--- XTEA.orig.pm	2016-02-17 04:53:07.000000000 +0100
+++ XTEA.pm	2016-03-04 10:19:52.374916400 +0100
@@ -23,10 +23,10 @@
 my $ELEMENTS_IN_BLOCK = $BLOCK_SIZE / 4;
 
 
-use constant keysize => $KEY_SIZE;
+sub keysize { $KEY_SIZE }
 
 
-use constant blocksize => $BLOCK_SIZE;
+sub blocksize { $BLOCK_SIZE }
 
 
 sub new {