Dropbox has suffered through a number of security- and privacy-related incidents over the past year, which has left its frustrated but loyal userbase asking how they can continue using Dropbox while still properly securing their data.
SecretSync, a new startup, hopes to be the answer to that question. SecretSync encrypts sensitive data that you place in Dropbox so that, in the event Dropbox releases your files to law enforcement agencies or inadvertently makes your data public, you have nothing to worry about: your data will be completely inscrutable thanks to the client-side encryption used by SecretSync. Because your data is encrypted before it leaves your computer, client side encryption means you can safely store your data with a third party that you don't necessarily trust.
Unlike other client-side encryption solutions, such as TrueCrypt, SecretSync is designed from the ground up to work transparently with Dropbox. You don't need to tweak or customize Dropbox in any way – just install SecretSync, and any sensitive data you place in your new SecretSync folder will be transparently encrypted and synchronized with the SecretSync folders on your other computers.
Security does come at a price though, both in financial terms and in lost Dropbox functionality: the service is free for up to 2GB of data, but costs $39.99 – 59.99/year if your storage requirements are higher; also, files stored in SecretSync cannot be shared via Dropbox's web interface with other users.