diff --git a/build.xml b/build.xml
index 73c3385e..7c824d6e 100644
--- a/build.xml
+++ b/build.xml
@@ -597,6 +597,10 @@
 			<arg line="pack /d appx /p ${title}_${version}.appx" />
 		</exec>
 
+		<exec executable="signtool" dir="${dir.dist}" failonerror="yes">
+			<arg line="sign /fd SHA256 /t http://time.certum.pl/ /v /a ${title}_${version}.appx" />
+		</exec>
+
 		<copy todir="${dir.release}" file="${dir.dist}/${title}_${version}.appx" verbose="yes" />
 	</target>