diff --git a/mask_expected_results.sh b/mask_expected_results.sh
new file mode 100755
index 0000000..f679194
--- /dev/null
+++ b/mask_expected_results.sh
@@ -0,0 +1,7 @@
+#!/bin/sh
+# to prevent diffs due to timing and source file lines, mask some numbers
+
+for target in */expected-results.xml; do
+  sed -i "s/time='[^']*'/time='MASKED'/g" "$target"
+  sed -i 's/ttcn:[0-9]\+/ttcn:MASKED/g' "$target"
+done