Secrets management and encryption at rest
(New in Docker Engine 1.13)
Secrets management = selectively and securely bring secrets to services
Encryption at rest = protect against storage theft or prying
Remember:
control plane is authenticated through mutual TLS, certs rotated every 90 days
control plane is encrypted with AES-GCM, keys rotated every 12 hours
data plane is not encrypted by default (for performance reasons),
but we saw earlier how to enable that with a single flag