Implementing LCDS Security with MDD

[David_Buhler]

I am trying to understand security with MDD.

In my scenario, a user submits a document. I want to ensure that when the document is updated, the person who updated the document is the one who is updating the document.

My concern: If the submittedByUserID is returned to the client, a malicious authenticated user can falsify the headers to change the submittedByUserID.

My initial thoughts: I need to have a userServiceImpl that has a loginUser() method. The loginUser() method sets the user's ID in the session and I need to populate the submittedByUserID with this session information using the update-security-constraint.

1. Am I correct in the approach above? Is there a better way? Am I totally off-base?
   
2. If I am correct, how would I go about implementing this approach?
   

Data Structure:

<model>

    <entity name="User" persistent="true">

        <id name="userID" type="integer" generated="true"/>

        <property name="username" type="string"/>

        <property name="password" type="string"/>

        <property name="documents" type="Document[]"/>

    </entity>

    <entity name="Document" persistent="true">

         <id name="documentID" type="integer" generated="true"/>

        <property name="body" type="blob"/>

         <property name="submittedByUserID" type="integer"/>

    </entity>

</model>