While Praxen and those few never perfected an optical cloak, they discovered, by speed of thought, that an idea cluster was generally sufficient to hide secrets in plain sight. As Regent Ellsworth himself was fond of being quoted, "The adult mind — it knows many things. Alas, curiosity is not one of them."
By layering ideas, manifested as handwriting upon sheets of Uli-paper, wrapped into tight scarves as a ball of twine (like a familiar roadside attraction) might be, said target would be accessible to the knowing, yet a blind spot to the know-not.
Even warriors of the Kreln, cliched in their furrowed brows and surly disposition, used these techniques to great advantage: passing out battle-plans on the open fields, even before the eyes of the enemy. And it was perhaps with little time that idea clusters proved ingenious: by thrust of sheer mental momentum, attacks could be coordinated and executed within few minutes, without the need for strong computerate encryption, without the need for a different language. But then again, this was a tongue unto its own, wasn't it?
Often, all that was needed to open the idea cluster up… was an askxe.