The Orchestration Server stores all user and agent passwords in its data store as double-hashed strings. User clients such as the zos command send the plain text password over a TLS encrypted authentication connection to obtain a randomly generated per-session credential issued by the server. This session credential is retained by the client, either in memory or in a temporary disk file for the duration of the session.
It is not possible to obtain the user’s password from the session credential, however. It should be protected to prevent unauthorized users from taking over the session. Agents send a singly hashed password as their login credential, which is in turn hashed once more on the server to authenticate new agent connections. Upon authentication, agents receive the same type of session credential as user clients.
Singly-hashed password strings are used as a special case for agents, because agents typically must store their plain text credentials to disk to allow the agents to start up on host or VM reboot. The use of a once hashed version of the password on the agent prevents administrators from compromising “user friendly” text passwords by storing them unhashed on agents. The use of single hashing on the agents and double hashing on the server database prevents stolen credential data from being used to obtain actual user or administrator-entered passwords