Amazon DynamoDB Accelerator (DAX) now supports encryption in transit of data between your applications and DAX clusters, and between the nodes within a DAX cluster

You now can further enhance the security of your applications by encrypting data in transit between your applications and your Amazon DynamoDB Accelerator (DAX) clusters, and between the nodes within a DAX cluster. To use this new feature, enable encryption in transit when creating a DAX cluster and use the latest version of any of the DAX clients. If you enable encryption in transit for a DAX cluster, all requests and responses between your applications and clusters are encrypted by Transport Layer Security (TLS), and connections to the cluster can be authenticated by verification of a cluster X.509 certificate. In addition, the data in transit between the nodes within a cluster also is encrypted. You can enable encryption in transit in the DynamoDB console, AWS CLI, AWS SDKs, and AWS CloudFormation. 

Source:: Amazon AWS