The use of untrusted computers to access critical information introduces one of the main challenges in protecting the security of users' confidential information. Providing an easy method of accessing such information, without releasing long term credentials and by trusting on less vulnerable devices, is one of the main research areas being investigated by researchers all around the world. Cell phones with their growing functionalities and inherent personalized nature are attracting a lot of attention to be used as tokens to authenticate users. However, their screen size and small keypads makes it impossible to use them for long term transactions. We introduce a two-factor authentication method that not only benefits from the personalized features of cell phones but also allows users to simply use the untrusted client without any fear of losing critical information.