This has been my spare time project for a while now. Any feedback would be much appreciated! Here's the overview link:
https://digitsend.com/product-tour
My problem with the existing solutions is that if I need to send sensitive data to somebody, I generally have to set up an account for them and communicate a temporary password. Because sending the temporary password over email defeats the purpose, I wind up calling them and the whole process takes longer than it should.
With this, the sender just types the email and enters the receiver's phone number. A link is emailed to the receiver. When the receiver goes to read it, the website calls them. Once verified, the receiver can choose a password and log in sans-phone in the future.
So it's basically send-and-forget for the sender, and a two-factor, one-time registration process for the receiver.