Cloud Computing is the current technology that revolutionize the mobile and IT industry. Most of the mobile vendors are providing extended data storage over the cloud either with the third party cloud service provider such as Samsung Android smart phones with DropBox storage. On the other hand,Apple iPhone and Windows Phone has their own cloud data storage such as iCloud and SkyDrive respectively. However, mobile phone cloud application users are hesitant to move their data from their mobile phone to the cloud service provider because of increasing data security and privacy concern. In this paper, a mobile data security encryption model is proposed to encounter this problem. With the technical advancement in the mobile and cloud computing, an encryption algorithm is designed known as Ghost, Geometric Host for Mobile Data Security.