Our app runs on Amazon.com's AWS cloud. Many companies, banks, and governments run on AWS and trust it to be secure. To read more about AWS's security go to: http://aws.amazon.com/security/
We also have other layers of security on top of what AWS provides. For example, we only allow access to our apps over SSL encrypted connections and all of your files are encrypted when they are stored on Amazon's servers. We also do not store any passwords or credit card information on our system, which prevents this information from being exposed even if there was a data breach.
If there are any specific questions about security please contact us.