Decentralized Privacy Protection Approach for Video Surveillance Service

Cloud-based video surveillance service is being deployed ubiquitously, and the service normally stores video streams in the cloud over the Internet. The main problem of this service is that the user never knows how secure the video stream is transferred and stored. Although the video contains sensitive data that is related to personal or area-specific information, there is no way to objectively check whether the video is securely managed. Therefore, a user must trust that the service provider will keep their video secure without any evidence. Ensuring confidential information and privacy is protected, the sensitive data should be encrypted and traceable when they are transferred. In this paper, an architecture to build a key management system based on blockchain and public-key cryptography is proposed. The video encryption is possible by a block-cipher algorithm with a given symmetric key. In the proposed system, the symmetric key is also encrypted by a public key and stored as a ledger in the blockchain. Thus, when the symmetric key is requested, every operation is traceable, so a user can trust how a video stream is transferred and stored securely because of the nature of blockchain, decentralization, transparency, and the impossibility of being tempered. In addition, the user can monitor the request flow of the key, and then, the key is selectively distributable by the user’s intention. Therefore, the system meets the requirement of a fully secure method to manage the whole life cycle of video from creation to deletion. In this paper, we propose to apply this architecture to video surveillance service and also extend them to general-purpose systems.