diff --git a/src/net/java/sip/communicator/service/protocol/OperationSetInstantMessageTransform.java b/src/net/java/sip/communicator/service/protocol/OperationSetInstantMessageTransform.java
new file mode 100644
index 000000000..2ab9c1a20
--- /dev/null
+++ b/src/net/java/sip/communicator/service/protocol/OperationSetInstantMessageTransform.java
@@ -0,0 +1,66 @@
+/*
+ * SIP Communicator, the OpenSource Java VoIP and Instant Messaging client.
+ *
+ * Distributable under LGPL license.
+ * See terms of license at gnu.org.
+ */
+package net.java.sip.communicator.service.protocol;
+
+/**
+ * The Instant Message Transform operation set allows, when \
+ * supported to insert message transform layers that could change incoming
+ * messages before they are delivered to the user and outgoing ones before
+ * they reach the protocol stack and get sent. One use case of this operation
+ * set is support of upper layer encryption mechanisms like OTR. Other cases may
+ * include hyperlink presentation, support for wiki words etc.
+ * <p/>
+ * Important Notice: As of May 5 2009, this operation set is still a work in
+ * progress and may change significantly in the following months. Any work based
+ * on this interface is therefore likely to require frequent updates to keep
+ * compatibility.
+ *
+ * @author Emil Ivov
+ *
+ */
+public interface OperationSetInstantMessageTransform
+{
+    /**
+     * Adds a transformation layer to this protocol provider using a default
+     * priority value.
+     *
+     * @param transformLayer the <tt>TransformLayer</tt> that we'd like to add
+     * to our protocol provider.
+     */
+    public void addTransformLayer(TransformLayer transformLayer);
+
+    /**
+     * Adds <tt>transformLayer</tt> to the layers currrently used for message
+     * transformation in this provider and assigns the specified
+     * <tt>priotity</tt> to it.
+     *
+     * @param priority the priority/order index that we'd like to insert
+     * <tt>transportLayer</tt> at.
+     * @param transformLayer the layer we are registering
+     */
+    public void addTransformLayer(int priority, TransformLayer transformLayer);
+
+    /**
+     * Removes <tt>transformLayer</tt> from the list of currently registered
+     * transform layers so that it won't be notified for further message events.
+     *
+     * @param transformLayer the layer we are trying to remove.
+     */
+    public void removeTransformLayer(TransformLayer transformLayer);
+
+    /**
+     * Determines whether <tt>layer</tt> is currently registered with this
+     * provider.
+     *
+     * @param layer the layer for which we'd like to know whether it is
+     * currently registered with this provider.
+     *
+     * @return <tt>true</tt> if <tt>layer</tt> is currently registered with this
+     * provider and <tt>false</tt> otherwise.
+     */
+    public boolean containsLayer(TransformLayer layer);
+}
diff --git a/src/net/java/sip/communicator/service/protocol/TransformLayer.java b/src/net/java/sip/communicator/service/protocol/TransformLayer.java
new file mode 100644
index 000000000..683bc41ed
--- /dev/null
+++ b/src/net/java/sip/communicator/service/protocol/TransformLayer.java
@@ -0,0 +1,93 @@
+/*
+ * SIP Communicator, the OpenSource Java VoIP and Instant Messaging client.
+ *
+ * Distributable under LGPL license.
+ * See terms of license at gnu.org.
+ */
+package net.java.sip.communicator.service.protocol;
+
+import net.java.sip.communicator.service.protocol.event.*;
+
+/**
+ * An instance of the <tt>TransformLayer</tt>, when registered with
+ * <tt>OperationSetInstantMessageTransform</tt> would be passed all message
+ * events. The class looks a lot like a <tt>MessageListener</tt> with the major
+ * difference being that all the methods are defined with a return value. The
+ * events we return would contain all message details after their transformation
+ * from by the layer implementation. All methods return <tt>null</tt> in case
+ * the <tt>TransformLayer</tt> implementation determines that the message event
+ * should not be determined to the upper layers.
+ * <p/>
+ * Important Notice: As of May 5 2009, this operation set is still a work in
+ * progress and may change significantly in the following months. Any work based
+ * on this interface is therefore likely to require frequent updates to keep
+ * compatibility.
+ *
+ * @author Emil Ivov
+ *
+ */
+public interface TransformLayer
+{
+    /**
+     * Called when a new incoming <tt>Message</tt> has been received. The method
+     * returns an instance of <tt>MessageReceivedEvent</tt> which in many cases
+     * would be different from the <tt>evt</tt> instance that was passed as
+     * param. The param and the return instances could very well (and will
+     * often) be instances of different implementations so users of this
+     * interface (i.e. protocol implementors) should make no assumptions
+     * for the class of the return type and copy the returned instance into
+     * a new one if necessary.
+     *
+     * @param evt the <tt>MessageReceivedEvent</tt> containing the newly
+     * received message, its sender and other details.
+     *
+     * @return an instance of a (possibly new) <tt>MessageReceivedEvent</tt>
+     * instance containing the transformed message or <tt>null</tt> if the
+     * <tt>TransportLayer</tt> has determined that this message event should not
+     * be delivered to the upper layers.
+     */
+    public MessageReceivedEvent messageReceived(MessageReceivedEvent evt);
+
+    /**
+     * Called when the underlying implementation has received an indication
+     * that a message, sent earlier has been successfully received by the
+     * destination. The method returns an instance of
+     * <tt>MessageDeliveredEvent</tt> which in many cases would be different
+     * from the <tt>evt</tt> instance that was passed as a parameter. The param
+     * and the return instances could very well (and will often) be instances of
+     * different implementations so users of this interface (i.e. protocol
+     * implementors) should make no assumptions for the class of the return type
+     * and copy the returned instance into a new one if necessary.
+     *
+     * @param evt the MessageDeliveredEvent containing the id of the message
+     * that has caused the event.
+     *
+     * @return an instance of a (possibly new) <tt>MessageDeliveredEvent</tt>
+     * instance containing the transformed message or <tt>null</tt> if the
+     * <tt>TransportLayer</tt> has determined that this message event should not
+     * be delivered to the upper layers.
+     */
+    public MessageDeliveredEvent messageDelivered(MessageDeliveredEvent evt);
+
+    /**
+     * Called to indicated that delivery of a message sent earlier has failed.
+     * Reason code and phrase are contained by the <tt>MessageFailedEvent</tt>
+     * The method returns an instance of
+     * <tt>MessageDeliveredEvent</tt> which in many cases would be different
+     * from the <tt>evt</tt> instance that was passed as a parameter. The param
+     * and the return instances could very well (and will often) be instances of
+     * different implementations so users of this interface (i.e. protocol
+     * implementors) should make no assumptions for the class of the return type
+     * and copy the returned instance into a new one if necessary.
+     *
+     * @param evt the <tt>MessageFailedEvent</tt> containing the ID of the
+     * message whose delivery has failed.
+     *
+     * @return an instance of a (possibly new) <tt>MessageDeliveredEvent</tt>
+     * instance containing the transformed message or <tt>null</tt> if the
+     * <tt>TransportLayer</tt> has determined that this message event should not
+     * be delivered to the upper layers.
+     */
+    public MessageDeliveryFailedEvent
+                        messageDeliveryFailed(MessageDeliveryFailedEvent evt);
+}