Dropbox

Each file uploaded to Dropbox are secured in blocks at a separate server before being transferred into the storage servers. All files are encrypted with a unique cipher during processing in the block servers. When content in files are modified, the changed information would be transmitted to the block server prior to being sent to storage. Files in Dropbox contain metadata – which are basic information such as date uploaded and modified as well file names – where they would be kept on a separate metadata server for database purposes. Any changes to files – deletion, modification, or otherwise – would be alerted to users with file access through the notification service. Dropbox maintains its own data storage servers called Magic Pocket where around 90% of users’ files are kept, although until 2016, the company exclusively used Amazon Web ServicesAmazon Web Services’ cloud storage.