diff --git a/ext/digest/extconf.rb b/ext/digest/extconf.rb
index 4219c0a..b5abbfa 100644
--- a/ext/digest/extconf.rb
+++ b/ext/digest/extconf.rb
@@ -1,2 +1,3 @@
 require 'mkmf'
+$CFLAGS << " -fvisibility=hidden"
 create_makefile('digest/sha3')
diff --git a/ext/digest/sha3.c b/ext/digest/sha3.c
index 9372a3a..92965da 100644
--- a/ext/digest/sha3.c
+++ b/ext/digest/sha3.c
@@ -119,7 +119,7 @@ rb_sha3_singleton_digest(int argc, VALUE *argv, VALUE klass) {
 	}
 }
 
-void
+void __attribute__((visibility("default")))
 Init_sha3() {
 	mDigest = rb_define_module("Digest");
 	cSHA3 = rb_define_class_under(mDigest, "SHA3", rb_cObject);