With the rising interest in social media and file-and video-sharing applications, the demand for storage platforms has increased significantly. In these applications, our data are stored on centralized storage platforms owned and operated by giant service providers. These platforms, however, have been facing problems such as data breaches, data outrages, rising storage costs, lack of ownership, censorship, and monitoring. A new concept of a decentralized storage platform has emerged to solve these issues. Several platforms have been devised based on this concept. In this study, we aim to present a survey of the leading decentralized storage platforms currently implemented on the Internet. To this end, we first derived the requirements and four essential elements of a decentralized storage platform. We then investigated the major leading decentralized storage platforms in terms of blockchain usage, data decentralization method, data encryption method, and data integrity verification. As a result, we found that a decentralized storage platform requires an extra function of security and protection for data and has the potential to provide self-sovereign data.