What is CryptoWall & how does it work?

Could you elaborate on the nature and functionality of CryptoWall? As a cryptocurrency and finance expert, I'm interested in understanding how this particular ransomware operates. Specifically, I'd like to know how it encrypts files, demands a ransom payment, and how it communicates with its operators. Furthermore, are there any effective methods for prevention or mitigation should an individual or organization fall victim to this threat? I believe gaining this insight could help inform strategies for overall cybersecurity and risk management.