Is there any function of Couchbase like Oracle Transparent Data Encryption?

I’m just trying Couchbase for a membership service system on AWS.
Because i need to store user profile data in couchbase, but don’t want to make my application very complicated, so just hope there is a suitable function already implemented with the newest version.

I have checked Firewall And Secure XDCR in Couch 3.0.1 and some articles about Securing data communication, but it seems only encrypt data on traffic, not sure that which format (encrypted or not) a data will be saved in a couchbase node.

You are correct XDCR data can be encrypted. In Couchbase 3.0 data can be encrypted from App servers to Couchbase server too. Currently inter-cluster, traffic between a nodes, communication is not encrypted, but if your cluster is in its own VLAN you should be ok. Here are all the ports you need