لب‌خواني: روش جديد احراز هويت در برنامه‌هاي كاربردي گوشي‌هاي تلفن همراه اندرويد

Lip Reading: a New Authentication Method in Android Mobile Phone’s Applications

در اين مقاله با استفاده از پردازش اطلاعات تصويري لب‌هاي كاربر، كلمه عبور با استفاده از دوربين گوشي دريافت مي‌شود تا با استفاده از الگوريتم‌هاي لب‌خواني، حركات لب دنبال شده و تشخيص داده شود. تشخيص تصويري كلمه عبور، مانع از دزديدن آن توسط نرم‌افزارهاي واقعه‌نگار مي‌شود. با اين حال، سيار‌بودن گوشي همراه منجر به تغيير نور محيط مي‌شود. در اين پژوهش، روشي براي حل اين چالش مطرح شده و در‌نهايت يك نمونه برنامه كاربردي براي اجرا در سيستم عامل اندرويد طراحي و پياده‌سازي شده است. اين لب‌خوان به‌صورت غير‌بر‌خط و بدون نياز به ارتباطات اينترنتي و وجود يك سرور خارجي، عمل شناسايي كلمه عبور كاربر را انجام مي‌دهد. موفقيت روش پياده‌سازي‌شده در تشخيص،حدود 70 درصد است. اين برنامه براي پردازش ويديوي حرفي كه 10 قاب دارد، به 3.8 ثانيه زمان و 628 كيلوبايت حافظه نياز دارد كه به‌راحتي در گوشي‌هاي تلفن همراه امروزي قابل دسترس است.

Today, mobile phones are one of the first instruments every individual person interacts with. There are lots of mobile applications used by people to achieve their goals. One of the most-used applications is mobile banks. Security in m-bank applications is very important, therefore modern methods of authentication is required. Most of m-bank applications use text passwords which can be stolen by key-loggers. Key-loggers are hidden software to record the keys struck by users. To overcome the key-logging issue, One-Time Passwords are used. They are secure but require additional tools to be used, therefore they cannot be user-friend. Moreover, the voice-based passwords are not secure enough, since they can be heard by other people easily. In other hand, Image-based passwords cannot satisfy users, cause of screen limitation in mobile phones. In this article, a new authentication method is introduced. The password is based on user lip’s motion which is received via a mobile cellphone camera. The visual information extracted from the user’s lips movement forms the password. Then the lip motion is tracked to recognize the password by incorporating the lip reading algorithms. The algorithm is based on the Viola-Jones method. It combines the method with a pixel-based approach to segment lips and extract features. After segmenting the lips, some special points of Region of Interests are selected. The information extracted from lips are saved in order to act as algorithm’s features. In addition, some normalizing methods are considered to normalize the features and prepare them to enter classification phase. In classification step, some known algorithms like Support Vector Machine and K-Nearest Neighbor are applied on features to recognize password and authenticate people. Visual passwords prevent key-loggers from stealing passwords. However, the mobility of a mobile user causes ambient lights to vary in different environments. In this research, a solution is designed to tackle this challenge. Finally a mobile banking application is designed and developed to run on android mobile phones platform. It incorporates a lip reader which recognizes the passwords in offline mode. The application is independent from the internet connection or a dedicated server. The implemented recognition method has achieved a 70% success rate. In this application a video capture of a letter with 10 frames could be processed in 3.8 seconds using 628 kilo bytes of memory. These resources are easily available in today’s mobile phones. Some mobile bank users tested the application to feedback about lip reading password. Most of them were satisfied when using it. They believed the lip reader is more trustable than text passwords and voice-based passwords. In addition, the user-friendliness of it, is a bit more than text password which means that the method can satisfies a mobile bank application user.