Electric motor bike charge application: assume the charge is free for each session of 20 minutes charge, if user chooses to watch a one-minute advertisement on the mobile phone. Otherwise the user will have to pay a fee for the charge. Please design a secure blockchain ledger system for charge station owners, users, and advertisers. The system can record the charge usage, ads views, and the token reward program such that the token reward is based on the charge station usage. Design your process such that the reward program data is secure for all parties and cannot be colluded to fake usage (to earn reward tokens) or fake viewing advertisement (to earn free charge).