I believe the answer to this question is no, it is not required. But I am only an entry level manager of SharePoint 2013 and would appreciate confirmation from more knowledgeable people.
In this system, SharePoint is used in conjunction with TFS2013. The TFS server is being transferred to a new domain. Part of the instructions at this link for the transfer include how to transfer SharePoint and one step in the process includes the encryption key.
I believe I do not need to perform this step because I don't recall ever specifying an encryption key previously.
But I would like to get confirmation on this. Is there a way to confirm if an encryption key exists?