Around 2010, I was using Pidgin to communicate with friends, a universal client to connect to instant messaging platforms. At the time, this would have been MSN, ICQ, AOL messenger, Skype, etc. Even facebook was running its own XMPP server that you could connect to, and communicate with your facebook friends! Pre-enshittification-times were really amazing.
In this pre-Snowden era, end-to-end encryption was pretty much unheard of, TLS was used for βserious stuffβ like online banking. Still, Pidgin had a plugin implementing OTR messaging, which is essentially an ancestor of the Signal protocol. It worked by sending the encrypted messages as plain text messages over any supported service. Me and my friend (who, I believe, was using a different non-Pidgin MacOS client?) would talk to each other using OTR-encrypted messages via Facebook Messenger. Key verification was not a solved issue and had to be done manually using a different channel. And when you opened Facebook itself to look at your messages, all you could see was a bunch of base64(?)-encoded gibberish. Fun times.
The only way to outlaw encryption is to outlaw mathematics. If two (or more) persons want to exchange messages securely, they can and will always be able to do so. If I cannot trust my messaging application, I will find a way that I do not have to trust it, and people that have something to hide even more so. Encryption is not a loophole for criminals; it is a bulwark against tyranny. This proposal will solve no problems, but establish a authoritarian surveillance state.