---
name: "secsh"
section: "5"
platform: "linux"
package: "lsh-doc"
version: "2.1-13"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/secsh"
---

# secsh(5)

the Secure Shell protocol

## NAME

secsh - the Secure Shell protocol

## DESCRIPTION

**secsh** is a protocol suite for secure remote login and other secure network services over an insecure network. It is outlined in **\[SECSH\]**. It has three major components:

- The Transport layer protocol

  This protocol, specified in **\[SECSH-TLP\]**, provides server authentication, confidentiality, and integrity with perfect forward secrecy.

- The User authentication protocol

  This protocol, specified in **\[SECSH-AUTH\]**, is used to authenticate a client to a server.

- The Connection protocol

  This protocol, specified in **\[SECSH-CONN\]**, multiplexes an encrypted tunnel into several logical channels.

## IMPLEMENTATIONS

Several implementations of the secsh protocol suite exist.

The  **SSH2** product of SSH Communications Security Ltd., Finland \<URL:http://www.ssh.fi\> was the first. The secsh protocol suite has benefited a lot from their experience with their older SSH1 product, which is still in widespread use; it implements an older protocol (**\[SSH1\]**).

The **lsh** suite of programs is a free implementation of the secsh protocol suite; it is distributed under the GNU General Public License.

## REFERENCES

**\[SECSH-ARCH\]** T. Ylonen, T. Kivinen, M. Saarinen, T. Rinne and S. Lehtinen, *SSH Protocol Architecture*, Internet draft, 6 August 1998

**\[SECSH-TRANS\]** T. Ylonen, T. Kivinen, M. Saarinen, T. Rinne and S. Lehtinen, *SSH Transport Layer Protocol*, Internet draft, 6 August 1998

**\[SECSH-AUTH\]** T. Ylonen, T. Kivinen, M. Saarinen, T. Rinne and S. Lehtinen, *SSH Authentication Protocol*, Internet draft, 6 August 1998

**\[SECSH-CONN\]** T. Ylonen, T. Kivinen, M. Saarinen, T. Rinne and S. Lehtinen *SSH Connection Protocol*, Internet draft, 6 August 1998

**\[SSH1\]** T. Ylonen, *The SSH (Secure Shell) Remote Login Protocol*, Internet draft (expired), 15 November 1995

## TRADEMARKS

SSH and Secure Shell are trademarks or registered trademarks of SSH Communications Security Ltd.

## AUTHOR

This man-page was written by J.H.M. Dassen (Ray) \<jdassen@wi.LeidenUniv.nl\>.

## SEE ALSO

[**lsh**(1)](/lsh/1.md), [**lshd**(8)](/lshd/8.md), **ssh2**(1), **sshd2**(8), [**ssh1**(1)](/ssh1/1.md), **sshd1**(8)