Final answer:
Before 2009, the Centers for Medicare & Medicaid Services (CMS) was in charge of overseeing and enforcing the HIPAA Security Rule, which aimed to protect electronic Protected Health Information.
Step-by-step explanation:
The entity responsible for the oversight and enforcement of the Security Rule before 2009 was the Centers for Medicare & Medicaid Services (CMS). The Security Rule is a part of the Health Insurance Portability and Accountability Act (HIPAA) of 1996, which specifies a series of administrative, physical, and technical safeguards for protecting electronic Protected Health Information (ePHI).
In 2009, the responsibility for enforcing the Security Rule was transferred to the Office for Civil Rights (OCR) as a part of the Health Information Technology for Economic and Clinical Health (HITECH) Act.