init: v1.0.0

tpc/sm9/sm9m/dec.go

@@ -0,0 +1,80 @@
+package sm9m
+
+import (
+	"encoding"
+
+	"xdx.jelly/xgcl/sm/sm9"
+)
+
+type ClientDecContext struct {
+	cipher *sm9.Cipher
+}
+
+type ClientDecParam struct {
+	c1 sm9.G1 // cipher.C1
+}
+
+type ServerDecParam struct {
+	e sm9.GT // e(C, Ks)
+}
+
+func (ctx *ClientDecContext) GenerateParam(c *sm9.Cipher) (*ClientDecParam, error) {
+	if !c.C1.IsValid() {
+		return nil, ErrInvalidCipherC1
+	}
+	ctx.cipher = c
+	param := &ClientDecParam{}
+	param.c1.Set(&c.C1)
+	return param, nil
+}
+
+func (ctx *ClientDecContext) DecryptFinal(id []byte, clientEncKey *EncKeyClient, param *ServerDecParam) ([]byte, error) {
+	w := sm9.Pairing(&ctx.cipher.C1, &clientEncKey.p)
+	w.Mul(w, &param.e) // e = e(C1, de)
+
+	c := ctx.cipher
+	keylen, f, err := sm9.DecryptParams(c)
+	if err != nil {
+		return nil, err
+	}
+	key := make([]byte, keylen)
+	_ = sm9.Kdf(key, c.C1.Marshal(), w.Marshal(), id)
+	return sm9.DecodeCipher(c, key, f)
+}
+
+func ServerDecrypt(clientParam *ClientDecParam, serverEncKey *EncKeyServer) (*ServerDecParam, error) {
+	if !clientParam.c1.IsValid() {
+		return nil, ErrInvalidCipherC1
+	}
+
+	w := sm9.Pairing(&clientParam.c1, &serverEncKey.p)
+	return &ServerDecParam{e: *w}, nil
+}
+
+var _ encoding.BinaryMarshaler = &ClientDecParam{}
+var _ encoding.BinaryUnmarshaler = &ClientDecParam{}
+
+var _ encoding.BinaryMarshaler = &ServerDecParam{}
+var _ encoding.BinaryUnmarshaler = &ServerDecParam{}
+
+// MarshalBinary implements encoding.BinaryMarshaler
+func (p *ClientDecParam) MarshalBinary() (data []byte, err error) {
+	return p.c1.Marshal(), nil
+}
+
+// UnmarshalBinary implements encoding.BinaryUnmarshaler
+func (p *ClientDecParam) UnmarshalBinary(data []byte) error {
+	_, err := p.c1.Unmarshal(data)
+	return err
+}
+
+// MarshalBinary implements encoding.BinaryMarshaler
+func (p *ServerDecParam) MarshalBinary() (data []byte, err error) {
+	return p.e.Marshal(), nil
+}
+
+// UnmarshalBinary implements encoding.BinaryUnmarshaler
+func (p *ServerDecParam) UnmarshalBinary(data []byte) error {
+	_, err := p.e.Unmarshal(data)
+	return err
+}