NAT Gateway is a scalable and resilient method for allowing outbound internet traffic from your private VPC subnets.
It is recommended to use NAT gateways, and not the default route which permits all traffic, in Route Tables.
11. Under Preview Key Policy section, click Finish to create your new CMK. Once the key is created, the KMS dashboard will display a confirmation message: “Your master key was created successfully. Alias: MyEBSDataCMK”