It is unclear what question you are asking, that is if you are asking a question.
If you invoke the service API with HTTPS, then all the data will be encrypted while it is flowing over SSL. Once with the service, it will be stored in a database, I wouldn't think that it would be encrypted, but access to the database will be controlled.
You need to get the data from / to the Conversation service API. Which you might do from a HTTP form. This transport layer is outside the control of the Conversation API, so it is up to you to ensure the channel is secured. This will also be the most vulnerable channel in your application architecture.