diff --git a/lmdb-typed.hh b/lmdb-typed.hh
index 366a942..13fde0a 100644
--- a/lmdb-typed.hh
+++ b/lmdb-typed.hh
@@ -80,13 +80,24 @@ inline std::string keyConv(const std::string& t)
 template<>
 inline std::string keyConv(const uint32_t& t)
 {
-  return std::string((char*)&t, sizeof(4));
+  return std::string((char*)&t, sizeof(t));
 }
 template<>
 inline std::string keyConv(const int32_t& t)
 {
-  return std::string((char*)&t, sizeof(4));
+  return std::string((char*)&t, sizeof(t));
 }
+template<>
+inline std::string keyConv(const uint64_t& t)
+{
+  return std::string((char*)&t, sizeof(t));
+}
+template<>
+inline std::string keyConv(const int64_t& t)
+{
+  return std::string((char*)&t, sizeof(t));
+}
+
 
 
 /** This is a struct that implements index operations, but 
diff --git a/typed-test.cc b/typed-test.cc
index 49bbc13..3517500 100644
--- a/typed-test.cc
+++ b/typed-test.cc
@@ -1,5 +1,5 @@
 #include <iostream>
-
+#include <time.h>
 #include "catch2/catch.hpp"
 #include "lmdb-typed.hh"
 
@@ -9,21 +9,22 @@ struct Member
 {
   std::string firstName;
   std::string lastName;
+  time_t enrolled;
 };
 
 template<class Archive>
 void serialize(Archive & ar, Member& g, const unsigned int version)
 {
-  ar & g.firstName & g.lastName;
+  ar & g.firstName & g.lastName & g.enrolled;
 }
 
-
-
 TEST_CASE("Basic typed tests", "[basictyped]") {
   unlink("./tests-typed");
   typedef TypedDBI<Member,
-           index_on<Member, string, &Member::firstName>,
-           index_on<Member, string, &Member::lastName> > tmembers_t;
+                   index_on<Member, string, &Member::firstName>,
+                   index_on<Member, string, &Member::lastName>,
+                   index_on<Member, time_t, &Member::enrolled>
+                   > tmembers_t;
 
   auto tmembers = tmembers_t(getMDBEnv("./tests-typed", MDB_CREATE | MDB_NOSUBDIR, 0600), "members");
   
@@ -34,6 +35,7 @@ TEST_CASE("Basic typed tests", "[basictyped]") {
   txn.put(m);
   m.firstName="bertus";
   m.lastName = "testperson";
+  m.enrolled = time(0);
   txn.put(m);
 
   m.firstName = "other";