I run a E2E system using public and private keys. It's really not that complex.
Sure, it's not free, but the implementation effort was 1/100 of the UI work.
Clients encrypt data in the browser, share id of the data and key (+ optional password). Some other clients receive id of the data and the key and read it.
For a notification service, you would just need a setup step to generate a key and store it in the browser + on the phone.
That said, I'm not sure I understand why would someone need to notify its own phone.
Clients encrypt data in the browser, share id of the data and key (+ optional password). Some other clients receive id of the data and the key and read it.
For a notification service, you would just need a setup step to generate a key and store it in the browser + on the phone. That said, I'm not sure I understand why would someone need to notify its own phone.