Hazelcast is a distributed in-memory data grid, which allows to evenly share data among nodes in clustered environments. The open source version of Hazelcast does not support encryption at the transport or even at the cache level. So in order to secure traffic in the Hazelcast cluster, we need to extend it by making some code changes, which may not always be an option.
There is however another way to secure the transport by using stunnel. As the official documentation states, “Stunnel is a proxy designed to add TLS encryption functionality to existing clients and servers without any changes in the programs’ code”. This sounds like a perfect option in our case, and allows us to decouple transport encryption from our Hazelcast applications.