diff --git a/src/main/java/com/threerings/presents/net/PublicKeyCredentials.java b/src/main/java/com/threerings/presents/net/PublicKeyCredentials.java
index 131f66d77..76d3ace4d 100644
--- a/src/main/java/com/threerings/presents/net/PublicKeyCredentials.java
+++ b/src/main/java/com/threerings/presents/net/PublicKeyCredentials.java
@@ -48,6 +48,15 @@ public class PublicKeyCredentials extends Credentials
         _secret = SecureUtil.createRandomKey(16);
         _salt = SecureUtil.createRandomKey(4);
         _encodedSecret = SecureUtil.encryptBytes(key, _secret, _salt);
+        _secureVersion = SecureUtil.VERSION;
+    }
+
+    /**
+     * Returns the secure version the client is using.
+     */
+    public int getSecureVersion ()
+    {
+        return _secureVersion;
     }
 
     /**
@@ -81,6 +90,9 @@ public class PublicKeyCredentials extends Credentials
     /** Our verification salt. */
     protected byte[] _salt;
 
+    /** Our secure version. */
+    protected int _secureVersion;
+
     /** Our secret key. */
     protected transient byte[] _secret;
 }
diff --git a/src/main/java/com/threerings/presents/server/net/AuthingConnection.java b/src/main/java/com/threerings/presents/server/net/AuthingConnection.java
index 90d877406..394eb9367 100644
--- a/src/main/java/com/threerings/presents/server/net/AuthingConnection.java
+++ b/src/main/java/com/threerings/presents/server/net/AuthingConnection.java
@@ -63,8 +63,10 @@ public class AuthingConnection extends PresentsConnection
                         } else {
                             // generate a server key and encode it using the client key
                             SecureResponse resp = new SecureResponse();
-                            _serverSecret = resp.createSecret(
-                                (PublicKeyCredentials)secreq.getCredentials(), key, 16);
+                            PublicKeyCredentials pkcreds =
+                                    (PublicKeyCredentials)secreq.getCredentials();
+                            _clientSecureVersion = pkcreds.getSecureVersion();
+                            _serverSecret = resp.createSecret(pkcreds, key, 16);
                             safePostMessage(resp);
                         }
                         return;
@@ -176,5 +178,10 @@ public class AuthingConnection extends PresentsConnection
     protected AuthRequest _authreq;
     protected AuthResponse _authrsp;
     protected Name _authname;
+
+    /** The random secret generating for this connection. */
     protected byte[] _serverSecret;
+
+    /** The secure version for our connecting client. */
+    protected int _clientSecureVersion;
 }
diff --git a/src/main/java/com/threerings/presents/util/SecureUtil.java b/src/main/java/com/threerings/presents/util/SecureUtil.java
index 684de930b..28f0d7e74 100644
--- a/src/main/java/com/threerings/presents/util/SecureUtil.java
+++ b/src/main/java/com/threerings/presents/util/SecureUtil.java
@@ -45,6 +45,9 @@ import static com.threerings.presents.Log.log;
  */
 public class SecureUtil
 {
+    /** The version of our security protocol (for backwards compatability with older clients). */
+    public static final int VERSION = 1;
+
     /**
      * Creates our AES cipher.
      */