The presentation software may be closed, the crypto is open. There was even a workshop to build your own. https://www.defcon.org/html/defcon-23/dc-23-workshop

The presentation software may be closed, the crypto is open. There was even a workshop to build your own. https://www.defcon.org/html/defcon-23/dc-23-workshops-schedule.html#Eijah https://www.defcon.org/html/defcon-23/dc-23-workshops-schedu... Most of the posters were obviously not at Defcon based on the comments and general ignorance.