Public Internet cafe's are a common place where email id's get hacked. The most popular technique hackers use is to attach a keylogger to the computer which logs every letter you type. Once you sign out and leave, its a piece of cake to look at what you have typed and figure out your passwords.

Google has a new way to combat this type of hacking - QR code for Google login.

All you need to do is to visit this URL to log into Google - accounts.google.com/sesame. Google will show you a QR code which you can read using your smartphone.

The QR code will open a Google login URL which will prompt you to login to your Google account in your phone. After you are authorised, you will get options to either start with Gmail or iGoogle.

Once you click on a button, Google will automatically authorise you on the PC browser as well and you will be taken to either Gmail or iGoogle as per your choice.You have now logged into your Google account on a browser on the computer using your phone.

The advantage with this technique is that you never have to type your login id or password in a public computer. This will fully protect your Google account from keylogger hacking.

There is a time out period for each QR code session as well. So if you keep your QR code open for a long time without logging in using a phone, the session will time out and Google will show you a timed out error message.

Please keep in mind that using QR code for Google login doesn't mean you don't have to logout. If you leave your session open, it is still accessible to any other person who uses that computer; although you can close your open google sessions from anywhere later on.

UPDATE: For unknown reasons, Google has taken this feature away with a message on the login page -

Hi there - thanks for your interest in our phone-based login experiment.

While we have concluded this particular experiment, we constantly 
experiment with new and more secure authentication mechanisms.

Stay tuned for something even better!

Dirk Balfanz, Google Security Team.