WordPress upload file names can be quite predictable sometimes, especially if uploading from the same camera – DKIM1004 comes after DKIM1003. If not all of the content on your site is public, this can be a problem as people can snoop on your media folder by guessing file names.
This plugin prepends a short 8 character hash to the beginning of every uploaded file. For example, DKIM1004.jpg turns into 8df8078e-DKIM1004.jpg. The hash is not cryptographically secure and just makes it a bit more difficult to guess file names.
The plugin works on all upload file types and all sizes of a given image get the same prefix.