Upon HTTP requests, optionally checks user history and/or makes a
HEAD request to detect whether a site supports HTTPS, and if so,
changes the request to use the HTTPS protocol, otherwise keeping
the URL the same (and also optionally deleting the HTTP version
from the history).
Also provides two optional "paranoia modes", one which will replace all
HTTP requests with HTTPS and one which will lead to a blank page
when not found.
IMPORTANT NOTE: Some well-used sites, like Amazon.com
may use the bad practice of mixing http and https for the same domain and redirecting https requests back to http for pages deemed not to be sensitive, thereby potentially compromising at least your privacy. This practice will currently cause my add-on to have a major hiccup when such a site is visited, as my add-on keeps trying to go to the https version, but the site keeps forwarding it back to the http version. I may build in a system to prevent this, such as allowing site-specific exceptions in the future, but as I do not have time at the moment, you may wish to forgo using this add-on until it supports exceptions or disable it when visiting such a site.
For heftier or more nuanced solutions, see: