The 'Always use HTTPS' option means, once users log in, all Twitter interaction is encrypted automatically.
Paul Ducklin, head of technology at Sophos, said: "If you don't use HTTPS, imposters who listen in to your Twitter traffic can obtain what's called your session key - a secret code which identifies you for as long as you're logged in. This means that they can impersonate you, posting any old tweets on behalf of you or your company."
"Every time you use unencrypted WiFi, for example in a coffee shop or an airport lounge, any one of the other users sitting round could hijack your Twitter session. If you're a Twitter user, it's a no-brainer, you want this new option. Turn it on today," he advised.
Twitter said in a blog post it hopes to make HTTPS a default setting in the future.
Some settings do not force HTTPS, such as when accessing Twitter from mobile browser where users should go to https://mobile.twitter.com. Twitter advises users to check if third-party applications offer HTTPS.
To turn on the HTTPS option:
- Go to 'Settings' on Twitter profile
- Tick the box next to 'Always use HTTPS'
- Save changes
This story was first published by Computer Weekly