diff --git a/configure.ac b/configure.ac
index 89c5a83b..b02e7421 100644
--- a/configure.ac
+++ b/configure.ac
@@ -168,6 +168,10 @@ AC_ARG_ENABLE(ssp,
   ])
 ])
 
+AC_ARG_ENABLE(blocking-random,
+[AS_HELP_STRING(--enable-blocking-random,Use /dev/random instead of /dev/urandom)],
+[AC_DEFINE([USE_BLOCKING_RANDOM], [], [Use blocking random])])
+
 AC_ARG_ENABLE(debug,
 [AS_HELP_STRING(--enable-debug,For maintainers only - please do not use)],
 [