SSH (Secure Shell) is a program for logging into and executing commands on a remote machine. It is intended to replace rsh (rlogin and rsh) and provides openssl (secure encrypted communication) between two untrusted hosts over an insecure network.

xorg-x11 (X Window System) connections and arbitrary TCP/IP ports can also be forwarded over the secure channel.

This alternative openssh package contains the HPN-13 (High Performance Networking) patches developed by the Web100 project: http://www.psc.edu/networking/projects/hpn-ssh/

It adds the following features:
- dynamic TCP windows
- "NONE" cipher for no encryption and high performance
- threaded CTR cipher mode (AES) for much higher throughput on multi-core systems (experimental)
- peak throughput: modifies the scp progress bar to display the 1 second throughput average; on completion of the transfer, it will display the peak throughput through the life of the connection