BoxCryptor is a great technology you can use to encrypt Dropbox files to ensure that only you and those you desire have full access to the stored files. It runs on Windows, Mac, Linux, iOS and Android. BoxCryptor allows you to set controls using set passwords to selectively protect sensitive data stored on Dropbox. This protection can target malicious individuals, people you don’t want to share sensitive files with and so much more. BoxCryptor is also very easy to use and install. Moreover, it has provisions for files up to 2GB in size.
The other tool which we highly recommend is TrueCrypt. It is open-source and very very secure.
So, we strongly suggest to configure boxCryptor or TrueCrypt so that all your very sensitive data is encrypted before that data is sync’d with Dropbox storage in the cloud.
Based on recent research, 40% of all data loss is caused by human error. And according to J. Reason (Human Error, 1990), humans prone to slips & lapses even on familiar tasks: 60% of errors are on “skill-based” automatic tasks.
On the other side, you should also protect your data against malicious deletion: hacker, virus, or disgruntled employee. For example, here is story of angry employee who deleted all company's data: Angry Employee Deletes All of Company's Data.
So BACKUP ALL YOUR DATA even if it is in the cloud.
cloudHQ is the perfect solution for this. cloudHQ can back up Dropbox data to Google Docs. Setup is very easy. The backup is actually done in real-time which means that as soon as data is changed in Dropbox it is transferred to Google Docs.
And since sync can be two-way, additional to backup you use cloudHQ to increase your productivity and simplify collaboration because documents from Google Docs will be also automatically sync’d with Dropbox.
Overall, cloudHQ is an amazing service you should try to sync your cloud services like Dropbox and Google docs, etc.
Setting up cloudHQ is easy: just select cloud accounts you want to sync and it is done. Set it and forget it.