Mobile devices are gaining more and more features and thus they are becoming more valuable to their users with the amount of important information they possess. However, mobile devices are not the same as computers, and the idea is to make sure users still find their phones easy to use, reliable, secure, and trustworthy. For this purpose, the Symbian platform security model is introduced. The purpose of the model is not to close the phones but to enable users to continue using their mobile phones as before in an easy and trusted manner. This way it is possible to provide more intelligent devices to a larger user base and this will offer a larger audience for applications.