As a group, we recognized the problem of fake reviews and did more in depth research in the issue. We found out that more and more sketchy companies are turning to fake reviews to inflate the apparent quality of their products. Companies are using bots and paying third parties to write fake reviews of products. In some cases, companies pay to write bad reviews for competitors' products. Twitter followers, Amazon reviews, and Facebook likes are all buyable by the thousand and it is estimated that 5% of product reviews on a large private label retailer's website are submitted by customers with no record of ever purchasing the product they are reviewing.

What it Does

StarCoin is a system that hopes to solve this problem by ensuring that:

  1. Only actual customers who have bought the product can review it
  2. Customers can only review products once
  3. Customers have to wait a specified amount of time after receiving the product before they can review it. Each purchase is tied to exactly one review, so all reviews for any product on this system would be legitimate.

How it Works

A smart contract was written in solidity and deployed onto the EVM of a Qtum blockchain. This contract allows for merchants to register their products into the distributed application. It then ensures that when one of their products is purchased, a review can only come from the address of the buyer, and only after a defined amount of time. This will make it so that buyer has time to experience the product before reviewing it. The buyer of the product will then be rewarded with StarCoin for writing helpful reviews. StarCoin could then be spent by consumers to get discounts on products, allowing merchants to reward their most valued customers. The contract uses a reveal-commit scheme to prevent censorship buy the merchant.


  • Writing secure and gas efficient smart contract
  • Setting up the private Qtum blockchain was difficult due to the lack of documentation as a result of it being so new.
  • Deploying and interacting with the contract using the Qtum cli.
  • Integrating ipfs into the web app.

Moving Forward

Store reviews using ipfs and access them on a web app using the hash of the review. This gets rid of the need for a centralized database and maintains that the application is completely decentralized.

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