OpenSSH stands for Open Secure Shell, a set of computer programs providing encrypted communication sessions over a computer network.

OpenSSH was created by the OpenBSD team as an open alternative to SSH, which is now proprietary software. Its developers claim that OpenSSH is more secure than the original, partly due to the reputation of the OpenBSD developers in emphasising clean and well-audited code, which in turn contributes to security. Its security is further attributed to the fact that its source code is released under an Open Source license, the BSD license (to which the "Open" in the name refers). Although source code is available for the original SSH, various restrictions are imposed on its use and distribution, making OpenSSH a more attractive project for many software developers.

Since OpenSSH performs authentication, in particular, it runs into a lot of differences between operating systems. The OpenSSH Portability Team is responsible for adding code necessary for portability and issuing "Portable releases".

The OpenSSH suite includes:

  • sshd (the SSH daemon)
  • ssh (replaces rlogin and telnet)
  • scp (replaces rcp)
  • sftp (replaces ftp)

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