I don't have g00gle play store installed, so I am getting this error when I try to create password and note:
Yes, I have added alerts to handle the case when Google Play services are either not installed, or Play Integrity returns an error. Even if you install Play Services in the emulator, it won't pass the further checks, since Play Services verifies whether you have a real device (this is called Play Integrity API).
However, I still think you need to have usable option for desktop users...
I found a product that works on the Desktop, and which is similar to Crosspass in concept. It is called Magic Wormhole, and it was created in 2006.
https://github.com/magic-wormhole/magic-wormholeThe fact that it is not widely used is saying something, namely that it is too technical and too real-time.
I also began planning to add a feature to send images, not just text. This is useful if you need to send someone your driving license or a passport photo.
What's the difference from sending image with encrypted email or other encrypted chatting app?
This is a summary of advantages of Crosspass stated earlier, and they apply to images as much as text. The difference is that Crosspass enforces key verification as part of the natural flow, via the PIN which looks just like an OTP familiar to users. All other services rely on public keys being managed by an untrusted party (a server). This allows the third party to MITM you at will. The other issue is JavaScript backdoors which become a problem with webmail (ProtonMail), or anything inside the web browser.
Furthermore, if you are sending a Driving Licence or a Passport, most likely the recipient is some clerk in some company. He will not jump through hoops to receive your encrypted image. He will not signup with ProtonMail. And he will not give you his private phone number for Signal or WhatsApp.