Sometimes AAM customers want to receive or send files to ftp-out.demdex.com or ftp-in.demdex.com using a secured connection, that is, insert RSA public keys on Audience Manager server to allow them key authentication.
If you add an RSA key or update one for Audience Manager, contact Customer Care at 'firstname.lastname@example.org' to request help.
Your customer Care representative does the necessary to inform Engineering of this request so that it gets processed.
The notion of private / public key is not isolated to Adobe processes. There is a lot of information around this in different places on the Internet, a good example being this page at https://kb.iu.edu/d/aews