HTTPS Extension Adds Default SSL Browsing to Firefox
HTTPS Everywhere encrypts a number of major websites.
The Tor Project and the Electronic Frontier Foundation have released HTTPS Everywhere, a Firefox extension that activates SSL/TSL encryption on sites that support the security setting, but don't feature it as a default when visiting because of partial support, unsecured trackback links or other issues. To alleviate this problem, HTTPS Everywhere writes all requests in HTTPS.
The EFF mentions that HTTPS Everywhere Twitter, Google, Wikipedia, PayPal, The New York Times, and The Washington Post, along with other sites that support the SSL encryption option. It's also possible to write rulesets that define which domains are redirected HTTPS. The EFF offers more information on that here.
To download HTTPS Everywhere, visit eff.org/https-everywhere.