The Secret Tartan

This note is my first introduction to the tartan. Now it seems awkward and less general than it should be. The motivating scenario does not suggest the power. I think the tartan addresses the problems described here. Marc Stiegler brought forth this idea and named it. There are useful variations that should be noted before they are patented.

The tartan is a pattern for the screen known by an object, named “TM” here, in the system with the authority to write on the screen. The tartan is shaped as a picture frame. The tartan was created when the computer was new in a session where the principle user may interact with the system to choose the tartan. The tartan is thus known to only TM and the principle user.

There are a few objects in the system with a facet capability for TM to send TM a text message. TM knows the message source and draws the tartan with the name of the source and the message. The message may include a mark indicating to TM to include a text entry box for a text response to the originating object.

Such schemes have appeared for decades in military security systems with less attention to the user perspective, perhaps. The military refers to it as a secure user channel.

Input and Output

This path goes both ways. When some programs (with the right TM facet) ask for a password the user will reveal the PW with assurance that it is going to the program with legitimate need. When some program (with the right TM facet) asks the user to insert a USB drive, the user can do so without risking doom.


Some messages via TM will be so rare that use user does not recognize the source, or does not even recognize the tartan. This note suggests some costs to the tartan but does not consider them further here.

This plan presumes that even read access to the screen is closely limited.

Reading the screen, either from inside or outside, must be made difficult.


A new led about the size of the one that announces that the camera is active would serve.

User Initiative

A keyboard pattern, or an extra key could allow the user to signal TM or similar object, to initiate a conversation bypassing the authority of the program which normally has ultimate screen access. Some military systems used this pattern for when a new user logged into the system.