delete sign value

sdk/auth/rpc_signature_composer.go

@@ -85,6 +85,14 @@ func unsignRpcRequest(request *http.Request, signer Signer) (err error) {
 		}
 	}
 
+	if accessKey, err := signer.GetAccessKeyId(); err != nil {
+		return
+	} else if accessKey == "" {
+		return errors.New("access key is not allow empty")
+	} else if accessKey != signParams["access_key"] {
+		return errors.New("illegal access key")
+	}
+
 	signValue, ok := signParams["sign"]
 	if !ok {
 		return errors.New("sign value is not exists")