init: v1.0.0

tpc/sm2/sm2a/sign_server.go

@@ -0,0 +1,47 @@
+package sm2a
+
+import (
+	"io"
+	"math/big"
+
+	"xdx.jelly/xgcl/gmath"
+	"xdx.jelly/xgcl/sm/sm2"
+	"xdx.jelly/xgcl/sm/sm3"
+)
+
+// ServerSign 服务端根据客户端的协同签名中间数据计算
+// in = e || [k_1](P+G)
+// out = r || k_2 + r*d_s
+func ServerSign(serverKey *sm2.PrivateKey, pk *sm2.PublicKey, in []byte, rand io.Reader) ([]byte, error) {
+	k2 := make([]byte, sm2.ByteSize())
+	if n, err := rand.Read(k2); n != len(k2) || err != nil {
+		return nil, err
+	}
+	var x, y *big.Int
+	tx := new(big.Int)
+	ty := new(big.Int)
+	r := new(big.Int)
+	r.SetBytes(in[:sm3.Size])
+	tx.SetBytes(in[sm3.Size : sm3.Size+sm2.ByteSize()])
+	ty.SetBytes(in[sm3.Size+sm2.ByteSize() : sm3.Size+2*sm2.ByteSize()])
+	x, y = sm2.Curve().Add(pk.X, pk.Y, sm2.BaseX(), sm2.BaseY())
+	x, y = sm2.Curve256.ScalarMult(x, y, k2)
+	x, y = sm2.Curve().Add(x, y, tx, ty)
+	r.Add(r, x)
+	r.Mod(r, sm2.OrderN())
+	x.Mul(r, serverKey.D)
+	y.SetBytes(k2)
+	x.Add(x, y)
+	x.Mod(x, sm2.OrderN())
+	out := make([]byte, 2*sm2.ByteSize())
+	copy(out, gmath.BigIntToNByte(r, sm2.ByteSize()))
+	copy(out[sm2.ByteSize():], gmath.BigIntToNByte(x, sm2.ByteSize()))
+
+	// 清除中间变量
+	gmath.ClearBigInt(x)
+	gmath.ClearBigInt(y)
+	gmath.ClearBigInt(tx)
+	gmath.ClearBigInt(ty)
+	gmath.ClearBigInt(r)
+	return out, nil
+}