A method, system, and medium are provided for operating a computing device and a mobile device to access computer software with a secure access and to access a packet network, and for operating a computer software on a mobile device with different computing devices. A mobile device is used to authenticate a user's access to computer software. The computer software may reside on the mobile device, the user's computing device, or another computing device. A unique identifier is stored in the mobile device associated with the computer software to enable the authentication.