The new extension will allow users to encrypt the information they share on social networking platforms like Facebook and Twitter.
The HTTPS Everywhere add-on works with websites including Google Search, Wikipedia, Identi.ca, Ixquick, DuckDuckGo, Scroogle and some search engines.
The outfits said that the HTTPS Everywhere Firefox add-on has been inspired by the encrypted search option launched by the search giant Google.
EFF explained that many websites offered support for HTTPS, but made it very difficult to use.
The organisation warns that if the bottom bar on the Firefox browser window displays an exclamation mark or a broken lock icon, it means that the users may be vulnerable to eavesdropping or hacking attacks.
The add-on improves security, but will not be able to provide complete protection as many websites contain insecure third-party content.