diff --git a/src/oidcmsg/constant.py b/src/oidcmsg/constant.py
new file mode 100644
index 0000000..cbf2333
--- /dev/null
+++ b/src/oidcmsg/constant.py
@@ -0,0 +1 @@
+MAXIMUM_CLOCK_SKEW = 300
\ No newline at end of file