Webex Teams security functions by using a Key Management Service (KMS) to handle and distribute encryption keys securely. The KMS is responsible for generating, storing, and providing access to encryption keys, ensuring that all data, including messages, files, and content within Webex Teams, is encrypted both at rest and in transit. This method ensures that only authorized users have access to the content, and even Cisco itself cannot decrypt the data without the appropriate keys, providing end-to-end security and privacy.