OpenSSH

OpenSSH stands for "Open Secure SHell," and it is sometimes referred to as "secure shell." Unlike TLS and IPSec, OpenSSH is not a formalized standard, but it is used widely in the IP community and consequently it was ported to the z/OS platform. As of the time of writing, the IETF is working on producing RFCs to standardize OpenSSH.

On z/OS, OpenSSH consists of:

Secure FTP (sftp): The sftp client and sftp daemons provide secure FTP-like functionality.
Secure copy (scp): The scp command is a secure alternative for the remote copy program, rcp.
Remote login (ssh): The ssh command functions similarly to the remote login (rlogin) command or remote shell (rsh) commands. The daemon end is supported by the secure shell daemon, sshd.

OpenSSH on z/OS is the same as you would expect to find on any UNIX-like platform.