You may, as I did, wonder just how secure your data on Dropbox is. Can the guys and gals at Dropbox read what’s inside your super-secret file? What happens if you, or someone you’re sharing a folder with, accidentally deletes something important? Where are your files actually kept?

These excerpts from the Dropbox website should help explain…

Dropbox uses Amazon’s Simple Storage Service (S3) for storage.  Amazon have a robust security policy, which you can read about in their Overview of Security Processes document.  Apart from physical security, there are also other technical security precautions in place to prevent unauthorized access to data.

Back to Dropbox… they say:

Nobody can see your private files in Dropbox unless you deliberately invite them or put them in your Public folder. Everything in your Public folder is, by definition, accessible to anyone. Otherwise, the only way to access the files in your Dropbox online is with your username and password.

Here are the key points in their “Advanced Users” section:

Dropbox uses modern encryption methods to both transfer and store your data.

• All transmission of file data and metadata occurs over an encrypted channel (SSL).
• All files stored on Dropbox servers are encrypted (AES-256) and are inaccessible without your account password
• Public files are only viewable by people who have a link to the file(s). Public folders are not browsable or searchable
• Dropbox employees aren’t able to access user files, and when troubleshooting an account they only have access to file metadata (filenames, file sizes, etc., not the file contents)

This was enough to satisfy me, although I don’t store my most important files on there. (Perhaps I should!)

To answer questions I posed at the start…

1. Can the guys and gals at Dropbox read what’s inside your super-secret file? No (see above)
2. What happens if you, or someone you’re sharing a folder with, accidentally deletes something important?
   Dropbox keeps snapshots of every saved change in your Dropbox folder over the last 30 days.  So you can restore deleted files with a few clicks.
   Dropbox also keeps a hidden collection, or cache, of your files (in your Dropbox application settings) as backup storage . Files in the cache folder are stored there often after they are moved or deleted after syncing. If you can’t find your file using all other practical methods, you can try to recover the file from Dropbox cache as a last resort. The Dropbox cache will keep files for up to 3 days after they have been moved or deleted.
3. Where are your files actually kept?
   If you’ve installed the Dropbox desktop application, your files are stored both on your computer (in your Dropbox folder) and on Dropbox’s secure online servers in data centers located along the east coast of the United States.