payload almost done

payload/metadata.go

@@ -0,0 +1,37 @@
+package payload
+
+import (
+	"encoding/hex"
+	"encoding/json"
+)
+
+type Metadata struct {
+	IV  []byte
+	Key []byte
+}
+
+type jsonMetada struct {
+	IV  string
+	Key string
+}
+
+func (this *Metadata) MarshalJSON() ([]byte, error) {
+	ret := &jsonMetada{
+		IV:  hex.EncodeToString(this.IV),
+		Key: hex.EncodeToString(this.Key),
+	}
+	return json.Marshal(ret)
+}
+
+func (this *Metadata) UnmarshalJSON(data []byte) (err error) {
+	ret := &jsonMetada{}
+	if err = json.Unmarshal(data, ret); err != nil {
+		return err
+	}
+	if this.IV, err = hex.DecodeString(ret.IV); err != nil {
+		return
+	} else if this.Key, err = hex.DecodeString(ret.Key); err != nil {
+		return
+	}
+	return
+}