInputs
 		Proof          string
 		PublicInputs   string
 		NbPublicInputs int
+		NbCommitments  int
 	}{
 		Proof:          proof,
 		PublicInputs:   publicInputs,
 		NbPublicInputs: nbPublicInputs,
+		NbCommitments:  fNbCommitments,
 	}
 
 	// execute template
@@ -141,4 +150,6 @@ func init() {
 	verifyCmd.Flags().BoolVar(&fPlonK, "plonk", false, "use plonk verification")
 
 	verifyCmd.MarkFlagsMutuallyExclusive("groth16", "plonk")
+
+	verifyCmd.Flags().IntVar(&fNbCommitments, "commitment", 0, "number of commitments in proof")
 }