diff --git a/configure.ac b/configure.ac
index 205cffd..4bcfd0f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -12,6 +12,7 @@
 AC_LANG([C++])
 
 AX_CXX_COMPILE_STDCXX_11(, optional)
+AX_CHECK_OPENSSL
 
 AC_MSG_CHECKING([for std::shared_ptr])
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM(