" Closing a letter—a physical object without even a ghost in the cloud, all that data on one frail piece of paper—with an even more malleable substance, bearing, of all things, an ideographic signature! Informing any handler of the message’s sender, her role, perhaps even her purpose! Madness—from an operational-security perspective. But, "

― Amal El-Mohtar , This Is How You Lose the Time War