From the OCR website: 

We are experiencing an explosion of technology using data about the health of individuals in innovative ways to improve health outcomes. Building privacy and security protections into technology products enhances their value by providing some assurance to users that the information is safe and secure and will be used and disclosed only as approved or expected. Such protections are sometimes required by federal and state laws, including the HIPAA Privacy, Security and Breach Notification Rules.

From the OCR website:

A “business associate” is a person or entity, other than a member of the workforce of a covered entity, who performs functions or activities on behalf of, or provides certain services to, a covered entity that involve access by the business associate to protected health information.  A “business associate” also is a subcontractor that creates, receives, maintains, or transmits protected health information on behalf of another business associate.