I have covered this before (here), but, like a bad penny, these arguments keep coming back. The have been cropping up for decades, and the latest rants from Theresa May on regulating the Internet are no different.
So time to bring it up again, and I have updated the video. Please do watch, and maybe show to your MP when you have one.
Update: We are having some work done and my carpenter was around, he saw me working on the video and pulled up a chair to watch it all the way through. That is rare for me as I am a bit techie, but does suggest that even if you are not techie, this is an informative and maybe slightly amusing video - so do watch.
Basically, this explains the very simple method of pen & paper cryptography. Proper school boy stuff. No, I did not invent it, it is old, and simple, and uncrackable, and does not need a computer! It is a simple one-time-pad.
You can't ban it, or stop it, and it shows that the end game of whack-a-mole over controlling terrorist use of encryption is they can still do this, and you can never win. So let's stop playing now and concentrate efforts in other places (some more funding for police may be a good start).