Due to the prosperity of ubiquitous computing and mobile communication technologies, the traditional commerce will start changing drastically. A shopping model has shown how the customers make a purchase from before-shopping to post-shopping through a ubiquitous device. However, the ubiquitous computing system gathers the sensitive personal information such as location and credit card information. Therefore, security and privacy have become important issues which should be taken into account in the system. In order to solve these problems, this paper tries to design a helpful and secure ubiquitous shopping protocol which is combined with the shopping model to make it practical, secure, and convenient. Due to the prosperity of ubiquitous computing and mobile communication technologies, the traditional commerce will start changing drastically. A shopping model has shown how the customers make a purchase from before-shopping to post-shopping through a ubiquitous device. However, the ubiquitous computing system ginse the sensitive personal information such as location and credit card information. Therefore, in order to solve these problems, this paper tries to design a helpful and secure ubiquitous shopping protocol which is combined with the shopping model to make it practical, secure, and convenient.