Enables EBS encryption by default for your account in the current Region.
After you enable encryption by default, the EBS volumes that you create are are always encrypted, either using the default CMK or the CMK that you specified when you created each volume. For more information, see Amazon EBS Encryption
in the Amazon Elastic Compute Cloud User Guide
You can specify the default CMK for encryption by default using ModifyEbsDefaultKmsKeyId
Enabling encryption by default has no effect on the encryption status of your existing volumes.
After you enable encryption by default, you can no longer launch instances using instance types that do not support encryption. For more information, see Supported Instance Types