But communication by an anonymous sender, and, indeed, anonymous sending of small physical objects, has been available ever since public postal services were im

But communication by an anonymous sender, and, indeed, anonymous sending of small physical objects, has been available ever since public postal services were implemented, in the 17th century. I'm not sure it's worth trying to roll that back. Real-time full-duplex encrypted and off-the-record communication between several anonymous parties is a new thing that skilled people can, with difficulty, obtain today.