extract secp256k1 to own repo

.github/.golangci.yml

@@ -18,7 +18,7 @@ linters:
     - errname
     - errorlint
     - execinquery
-    - exhaustive
+    #- exhaustive
     - exhaustruct
     - exportloopref
     - forbidigo
@@ -29,7 +29,7 @@ linters:
     #- gochecknoinits
     - gocognit
     - goconst
-    #- gocritic
+    - gocritic
     - gocyclo
     - godot
     - godox
@@ -130,6 +130,8 @@ linters-settings:
       - opinionated
       - performance
       - style
+    disabled-checks:
+      - commentedOutCode
   gocyclo:
     min-complexity: 15
   godox:

go.mod

@@ -5,12 +5,13 @@ go 1.20
 require (
 	filippo.io/edwards25519 v1.0.0
 	filippo.io/nistec v0.0.2
-	github.com/bytemare/hash2curve v0.1.3
+	github.com/bytemare/hash2curve v0.2.2
+	github.com/bytemare/secp256k1 v0.0.0-20230421210201-f2244bd0effa
 	github.com/gtank/ristretto255 v0.1.2
 )
 
 require (
 	github.com/bytemare/hash v0.1.5 // indirect
-	golang.org/x/crypto v0.7.0 // indirect
-	golang.org/x/sys v0.6.0 // indirect
+	golang.org/x/crypto v0.8.0 // indirect
+	golang.org/x/sys v0.7.0 // indirect
 )

go.sum

@@ -4,11 +4,13 @@ filippo.io/nistec v0.0.2 h1:/NIXTUimcHIh0E2DsYucHlICvUisgj28/XEnKSEptUs=
 filippo.io/nistec v0.0.2/go.mod h1:84fxC9mi+MhC2AERXI4LSa8cmSVOzrFikg6hZ4IfCyw=
 github.com/bytemare/hash v0.1.5 h1:VW+X1YQ2b3chjRFHkRUnO42uclsQjXimdBCPOgIobR4=
 github.com/bytemare/hash v0.1.5/go.mod h1:+QmWXTky/2b63ngqM5IYezGydn9UTFDhpX7mLYwYxCA=
-github.com/bytemare/hash2curve v0.1.3 h1:BOqV8BF5dF+BbPZgIyoeAVTwd4m7jmw4LwacD1GFBvU=
-github.com/bytemare/hash2curve v0.1.3/go.mod h1:Wma3DmJdn8kqiK9j120hkWvC3tQVKS1PyA8ZzyG23BI=
+github.com/bytemare/hash2curve v0.2.2 h1:zaGx6Z4/N4Pl9B7aGNtpbZ09vu1NNJGoJRRtHHl8oTw=
+github.com/bytemare/hash2curve v0.2.2/go.mod h1:Wma3DmJdn8kqiK9j120hkWvC3tQVKS1PyA8ZzyG23BI=
+github.com/bytemare/secp256k1 v0.0.0-20230421210201-f2244bd0effa h1:vrXhOGi25aItUpmJo1ItTZhcv5L7U9/1vdcxL+pKa88=
+github.com/bytemare/secp256k1 v0.0.0-20230421210201-f2244bd0effa/go.mod h1:hzquMsr3GXhVcqL9qFX7GGjmcT5dlQldKrArd7tcXHE=
 github.com/gtank/ristretto255 v0.1.2 h1:JEqUCPA1NvLq5DwYtuzigd7ss8fwbYay9fi4/5uMzcc=
 github.com/gtank/ristretto255 v0.1.2/go.mod h1:Ph5OpO6c7xKUGROZfWVLiJf9icMDwUeIvY4OmlYW69o=
-golang.org/x/crypto v0.7.0 h1:AvwMYaRytfdeVt3u6mLaxYtErKYjxA2OXjJ1HHq6t3A=
-golang.org/x/crypto v0.7.0/go.mod h1:pYwdfH91IfpZVANVyUOhSIPZaFoJGxTFbZhFTx+dXZU=
-golang.org/x/sys v0.6.0 h1:MVltZSvRTcU2ljQOhs94SXPftV6DCNnZViHeQps87pQ=
-golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/crypto v0.8.0 h1:pd9TJtTueMTVQXzk8E2XESSMQDj/U7OUu0PqJqPXQjQ=
+golang.org/x/crypto v0.8.0/go.mod h1:mRqEX+O9/h5TFCrQhkgjo2yKi0yYA+9ecGkdQoHrywE=
+golang.org/x/sys v0.7.0 h1:3jlCCIQZPdOYu1h8BkNvLz8Kgwtae2cagcG/VamtZRU=
+golang.org/x/sys v0.7.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

groups.go

@@ -169,8 +169,6 @@ func (g Group) init() {
 		g.initGroup(edwards25519.New)
 	case Secp256k1:
 		g.initGroup(secp256k1.New)
-	case maxID:
-		fallthrough
 	default:
 		panic("group not recognized")
 	}

internal/field/field.go

@@ -29,12 +29,12 @@ func String2Int(s string) big.Int {
 	panic("invalid string to convert")
 }
 
-// Field represents a Gaulois Field.
+// Field represents a Galois Field.
 type Field struct {
-	order       big.Int
-	pMinus1div2 big.Int // used in IsSquare
-	pMinus2     big.Int // used for Field big.Int inversion
-	exp         big.Int
+	order       *big.Int
+	pMinus1div2 *big.Int // used in IsSquare
+	pMinus2     *big.Int // used for Field big.Int inversion
+	exp         *big.Int
 }
 
 // NewField returns a newly instantiated field for the given prime order.
@@ -54,10 +54,10 @@ func NewField(prime *big.Int) Field {
 	exp.Rsh(exp, 2)
 
 	return Field{
-		order:       *prime,
-		pMinus1div2: *pMinus1div2,
-		pMinus2:     *pMinus2,
-		exp:         *exp,
+		order:       prime,
+		pMinus1div2: pMinus1div2,
+		pMinus2:     pMinus2,
+		exp:         exp,
 	}
 }
 
@@ -73,7 +73,7 @@ func (f Field) One() *big.Int {
 
 // Random sets res to a random big.Int in the Field.
 func (f Field) Random(res *big.Int) *big.Int {
-	tmp, err := rand.Int(rand.Reader, &f.order)
+	tmp, err := rand.Int(rand.Reader, f.order)
 	if err != nil {
 		// We can as well not panic and try again in a loop
 		panic(fmt.Errorf("unexpected error in generating random bytes : %w", err))
@@ -86,7 +86,7 @@ func (f Field) Random(res *big.Int) *big.Int {
 
 // Order returns the size of the Field.
 func (f Field) Order() *big.Int {
-	return &f.order
+	return f.order
 }
 
 // BitLen of the order.
@@ -106,18 +106,18 @@ func (f Field) IsZero(e *big.Int) bool {
 
 // Inv sets res to the modular inverse of x mod field order.
 func (f Field) Inv(res, x *big.Int) {
-	f.Exponent(res, x, &f.pMinus2)
+	f.Exponent(res, x, f.pMinus2)
 }
 
 // LegendreSymbol applies the Legendre symbole on (a/p) and returns either {-1, 0, 1} mod field order.
 func (f Field) LegendreSymbol(a *big.Int) *big.Int {
 	var res big.Int
-	return f.Exponent(&res, a, &f.pMinus1div2)
+	return f.Exponent(&res, a, f.pMinus1div2)
 }
 
 // Exponent returns x^n mod field order.
 func (f Field) Exponent(res, x, n *big.Int) *big.Int {
-	return res.Exp(x, n, &f.order)
+	return res.Exp(x, n, f.order)
 }
 
 // IsSquare returns whether e is a quadratic square.
@@ -127,12 +127,12 @@ func (f Field) IsSquare(e *big.Int) bool {
 
 // IsEqual returns whether the two fields have the same order.
 func (f Field) IsEqual(f2 *Field) bool {
-	return f.order.Cmp(&f2.order) == 0
+	return f.order.Cmp(f2.order) == 0
 }
 
 // Mod reduces x modulo the field order.
 func (f Field) Mod(x *big.Int) *big.Int {
-	return x.Mod(x, &f.order)
+	return x.Mod(x, f.order)
 }
 
 // Neg sets res to the -x modulo the field order.
@@ -193,7 +193,7 @@ func (f Field) Sgn0(x *big.Int) int {
 }
 
 func (f Field) sqrt3mod4(res, e *big.Int) *big.Int {
-	return f.Exponent(res, e, &f.exp)
+	return f.Exponent(res, e, f.exp)
 }
 
 // SquareRoot sets res to a square root of e mod the field's order, if such a square root exists.

internal/nist/scalar.go

@@ -23,9 +23,9 @@ type Scalar struct {
 	scalar big.Int
 }
 
-func newScalar(field *field.Field) *Scalar {
+func newScalar(f *field.Field) *Scalar {
 	s := &Scalar{
-		field:  field,
+		field:  f,
 		scalar: big.Int{},
 	}
 	s.scalar.Set(s.field.Zero())