Research On Privacy Issues In User Generated Content System Based On Blockchain

With the continuous development of the digital age,widely-concerned theoretical research on blockchain technology emerges.In the era of blockchain 3.0,various industries expect blockchain to bring brand-new solutions to their pain points in certain actual business scenarios.As a "content community",the user generated content system provides a platform for users on the Internet to express opinions,create art,and share experiences.Blockchain technology can be combined with the user generated content system.And the content data released by users in the latter is stored on the chain.At the same time,economic value of the token is used to incentivize users,so that users can truly obtain the ownership and benefit of the content data.While blockchain technology brings new features to the user generated content system,it also brings privacy challenges.For example,when the blockchain network node verifies the signature,it will obtain the correspondence between the user's public key and the signature;the blockchain browser will expose the sensitive asset information of the user whose address is reused in the system.The existing blockchain privacy protection scheme is not suitable for the protection of user privacy in specific business scenarios of the user generated content system.In order to deal with the above problems,this paper gives the scope of privacy issues in the blockchain-based user generated content system,and focuses on user identity privacy and user account privacy.The main work is as follows:(1)This research paper studies the contradiction between user identity privacy issues and actual supervision requirements,and a group signature privacy protection scheme with supervision characteristics is proposed.Use the group signature algorithm instead of the conventional ECDSA algorithm or the ring signature algorithm commonly used in anonymous coins,that is,use a fixed group public key when verifying the signature,instead of the user public key that identifies the user or the userdefined public key ring,to hide the relationship between user and the signature,while retaining the ability to track the user's identity.(2)In order to solve the problem of excessive concentration of privileges of special participants in the system,this paper incorporates threshold secret sharing technology into the group signature scheme described in(1)above to realize privilege management.The scheme sees the group private key used in the signature opening algorithm as a secret and shares it with multiple system administrators.Only when the number of administrators meeting the threshold requirement jointly decide to open a certain signature,can the group private key be reconstructed and the signature opening algorithm can be run correctly.(3)This paper studies the user account privacy issues caused by the reuse of blockchain addresses,and improves two existing stealth address schemes based on the UTXO model,so that they can operate under the account-balance model,which is suitable for the blockchain-based user generated content system based on the accountbalance model.(4)In order to test the feasibility and performance of the above privacy protection scheme,we built a blockchain using the Cosmos SDK,designed and implemented a blockchain-based user generated content system,and applied the above scheme to the experimental system.Experimental results show that the above privacy protection scheme can protect user identity privacy and user account privacy without increasing the technical threshold for users to use the system and without reducing user experience.