As the survey shows that smartphone penetration rate in Korea is 91% by 2016 and smartphone penetration rate in 70% of the world's 50 countries, smartphones are becoming a necessity. In addition, hacking into mobile devices is increasing rapidly with the increase of mobile device users. As the market share of Android OS increases, hacking of mobile devices has focused on Android devices. Although there are many security solutions for mobile devices, they are fragmentary for mobile threats; that is, they are solutions for only several threats rather than comprehensive solutions. There is hence a limit to protecting user's and company's data stored or used on mobile devices from various types of hacking. To address this, we propose a mobile device protection technology based on domain isolation. We believe this is a fundamental solution for protecting the mobile device users from hacking. We implemented and tested various mobile applications operating on a mobile device that incorporates our proposed structure based on domain isolation. Virtualization technology has emerged to increase CPU utilization in server-class PCs and to run various OSs in one system. As these virtualization technologies become lightweight, they are beginning to be applied to embedded devices. In this paper, we applied this lightweight embedded virtualization technology to mobile devices to divide mobile devices into two areas. Therefore, users can have hidden area from hacker attack in addition to Android OS area which can use same as existing mobile device. There is a hardware-based mobile security solution using a secure element(SE), but this has to be reflected in the manufacturing process of the mobile device. However, since the domain separation technology using the virtualization, proposed in this paper, is a software solution, it has an advantage that it can be applied to a device that is already in use. In addition, to protect the hidden area, application authentication/authorization and user authentication technology were applied. And we use white-box cryptography to get root-of-trust of the key which is used for secure storage and data encryption/decryption. We believe this is a fundamental solution for protecting the mobile device users from hacking. We implemented and tested various mobile applications operating on a mobile device that incorporates our proposed structure based on domain isolation. There is some performance degradation caused by the domain separation, but it is negligible.