Portable Secret: End-to-End Encrypted Files in One HTML
blog.alcazarsec.com
blog.alcazarsec.com
(It redirects to https://alcazarsec.com/ps. I just really like short domains)
If there's interest, I can create a new public repo with an open-source license.
I have posted a Show HN with the link to the tool: https://news.ycombinator.com/item?id=47168000
Source code: https://github.com/alcazarsec/portable-secret