init: v1.0.0

sm/sm9/dkgc/sign.go

@@ -0,0 +1,106 @@
+package dkgc
+
+import (
+	"crypto/rand"
+	"io"
+	"math/big"
+
+	"xdx.jelly/xgcl/sm/sm9"
+)
+
+type ServerKey struct {
+	big.Int
+}
+
+type ClientKey = sm9.UserSignKey
+
+func ServerGenerateKey(r io.Reader) (sk *ServerKey, basePoint *ClientKey, err error) {
+	for {
+		x, err := rand.Int(r, sm9.Order())
+		if err != nil {
+			return nil, nil, err
+		}
+		if x.Sign() == 0 {
+			continue
+		}
+		sk = &ServerKey{
+			Int: *x,
+		}
+		basePoint = &ClientKey{}
+		y := new(big.Int).Set(x)
+		y.ModInverse(y, sm9.Order())
+		basePoint.G1.ScalarBaseMult(y)
+		return sk, basePoint, nil
+	}
+}
+
+type ClientSignContext struct {
+	r1 big.Int
+}
+
+func (csc *ClientSignContext) ComputeSignData(r io.Reader, pubs *sm9.MastSignPublicKey) (u *sm9.GT, err error) {
+	for {
+		x, err := rand.Int(r, sm9.Order())
+		if err != nil {
+			return nil, err
+		}
+		if x.Sign() == 0 {
+			continue
+		}
+		csc.r1 = *x
+		break
+	}
+	u = sm9.Pairing(sm9.G1Generator(), &pubs.G2)
+	u.ScalarMult(u, &csc.r1)
+	return u, nil
+}
+
+func (csc *ClientSignContext) ComputeSignature(id []byte, h, k1, k2 *big.Int, kc *ClientKey) (*sm9.Signature, error) {
+	sig := &sm9.Signature{}
+	sig.H = *h
+	x := new(big.Int)
+	x.Mul(&csc.r1, k1)
+	x.Add(x, k2)
+	sig.S.ScalarMult(&kc.G1, x)
+	return sig, nil
+}
+
+func ServerComputeSignData(r io.Reader, u *sm9.GT, m []byte, pubs *sm9.MastSignPublicKey, ks *ServerKey) (h, k1, k2 *big.Int, err error) {
+	r2 := new(big.Int)
+	r3 := new(big.Int)
+	for {
+		r2, err = rand.Int(r, sm9.Order())
+		if err != nil {
+			return nil, nil, nil, err
+		}
+		if r2.Sign() == 0 {
+			continue
+		}
+		break
+	}
+
+	for {
+		r3, err = rand.Int(r, sm9.Order())
+		if err != nil {
+			return nil, nil, nil, err
+		}
+		if r3.Sign() == 0 {
+			continue
+		}
+		break
+	}
+
+	g := sm9.Pairing(sm9.G1Generator(), &pubs.G2)
+	g.ScalarMult(g, r3)
+	w := new(sm9.GT)
+	w.ScalarMult(u, r2)
+	w.Add(w, g)
+	h = sm9.H2(m, w.Marshal())
+
+	k1 = new(big.Int).Mul(r2, &ks.Int)
+	k1.Mod(k1, sm9.Order())
+	k2 = new(big.Int).Sub(r3, h)
+	k2.Mul(k2, &ks.Int)
+	k2.Mod(k2, sm9.Order())
+	return h, k1, k2, nil
+}