Passwordless Login System for Mobile Phones Using CAPTCHA

In last 20 years, the Internet and mobile communication growth in parallel. There are many sites specially designed for mobile phones that users must enter username and password to enter them. In this paper we introduce a new method based on CAPTCHA which does not require entering any password. Instead of entering the password, an image of a number is shown to the user and he/she must type it. The user response is coded with his/her mobile phone IMEI and sent to the server. The server checks user's response according to user's IMEI and if it was correct, let the user to enter the site, so there is no need to enter any password. This method has been implemented in PHP and J2ME languages and tested with a Nokia N71 phone.