About 10 years ago when I was working with American Express for a Payment Gateway project, all the internal bank too vendor communications were these encrypted emails with a self-contained HTML file that has the content encrypted inside of them, similar like Portable Secret. Sadly I don't recall the proprietary vendor's name or the name of the technology. Pretty sure I've received similar self-embedded HTML from Chase as well.
IKR? I've been receiving such emails for a long time (and still receiving one every month), and this is not a new idea to me. I really wonder what's inherently different here, because I couldn't find one yet it's being hyped up. The use of crypto API is just an implementation detail that might negatively impact the longevity of a document.
