diff --git a/src/NetVar.cc b/src/NetVar.cc
index 248ae15e1a..4a98dc4a25 100644
--- a/src/NetVar.cc
+++ b/src/NetVar.cc
@@ -149,6 +149,11 @@ RecordType* OS_version;
 EnumType* OS_version_inference;
 TableVal* generate_OS_version_event;
 
+OpaqueType* md5_type;
+OpaqueType* sha1_type;
+OpaqueType* sha256_type;
+OpaqueType* entropy_type;
+
 double table_expire_interval;
 double table_expire_delay;
 int table_incremental_step;
@@ -253,6 +258,11 @@ void init_event_handlers()
 
 void init_general_global_var()
 	{
+  md5_type = new OpaqueType("md5");
+  sha1_type = new OpaqueType("sha1");
+  sha256_type = new OpaqueType("sha256");
+  entropy_type = new OpaqueType("entropy");
+
 	table_expire_interval = opt_internal_double("table_expire_interval");
 	table_expire_delay = opt_internal_double("table_expire_delay");
 	table_incremental_step = opt_internal_int("table_incremental_step");
diff --git a/src/NetVar.h b/src/NetVar.h
index 2561fa0ad9..bc0935f1ec 100644
--- a/src/NetVar.h
+++ b/src/NetVar.h
@@ -152,6 +152,12 @@ extern RecordType* OS_version;
 extern EnumType* OS_version_inference;
 extern TableVal* generate_OS_version_event;
 
+class OpaqueType;
+extern OpaqueType* md5_type;
+extern OpaqueType* sha1_type;
+extern OpaqueType* sha256_type;
+extern OpaqueType* entropy_type;
+
 extern double table_expire_interval;
 extern double table_expire_delay;
 extern int table_incremental_step;
diff --git a/src/OpaqueVal.cc b/src/OpaqueVal.cc
index 51f975edf8..23abc91721 100644
--- a/src/OpaqueVal.cc
+++ b/src/OpaqueVal.cc
@@ -1,4 +1,5 @@
 #include "OpaqueVal.h"
+#include "NetVar.h"
 #include "Reporter.h"
 #include "Serializer.h"
 
@@ -72,6 +73,8 @@ bool HashVal::DoUnserialize(UnserialInfo* info)
 	return UNSERIALIZE(&valid);
 	}
 
+MD5Val::MD5Val() : HashVal(md5_type) { }
+
 void MD5Val::digest(val_list& vlist, u_char result[MD5_DIGEST_LENGTH])
 	{
 	MD5_CTX h;
@@ -189,6 +192,8 @@ bool MD5Val::DoUnserialize(UnserialInfo* info)
 	return true;
 	}
 
+SHA1Val::SHA1Val() : HashVal(sha1_type) { }
+
 void SHA1Val::digest(val_list& vlist, u_char result[SHA_DIGEST_LENGTH])
 	{
 	SHA_CTX h;
@@ -297,6 +302,8 @@ bool SHA1Val::DoUnserialize(UnserialInfo* info)
 	return true;
 	}
 
+SHA256Val::SHA256Val() : HashVal(sha256_type)	{ }
+
 void SHA256Val::digest(val_list& vlist, u_char result[SHA256_DIGEST_LENGTH])
 	{
 	SHA256_CTX h;
@@ -410,6 +417,7 @@ bool SHA256Val::DoUnserialize(UnserialInfo* info)
 	return true;
 	}
 
+EntropyVal::EntropyVal() : OpaqueVal(entropy_type) { }
 
 bool EntropyVal::Feed(const void* data, size_t size)
 	{
diff --git a/src/OpaqueVal.h b/src/OpaqueVal.h
index 0428e50bdb..78fa5da5e9 100644
--- a/src/OpaqueVal.h
+++ b/src/OpaqueVal.h
@@ -36,7 +36,7 @@ public:
 			 u_char key[MD5_DIGEST_LENGTH],
 			 u_char result[MD5_DIGEST_LENGTH]);
 
-	MD5Val() : HashVal(new OpaqueType("md5"))	{ }
+	MD5Val();
 
 protected:
 	friend class Val;
@@ -55,7 +55,7 @@ class SHA1Val : public HashVal {
 public:
 	static void digest(val_list& vlist, u_char result[SHA_DIGEST_LENGTH]);
 
-	SHA1Val() : HashVal(new OpaqueType("sha1")) { }
+	SHA1Val();
 
 protected:
 	friend class Val;
@@ -74,7 +74,7 @@ class SHA256Val : public HashVal {
 public:
 	static void digest(val_list& vlist, u_char result[SHA256_DIGEST_LENGTH]);
 
-	SHA256Val() : HashVal(new OpaqueType("sha256"))	{ }
+	SHA256Val();
 
 protected:
 	friend class Val;
@@ -91,7 +91,7 @@ private:
 
 class EntropyVal : public OpaqueVal {
 public:
-	EntropyVal() : OpaqueVal(new OpaqueType("entropy"))	{ }
+	EntropyVal();
 
 	bool Feed(const void* data, size_t size);
 	bool Get(double *r_ent, double *r_chisq, double *r_mean,
diff --git a/src/Val.cc b/src/Val.cc
index 2aafc30ab2..dd86e71a9e 100644
--- a/src/Val.cc
+++ b/src/Val.cc
@@ -3125,13 +3125,12 @@ void VectorVal::ValDescribe(ODesc* d) const
 	d->Add("]");
 	}
 
-OpaqueVal::OpaqueVal(OpaqueType* t) : Val(t), type(t)
+OpaqueVal::OpaqueVal(OpaqueType* t) : Val(t)
 	{
 	}
 
 OpaqueVal::~OpaqueVal()
 	{
-	Unref(type);
 	}
 
 IMPLEMENT_SERIAL(OpaqueVal, SER_OPAQUE_VAL);
diff --git a/src/Val.h b/src/Val.h
index 8544fbadfd..4b2705c5b4 100644
--- a/src/Val.h
+++ b/src/Val.h
@@ -1024,9 +1024,6 @@ protected:
 	OpaqueVal() { }
 
 	DECLARE_SERIAL(OpaqueVal);
-
-private:
-  OpaqueType* type;
 };
 
 // Checks the given value for consistency with the given type.  If an