Which component is responsible for encrypting the virtual machine files?

The data encryption key (DEK) is essential for encrypting the virtual machine files. In a typical encryption framework, the DEK is used to encrypt and decrypt the data itself, which in this case consists of the virtual machine files. This key is crucial for protecting the confidentiality of the data stored in a virtual machine, ensuring that it remains secure from unauthorized access.

While certificate, key encryption key (KEK), and key management server (KMS) play roles in the encryption ecosystem, they do not directly encrypt the virtual machine files. The certificate can be used for identity verification and establishing trust, the KEK is primarily responsible for encrypting the DEK itself, and the KMS provides management services for storing and handling encryption keys. Thus, the DEK is the specific component that directly performs the encryption of virtual machine files, making it the correct choice in this context.