Invisible wall that masks from one side?

Hello, I am working on an AR project. What I am working for is to get an effect of depth inside the paper I printed the QR code on. So what I need is a cube that you can see the inside, but from the outside it cannot be seen and masks the interior. Same effect can be seen here;

So I need a wall shader that can do this. I am very ameteur at shaders in Unity. Thanks in advance.

Hello, shaders is a way of doing this but not needed, but the easiest approach is to create a square using 6 quads, but rather than make the quuads look to us rotate them 180 degress, not sure if i have been clear enough.

You can hide geometry by writing to the z-buffer (i.e. pretending that there is something blocking the view) without actually drawing anything. Try this shader on a box that’s open on one side.

Shader "Unlit/Mask" {
	SubShader {
		Tags { "RenderType"="Opaque" "Queue"="Geometry-100" }
		LOD 100

		Pass {
			ColorMask 0
		}
	}
}