India, April 22 -- Millions of people are still today using simple password like '123456' and 'qwerty' on critical accounts that could leave them vulnerable, a study by the UK-based National Cyber Security Centre (NCSC) has revealed.

According to the study, people should use combine three random but memorable words together to use as a strong password.

This is the first cyber study from NCSC and the centre analysed public databases of breached accounts to see which words, phrases and strings people use the most.

'123456 topped the list, appearing in over 23 million password strings. 123456789 was the second-most popular string - a number not much harder to crack. Others that were included in the top five are 'qwerty,' 'password' and '1...