پرداخت موبایلی استوار به صورت ناشناس در برابر ارائه دهنده ی خدمات شخص ثالث نادر Strong anonymous mobile payment against curious third‑party provider

1 Introduction As mobile terminals are widespread, m-commerce comes into the people’s lives. It breaks the constraints of time and space and allows people to make transactions anywhere and anytime [1]. It brings great conveniences to consumers. Payment plays an important role in m-commerce and current prevailing payment systems are based on a third-party payment provider (TPP). As an intermediary between merchants and customers, TPP integrates multiple payment ways with diferent bank cards into a unifed interface and makes m-commerce more convenient and faster. PayPal has a TPP and it is used by many users around the world. Paypal does not provide anonymity and it can obtain more details other than the order and the receiving merchant. Preibusch et al. [2] analyzed the 881 most popular US web shops and found that more than half of the sites shared with PayPal customers’ details including their names, emails, postal addresses and their bank accounts. Also, sites sell PayPal sensitive product details such as adult toys and medication. And even worse, PayPal forwards shopping details of customers to Omniture, a third party data aggregator with even larger tracking reach than PayPal. In China, Alipay is a prevailing payment tool. As a TPP, it also provides the guarantee service of transactions on Taobao website, which is the largest e-commerce platform in China. Alipay can monitor consumption choices, obtain product name, buyer’s delivery address, and purchase time. Further, it can build up a fne-grained and comprehensive consumption profle. In addition, the payment using PayPal or Taobao usually links to a credit card number or a bank account, which serves as a persistent identifer. Using the persistent identifer, PayPal or Taobao can link multiple transactions of diferent shopping websites to one buyer. So, it is a more serious privacy leaks issue than browsing web. Another diferent type is Bitcoin, which was created in a 2008 academic paper by a still unknown person using the name Satoshi Nakamoto [3]. It is a cryptographically secure decentralized peer-to-peer electronic payment system. It provides anonymity but does not use a TPP. The trust in Bitcoin is implemented by a public digital ledger called blockchain. This ledger keeps records for all coin transactions, which is obtained by all Bitcoin network nodes. The job of keeping the system running is left to a volunteer workforce known as Bitcoin miners. The calculations are so intense that computers used for calculations emit the heat keeping the room at a high temperature. Therefore, high energy consumption becomes a main weakness of Bitcoin.