| The defense against that is 'disappearing messages' which is available in most popular E2E messaging apps nowadays, including Signal and WhatsApp.[1] PGP emails doesn't even have forward secrecy. Emails are not messaging, it needs video/voice calls, stickers/gifs etc etc to have any hope of being adopted by non-techy folks. The Signal blog has a number of articles on how they develop state-of-the-art privacy preserving features. [2][3][4][5][6]. Also the only info Signal has about you is "Unix timestamps for when each account was created and the date that each account last connected to the Signal service", which is what it provides to government requests [7]. [1] Disappearing messages https://signal.org/blog/disappearing-by-default/ [2] How to build large-scale end-to-end encrypted group video calls: https://signal.org/blog/how-to-build-encrypted-group-calls/ [3] Signal and GIFs https://signal.org/blog/giphy-experiment/ https://signal.org/blog/signal-and-giphy-update/ [4] Signal groups, https://signal.org/blog/signal-private-group-system/ [5] Sealed sender https://signal.org/blog/sealed-sender/ [6] Private contact discovery https://signal.org/blog/private-contact-discovery/ [7] Government requests https://signal.org/bigbrother/ |
Yeah, that is a bit of a mystery. There is no technical reason. I think that email users just want to keep their old emails around, which of course makes forward secrecy pointless. Perhaps PGP users would prefer to use the greater security available for the private key material in an offline medium like email to make it so they don't get compromised in the first place.