diff --git a/GC/ShareSecret.h b/GC/ShareSecret.h
index 1a7f8be3..a7c32e85 100644
--- a/GC/ShareSecret.h
+++ b/GC/ShareSecret.h
@@ -124,6 +124,8 @@ public:
     {
     }
 
+    static void read_or_generate_mac_key(string, const Names&, mac_key_type) {}
+
     static ReplicatedSecret constant(const clear& value, int my_num, mac_key_type)
     {
       ReplicatedSecret res;
diff --git a/Processor/Machine.hpp b/Processor/Machine.hpp
index 90212825..11c4b5c6 100644
--- a/Processor/Machine.hpp
+++ b/Processor/Machine.hpp
@@ -37,6 +37,7 @@ Machine<sint, sgf2n>::Machine(int my_number, Names& playerNames,
   // Set up the fields
   sgf2n::clear::init_field(lg2);
   sint::clear::read_or_generate_setup(prep_dir_prefix<sint>(), opts);
+  sint::bit_type::mac_key_type::init_field();
 
   // make directory for outputs if necessary
   mkdir_p(PREP_DIR);
@@ -50,6 +51,8 @@ Machine<sint, sgf2n>::Machine(int my_number, Names& playerNames,
 
   sint::read_or_generate_mac_key(prep_dir_prefix<sint>(), N, alphapi);
   sgf2n::read_or_generate_mac_key(prep_dir_prefix<sgf2n>(), N, alpha2i);
+  sint::bit_type::part_type::read_or_generate_mac_key(
+      prep_dir_prefix<typename sint::bit_type>(), N, alphabi);
 
 #ifdef DEBUG_MAC
   cerr << "MAC Key p = " << alphapi << endl;