6.5.1

Table Of Contents
How vSphere Virtual Machine Encryption Protects Your
Environment
With vSphere Virtual Machine Encryption, you can create encrypted virtual machines and encrypt existing
virtual machines. Because all virtual machine files with sensitive information are encrypted, the virtual
machine is protected. Only administrators with encryption privileges can perform encryption and
decryption tasks.
What Keys Are Used
Two types of keys are used for encryption.
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The ESXi host generates and uses internal keys to encrypt virtual machines and disks. These keys
are used as DEKs and are XTS-AES-256 keys.
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vCenter Server requests keys from the KMS. These keys are used as the key encryption key (KEK)
and are AES-256 keys. vCenter Server stores only the ID of each KEK, but not the key itself.
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ESXi uses the KEK to encrypt the internal keys, and stores the encrypted internal key on disk. ESXi
does not store the KEK on disk. If a host reboots, vCenter Server requests the KEK with the
corresponding ID from the KMS and makes it available to ESXi. ESXi can then decrypt the internal
keys as needed.
What Is Encrypted
vSphere Virtual Machine Encryption supports encryption of virtual machine files, virtual disk files, and
core dump files.
Virtual machine files Most virtual machine files, in particular, guest data that are not stored in the
VMDK file, are encrypted. This set of files includes but is not limited to the
NVRAM, VSWP, and VMSN files. The key that vCenter Server retrieves
from the KMS unlocks an encrypted bundle in the VMX file that contains
internal keys and other secrets.
If you are using the vSphere Web Client to create an encrypted virtual
machine, all virtual disks are encrypted by default. For other encryption
tasks, such as encrypting an existing virtual machine, you can encrypt and
decrypt virtual disks separate from virtual machine files.
Note You cannot associate an encrypted virtual disk with a virtual machine
that is not encrypted.
Virtual disk files Data in an encrypted virtual disk (VMDK) file is never written in cleartext to
storage or physical disk, and is never transmitted over the network in
cleartext. The VMDK descriptor file is mostly cleartext, but contains a key
ID for the KEK and the internal key (DEK) in the encrypted bundle.
vSphere Security
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