add generate curve utility

sei-protocol · Nov 27, 2024 · 756335b · 756335b
1 parent 258e510
commit 756335b
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Showing 6 changed files with 72 additions and 17 deletions.
diff --git a/pkg/zkproofs/ciphertext_ciphertext_equality.go b/pkg/zkproofs/ciphertext_ciphertext_equality.go
@@ -1,7 +1,6 @@
 package zkproofs
 
 import (
-	"crypto/rand"
 	"encoding/json"
 	"errors"
 
@@ -68,10 +67,19 @@ func NewCiphertextCiphertextEqualityProof(
 	r := *destinationOpening
 
 	// Generate random scalars
-	ed25519 := curves.ED25519()
-	ys := ed25519.Scalar.Random(rand.Reader)
-	yx := ed25519.Scalar.Random(rand.Reader)
-	yr := ed25519.Scalar.Random(rand.Reader)
+	curve := curves.ED25519()
+	ys, err := GenerateRandomScalar(curve)
+	if err != nil {
+		return nil, err
+	}
+	yx, err := GenerateRandomScalar(curve)
+	if err != nil {
+		return nil, err
+	}
+	yr, err := GenerateRandomScalar(curve)
+	if err != nil {
+		return nil, err
+	}
 
 	eg := elgamal.NewTwistedElgamal()
 	G := eg.GetG()

diff --git a/pkg/zkproofs/ciphertext_commitment_equality.go b/pkg/zkproofs/ciphertext_commitment_equality.go
@@ -1,7 +1,6 @@
 package zkproofs
 
 import (
-	"crypto/rand"
 	"encoding/json"
 	"errors"
 
@@ -60,11 +59,22 @@ func NewCiphertextCommitmentEqualityProof(
 	G := eg.GetG() // Fixed base point G
 	H := eg.GetH() // Fixed base point H
 
-	ed25519 := curves.ED25519()
 	// Generate random masking factors
-	ys := ed25519.Scalar.Random(rand.Reader)
-	yx := ed25519.Scalar.Random(rand.Reader)
-	yr := ed25519.Scalar.Random(rand.Reader)
+	curve := curves.ED25519()
+	ys, err := GenerateRandomScalar(curve)
+	if err != nil {
+		return nil, err
+	}
+
+	yx, err := GenerateRandomScalar(curve)
+	if err != nil {
+		return nil, err
+	}
+
+	yr, err := GenerateRandomScalar(curve)
+	if err != nil {
+		return nil, err
+	}
 
 	// Compute Y0 = ys * P
 	Y0 := P.Mul(ys)

diff --git a/pkg/zkproofs/ciphertext_validity.go b/pkg/zkproofs/ciphertext_validity.go
@@ -1,7 +1,6 @@
 package zkproofs
 
 import (
-	crand "crypto/rand"
 	"encoding/json"
 	"errors"
 	"math/big"
@@ -48,8 +47,16 @@ func NewCiphertextValidityProof(pedersenOpening *curves.Scalar, pubKey curves.Po
 	x, _ := ed25519.Scalar.SetBigInt(message)
 
 	// Step 1: Generate random blinding factors for the proof
-	rBlind := ed25519.Scalar.Random(crand.Reader) // Blinding factor for random value r
-	xBlind := ed25519.Scalar.Random(crand.Reader) // Blinding factor for random value x
+	curve := curves.ED25519()
+	rBlind, err := GenerateRandomScalar(curve) // Blinding factor for random value r
+	if err != nil {
+		return nil, err
+	}
+
+	xBlind, err := GenerateRandomScalar(curve) // Blinding factor for random value x
+	if err != nil {
+		return nil, err
+	}
 
 	// Step 2: Create commitments
 	rBlindH := H.Mul(rBlind)            // rBlind * H

diff --git a/pkg/zkproofs/pubkey_validity.go b/pkg/zkproofs/pubkey_validity.go
@@ -1,7 +1,6 @@
 package zkproofs
 
 import (
-	"crypto/rand"
 	"encoding/json"
 	"errors"
 
@@ -37,8 +36,13 @@ func NewPubKeyValidityProof(pubKey curves.Point, privKey curves.Scalar) (*PubKey
 
 	eg := elgamal.NewTwistedElgamal()
 	H := eg.GetH()
+
 	// Prover generates a random scalar y
-	y := curves.ED25519().Scalar.Random(rand.Reader)
+	curve := curves.ED25519()
+	y, err := GenerateRandomScalar(curve)
+	if err != nil {
+		return nil, err
+	}
 
 	// Commitment Y = y * H
 	Y := H.Mul(y)

diff --git a/pkg/zkproofs/utils.go b/pkg/zkproofs/utils.go
@@ -0,0 +1,23 @@
+package zkproofs
+
+import (
+	"crypto/rand"
+	"errors"
+
+	"github.com/coinbase/kryptology/pkg/core/curves"
+)
+
+func GenerateRandomScalar(curve *curves.Curve) (curves.Scalar, error) {
+	attempts := 0
+	scalar := curve.Scalar.Random(rand.Reader)
+	for scalar.IsZero() && attempts < 5 {
+		curve.Scalar.Random(rand.Reader)
+		attempts += 1
+	}
+
+	if scalar.IsZero() {
+		return nil, errors.New("failed to generate a non-zero scalar")
+	}
+
+	return scalar, nil
+}
diff --git a/pkg/zkproofs/zero_balance.go b/pkg/zkproofs/zero_balance.go
@@ -1,7 +1,6 @@
 package zkproofs
 
 import (
-	"crypto/rand"
 	"encoding/json"
 	"errors"
 
@@ -38,7 +37,11 @@ func NewZeroBalanceProof(
 	D := ciphertext.D
 
 	// Generate random masking factor y
-	y := curves.ED25519().Scalar.Random(rand.Reader)
+	curve := curves.ED25519()
+	y, err := GenerateRandomScalar(curve)
+	if err != nil {
+		return nil, err
+	}
 
 	// Compute Yp = y * P and Yd = y * D
 	Yp := P.Mul(y)