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Dropbox Head Responds To Snowden Claims About Privacy
First time accepted submitter Carly Page writes When asked for its response to Edward Snowden's claims that "Dropbox is hostile to privacy", Dropbox told The INQUIRER that users concerned about privacy should add their own encryption. The firm warned however that if users do, not all of the service's features will work. Head of Product at Dropbox for Business Ilya Fushman says: "We have data encrypted on our servers. We think of encryption beyond that as a users choice. If you look at our third-party developer ecosystem you'll find many client-side encryption apps....It's hard to do things like rich document rendering if they're client-side encrypted. Search is also difficult, we can't index the content of files. Finally, we need users to understand that if they use client-side encryption and lose the password, we can't then help them recover those files."
You realise dropbox is free, right? Why should they do something expensive like offer encryption on a service that is (a) free, and (b) for sharing files. Sharing's hard if your stuff is encrypted, and sharing is the source of most of Dropbox's value.
If you want encryption, then fine, do it yourself. You obviously know that your stuff won't be indexable or shareable so won't be calling for support or slagging Dropbox off online when you find indexing and sharing not working.
There's room to suggest Dropbox should offer a pay-for encrypted service. The thing is, no matter how well they do it, it'll always be vulnerable to government interference, and it'll never be fully trusted anyway. BYO means no government interference and trust *for the relatively small number of people who care* without raising the costs too much for the multitudes who don't.
You do realize there are several flavors of encryption, right? Microsoft SQL Server TDE is an example. You can login, perform queries, update data in any table, but all data is encrypted - it is - transparent as the name indicates.
That also ignores things like encrypted volumes, etc. Just because individual files aren't encrypted with unique keys, doesn't mean that encryption isn't there.
As long as you still trust TrueCrypt, there's no reason you shouldn't use an encrypted container file (or multiple smaller containers) in your Dropbox. Some people might not know this, but Dropbox only re-uploads the parts of the file that change (it does a binary comparison), and TrueCrypt typically only updates relatively small sections of the container file when you add/remove/modify a file in the container, so it doesn't take much bandwidth except for the initial upload. Just make sure you dismount frequently enough to allow Dropbox to sync when you make changes. (I'd recommend setting TrueCrypt to automatically dismount after an hour or so of no data being read/written.)
You could use the dynamic disk option when creating the TC container to save bandwidth during the initial upload, if you're starting with an empty container (the size of the container will change, up to a set maximum, to match the contents), but that will have other performance penalties when using the container, and it brings with it the increased risks. In particular, it makes it possible for an analyst to get some idea of how you are storing files in the container, potentially making it easier to break the encryption.
And since it's being stored in the cloud, you should maximize your security by using local keyfiles/tokens rather than a single password. You might as well assume that the whole world has a copy of the container.
For convenience, you can store a portable unencrypted copy of TrueCrypt in Dropbox as well, but you should really only do that if you keep a local copy of the checksums for the binaries and compare them to the files whenever you run them. (That will ensure that nobody has accessed your account and replaced your portable TC binaries with compromised versions capable of stealing your keys.) Or carry a portable version on a USB drive.
The only downside I can see to this is that if you need access to your files on a new machine, you will need to download the whole container, and if the new machine is compromised, you could have your keys stolen. Even so, it's much more secure than using Dropbox on its own, and in my opinion, it's worth the potential inconvenience to have good encryption and cloud access.
If you use their web interface, they will store your password on their servers. Be aware of that.
Also, your account password is the the key used to encrypt your data (easy to verify: accessing your data on a new device only requires your account password). They use PDKDF2, which expands the password into a larger key, but (obviously) doesn't add any entropy to that already present in the password. Choose your password wisely.
That password is also used to access the billing, etc web interface, so they do keep at least a hashed copy of your password on their servers.
As with any closed source and opaque solution, you shouldn't depend in any way on unverifiable claims. They could now, or at any time in the future, store your passwords. You're better off handling your own security than trusting magic black boxes.
If you want a vision of the future, imagine a youtube comments section scrolling - forever.