Secure Shell or SSH is a network protocol that allows data to be exchanged over a secure channel between two computers. Encryption provides confidentiality and integrity of data. SSH uses public-key cryptography to authenticate the remote computer and allow the remote computer to authenticate the user, if necessary. In computing and telecommunications, the transport layer is the second highest layer in the four and five layer TCP/IP reference models, where it responds to service requests from the application layer and issues service requests to the Internet layer. ... The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite. ... User Datagram Protocol (UDP) is one of the core protocols of the Internet protocol suite. ... The Datagram Congestion Control Protocol (DCCP) is a message-oriented transport layer protocol that is currently under development in the IETF. Applications that might make use of DCCP include those with timingconstraints on the delivery of data such that reliable in-order delivery, when combined with congestion control, is likely... In the field of computer networking, the IETF Signaling Transport (SIGTRAN) working group defined the Stream Control Transmission Protocol (SCTP) as a transport layer protocol in 2000. ... The Real-time Transport Protocol (or RTP) defines a standardized packet format for delivering audio and video over the Internet. ... The Resource ReSerVation Protocol (RSVP), described in RFC 2205, is a Transport layer protocol designed to reserve resources across a network for an integrated services Internet. ... The Internet Group Management Protocol (IGMP) is a communications protocol used to manage the membership of Internet Protocol multicast groups. ... The network layer is third layer out of seven in OSI model and it is the third layer out of five in TCP/IP model. ... The Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork. ... Internet Protocol version 4 is the fourth iteration of the Internet Protocol (IP) and it is the first version of the protocol to be widely deployed. ... Internet Protocol version 6 (IPv6) is a network layer protocol for packet-switched internetworks. ... The Open Shortest Path First (OSPF) protocol is a hierarchical interior gateway protocol (IGP) for routing in Internet Protocol, using a link-state in the individual areas that make up the hierarchy. ... Is Is is Yeah Yeah Yeahs third EP, to be released on July 24, 2007. ... The Border Gateway Protocol (BGP) is the core routing protocol of the Internet. ... IPsec (IP security) is a suite of protocols for securing Internet Protocol (IP) communications by authenticating and/or encrypting each IP packet in a data stream. ... In computer networking, the Address Resolution Protocol (ARP) is the standard method for finding a hosts hardware address when only its network layer address is known. ... Reverse Address Resolution Protocol (RARP) is a network layer protocol used to obtain an IP address for a given hardware address (such as an Ethernet address). ... This article is chiefly about the Routing Information Protocol (RIP) for the Internet Protocol, but also discusses some other routing information protocols. ... The Internet Control Message Protocol (ICMP) is one of the core protocols of the Internet protocol suite. ... The ICMP for IPv6 (Internet Control Message Protocol Version 6) is an integral part of the IPv6 architecture and must be completely supported by all IPv6 implementations. ... This article does not cite any references or sources. ... IEEE 802. ... The IEEE 802. ... Official Wi-Fi logo Wi-Fi (pronounced wye-fye, IPA: ) is a wireless technology brand owned by the Wi-Fi Alliance intended to improve the interoperability of wireless local area network products based on the IEEE 802. ... Official WiMax logo WiMAX, the Worldwide Interoperability for Microwave Access, is a telecommunications technology aimed at providing wireless data over long distances in a variety of ways, from point-to-point links to full mobile cellular type access. ... Asynchronous Transfer Mode (ATM) is a cell relay, packet switching network and data link layer protocol which encodes data traffic into small (53 bytes; 48 bytes of data and 5 bytes of header information) fixed-sized cells. ... Dynamic synchronous Transfer Mode , or DTM for short, is a network protocol. ... Token-Ring local area network (LAN) technology was developed and promoted by IBM in the early 1980s and standardised as IEEE 802. ... Ethernet is a large, diverse family of frame-based computer networking technologies that operate at many speeds for local area networks (LANs). ... In computer networking, fiber-distributed data interface (FDDI) is a standard for data transmission in a local area network that can extend in range up to 200 km (124 miles). ... In the context of computer networking, frame relay consists of an efficient data transmission technique used to send digital information quickly and cheaply in a relay of frames to one or many destinations from one or many end-points. ... General Packet Radio Service (GPRS) is a Mobile Data Service available to users of Global System for Mobile Communications (GSM) and IS-136 mobile phones. ... Evolution-Data Optimized or Evolution-Data only, abbreviated as EV-DO or EVDO and often EV, is one telecommunications standard for the wireless transmission of data through radio signals, typically for broadband Internet access. ... High-Speed Packet Access (HSPA) is a collection of mobile telephony protocols that extend and improve the performance of existing UMTS protocols. ... High-Level Data Link Control (HDLC) is a bit-oriented synchronous data link layer protocol developed by the International Organization for Standardization (ISO). ... In computing, the Point-to-Point Protocol, or PPP, is commonly used to establish a direct connection between two nodes. ... The Point-to-Point Tunneling Protocol (PPTP) is a method for implementing virtual private networks. ... In computer networking, the Layer 2 Tunneling Protocol (L2TP) is a tunneling protocol used to support virtual private networks (VPNs). ... ISDN redirects here. ... This article does not cite any references or sources. ... IEEE photograph of a diagram with the original terms for describing Ethernet drawn by Robert M. Metcalfe around 1976. ... For other uses, see Modem (disambiguation). ... For other uses, see Power band. ... It has been suggested that this article be split into articles entitled Synchronous optical networking, SONET and Synchronous digital hierarchy. ... There are very few or no other articles that link to this one. ... Optical fibers An optical fiber (or fibre) is a glass or plastic fiber designed to guide light along its length. ... Coaxial Cable For the weapon, see coaxial weapon. ... 25 Pair Color Code Chart 10BASE-T UTP Cable Twisted pair cabling is a common form of wiring in which two conductors are wound around each other for the purposes of cancelling out electromagnetic interference known as crosstalk. ... SSH refers to: Secure Shell, network protocol social sciences and humanities, term used to describe broad field of research SSH Communications Security, Finnish company that developed the Secure Shell protocol SSH Swiss School of Hotel and Tourism Management, college of Applied Science at the SSTH Swiss School of Tourism and... In computing, a shell is a piece of software that provides an interface for users (command line interpreter). ... In networking, a communications protocol or network protocol is the specification of a set of rules for a particular type of communication. ... In cryptography, and particularly in analytic or academic discussions of it, a secure channel is a method or technique assumed to provide means by which data can be transferred from one place or user to another without risk of interception or tampering. ... Encrypt redirects here. ... A big random number is used to make a public-key pair. ... For other uses of the terms authentication, authentic and authenticity, see authenticity. ...

SSH is typically used to log into a remote machine and execute commands, but it also supports tunneling, forwarding arbitrary TCP ports and X11 connections; it can transfer files using the associated SFTP or SCP protocols. A tunneling protocol is a network protocol which encapsulates one protocol or session inside another. ... The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite. ... It has been suggested that this article or section be merged into Computer port (software). ... In computing, the X Window System (commonly X11 or X) is a windowing system for bitmap displays. ... In computing, the SSH File Transfer Protocol or SFTP is a network protocol that provides file transfer and manipulation functionality over any reliable data stream. ... Secure Copy or SCP is a means of securely transferring computer files between a local and a remote host or between two remote hosts, using the Secure Shell (SSH) protocol. ...

An SSH server, by default, listens on the standard TCP port 22. In information technology, a server is an application or device that performs services for connected clients as part of a client-server architecture. ... It has been suggested that this article or section be merged with Port numbers. ...

An ssh client program is typically used for establishing connections to an sshd daemon accepting remote connections. Both are commonly present on most modern operating systems, including Mac OS X, Linux, Solaris and OpenVMS. Proprietary, freeware and open source versions of various levels of complexity and completeness exist. In computing, a client is a system that accesses a (remote) service on another computer by some kind of network. ... In Unix and other computer multitasking operating systems, a daemon is a computer program that runs in the background, rather than under the direct control of a user; they are usually instantiated as processes. ... In computing, an operating system (OS) is the system software responsible for the direct control and management of hardware and basic system operations. ... Mac OS X (pronounced ) is a line of graphical operating systems developed, marketed, and sold by Apple Inc. ... This article is about operating systems that use the Linux kernel. ... Solaris is a computer operating system developed by Sun Microsystems. ... OpenVMS[1] (Open Virtual Memory System or just VMS) is the name of a high-end computer server operating system that runs on the VAX[2] and Alpha[3] family of computers developed by Digital Equipment Corporation of Maynard, Massachusetts (DIGITAL was then purchased by Compaq, and is now owned... Proprietary software is software with restrictions on copying and modifying as enforced by the proprietor. ... The term Freeware refers to gratis proprietary software with closed source. ... Open source software is computer software which source code is available under a license (or arrangement such as the public domain) that meets the Open_source_definition. ...

History

In 1995, Tatu Ylönen, a researcher at Helsinki University of Technology, Finland, designed the first version of the protocol (now called SSH-1) prompted by a password-sniffing attack at his university network. The goal of SSH was to replace the earlier rlogin, TELNET and rsh protocols, which did not provide strong authentication or guarantee confidentiality. Ylönen released his implementation as freeware in July 1995, and the tool quickly gained in popularity. Towards the end of 1995, the SSH user base had grown to 20,000 users in fifty countries. Helsinki University of Technology (TKK) (Finnish: Teknillinen korkeakoulu; Swedish: Tekniska högskolan) is the premier technical university in Finland and the largest in the Nordic Countries with over 15000 students. ... A campus area network (CAN) is a computer network made up of an interconnection of local area networks (LANs) within a limited geographical area. ... In computing, rlogin is a Unix software utility that allows users to log in on another host via a network, communicating via TCP port 513. ... For the packet switched network, see Telenet. ... rsh (remote shell) is a command line computer program which can execute shell commands as another user, and on another computer across a computer network. ... The term Freeware refers to gratis proprietary software with closed source. ...

In December 1995, Ylönen founded SSH Communications Security to market and develop SSH. The original version of the SSH software used various pieces of free software, such as GNU libgmp, but later versions released by SSH Secure Communications evolved into increasingly proprietary software. SSH Communications Security is a Finnish company thats based in Helsinki and was founded by Tatu Ylönen in 1995. ... Free software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions only to ensure that further recipients can also do these things. ... The GNU Multiple-Precision Library, also known as GMP, is a free library for arbitrary precision arithmetic, operating on signed integers, rational numbers, and floating point numbers. ... Proprietary software is software with restrictions on copying and modifying as enforced by the proprietor. ...

In 1996, a revised version of the protocol, SSH-2, was designed, incompatible with SSH-1. SSH-2 features both security and feature improvements over SSH-1. Better security, for example, comes through Diffie-Hellman key exchange and strong integrity checking via message authentication codes. New features of SSH-2 include the ability to run any number of shell sessions over a single SSH connection.^[1] Diffie-Hellman (D-H) key exchange is a cryptographic protocol that allows two parties that have no prior knowledge of each other to jointly establish a shared secret key over an insecure communications channel. ... This article is about the ethical concept. ... A cryptographic message authentication code (MAC) is a short piece of information used to authenticate a message. ...

In 1999, developers wanting a free software version to be available went back to the older 1.2.12 release of the original ssh program, which was the last released under an open source license. Björn Grönvall's OSSH was subsequently developed from this codebase. Shortly thereafter, OpenBSD developers forked Björn's code and did extensive work on it, creating OpenSSH, which shipped with the 2.6 release of OpenBSD. From this version, a "portability" branch was formed to port OpenSSH to other operating systems. Open source refers to projects that are open to the public and which draw on other projects that are freely available to the general public. ... OpenBSD is a Unix-like computer operating system descended from Berkeley Software Distribution (BSD), a Unix derivative developed at the University of California, Berkeley. ... In software engineering, a project fork or branch happens when a developer (or a group of them) takes a copy of source code from one software package and starts to independently develop a new package. ... OpenSSH (Open Secure Shell) is a set of computer programs providing encrypted communication sessions over a computer network using the SSH protocol. ...

It is estimated that, at the end of 2000, there were 2,000,000 users of SSH.^[2] This article is in need of attention. ...

As of 2005, OpenSSH is the single most popular ssh implementation, coming by default in a large number of operating systems. OSSH meanwhile has become obsolete.^[3] 2005 is a common year starting on Saturday of the Gregorian calendar. ...

In 2006, the aforementioned SSH-2 protocol became a proposed Internet standard with the publication by the IETF "secsh" working group of RFCs (see references). An Internet standard is a specification for an innovative internetworking technology or methodology, which the Internet Engineering Task Force (IETF) ratified as an open standard after the innovation underwent peer review. ... The Internet Engineering Task Force (IETF) is charged with developing and promoting Internet standards. ... Wikipedia does not have an article with this exact name. ... In internetworking and computer network engineering, Request for Comments (RFC) documents are a series of memoranda encompassing new research, innovations, and methodologies applicable to Internet technologies. ...

Uses of SSH

Example of tunneling an X11 application (xeyes) over SSH.

SSH is most commonly used: Image File history File links Download high resolution version (1024x768, 244 KB) Summary Example of remotely running an X11 program through SSH tunnelling. ... Image File history File links Download high resolution version (1024x768, 244 KB) Summary Example of remotely running an X11 program through SSH tunnelling. ...

• with an SSH client that supports terminal protocols, for remote administration of the SSH server computer via terminal (character-mode) console--can be used as an alternative to a terminal on a headless server;
• In combination with SFTP, as a secure alternative to FTP which can be set up more easily on a small scale without a public key infrastructure and X.509 certificates;
• in combination with rsync to backup, copy and mirror files efficiently and securely
• in combination with SCP, as a secure alternative for rcp file transfers—more often used in environments involving Unix
• for port forwarding or tunneling, frequently as an alternative to a full-fledged VPN. In this type of use, a (non-secure) TCP/IP connection of an external application is redirected to the SSH program (client or server), which forwards it to the other SSH party (server or client), which in turn forwards the connection to the desired destination host. The forwarded connection is encrypted and protected on the path between the SSH client and server only. Uses of SSH port forwarding include accessing database servers, email servers, securing X11, Windows Remote Desktop and VNC connections or even forwarding Windows file shares. This is primarily useful for tunneling connections through firewalls which would ordinarily block that type of connection, and for encrypting protocols which are not normally encrypted (e.g. VNC).
• ssh and rdesktop. Three computers, the computer that will run rdesktop and ssh, a computer used to obtain access to a remote network, and the last will be the computer you want rdesktop to display. "ssh -L3389:mytarget.mycompany.net:3389 sshtarget.mycompany.net". Just log into the middle computer and do nothing on it. Open another shell from the first computer running ssh and type rdesktop localhost. This example uses the middle computer to port forward 3389 from the end computer to the first computer. If on Windows, run ssh using another local port, e.g. "ssh -L3390:mydesktop.mycompany.net:3389 sshserver.mycompany.net". Start the native Windows Remote Desktop client and type localhost:3390 to remote into "mydesktop.mycompany.net"
• sometimes you may log into one machine from your local host, then login from there to another machine, and run an X application (eg. xterm, matlab) on the last machine to display on your local display. This is especially useful for running X applications on a department host from off campus but to which you have had to connect through another department host which is available for ssh login through the campus firewall. Essentially, you want to channel the X-window through a series of logins back to the host at which you are sitting. The best way to do this is to make use of the X11-forwarding feature of ssh. For unix/linux to unix/linux, force an X11-forwarding request with the '-X' option (capitalized x). ssh -X host.com
• X11-forwarding for through multiple hosts ssh -X hostA.com → ssh -X hostB.com → ssh -X hostC.com ensure the tunnel is working every step of the way by running something like xterm on host B then C. If this does not work the -Y may be needed. ssh -X -Y hostA.com → ssh -X -Y hostB.com → ssh -X -Y hostC.com
• with an SSH client that supports dynamic port forwarding (presenting to other programs a SOCKS or HTTP 'CONNECT' proxy interface), SSH can even be used for generally browsing the web through an encrypted proxy connection, using the SSH server as a proxy;
• with an SSH client that supports SSH exec requests (frequently embedded in other software, e.g. a network monitoring program), for automated remote monitoring and management of servers.
• using just a normal ssh login on a server, the SSH Filesystem can securely mount a directory on the server as a filesystem on the local computer.

Apple Terminal. ... Remote administration refers to any method of controlling a computer from a remote location. ... In software, headless refers to computer programs that use textual input/output to interact with users, instead of using graphics or graphical user interfaces (GUIs). ... In computing, the SSH File Transfer Protocol or SFTP is a network protocol that provides file transfer and manipulation functionality over any reliable data stream. ... This article is about the File Transfer Protocol standardised by the IETF. For other file transfer protocols, see File transfer protocol (disambiguation). ... Diagram of a public key infrastructure In cryptography, a public key infrastructure (PKI) is an arrangement that binds public keys with respective user identities by means of a certificate authority (CA). ... In cryptography, X.509 is an ITU-T standard for public key infrastructure (PKI). ... Certificate-based encryption is a system in which a certificate authority uses ID_based cryptography to produce a certificate. ... In computing, rsync is a computer program for Unix systems which synchronizes files and directories from one location to another while minimizing data transfer using delta encoding when appropriate. ... Secure Copy or SCP is a means of securely transferring computer files between a local and a remote host or between two remote hosts, using the Secure Shell (SSH) protocol. ... RCP may refer to: In computer science: Rich Client Platform, a software development platform helping software developers to rapidly build new Java applications RCP (chip), a co-processor chip designed by Silicon Graphics for use in the Nintendo 64 gaming system rcp (Unix), a command on the Unix operating systems... A Virtual Private Network, or VPN, is a private communications network usually used within a company, or by several different companies or organizations, communicating over a public network. ... Terminal Services is a component of Microsoft Windows (both server and client versions) that allows a user to access applications and data stored on a remote computer over a network. ... Virtual Network Computing (VNC) is a desktop sharing system which uses the RFB (Remote FrameBuffer) protocol to remotely control another computer. ... Look up Socks in Wiktionary, the free dictionary. ... HTTP (for HyperText Transfer Protocol) is the primary method used to convey information on the World Wide Web. ... In computer networks, a proxy server is a server (a computer system or an application program) which services the requests of its clients by forwarding requests to other servers. ... The term network monitoring describes the use of a system that constantly monitors a computer network for slow or failing systems and that notifies the network administrator in case of outages via email, pager or other alarms. ... SSHFS (Secure SHell FileSystem) is a file system for Linux capable of operating on files on a remote computer using just a secure shell login on the remote computer. ... See Filing system for this term as it is used in libraries and offices In computing, a file system is a method for storing and organizing computer files and the data they contain to make it easy to find and access them. ...

SSH architecture

Diagram of the SSH-2 binary packet.

The SSH-2 protocol has a clean internal architecture (defined in RFC 4251) with well-separated layers. These are: Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ...

• The transport layer (RFC 4253). This layer handles initial key exchange and server authentication and sets up encryption, compression and integrity verification. It exposes to the upper layer an interface for sending and receiving plaintext packets of up to 32,768 bytes each (more can be allowed by the implementation). The transport layer also arranges for key re-exchange, usually after 1 GB of data has been transferred or after 1 hour has passed, whichever is sooner.
• The user authentication layer (RFC 4252). This layer handles client authentication and provides a number of authentication methods. Authentication is client-driven, a fact commonly misunderstood by users; when one is prompted for a password, it may be the SSH client prompting, not the server. The server merely responds to client's authentication requests. Widely used user authentication methods include the following:
  • "password": a method for straightforward password authentication, including a facility allowing a password to be changed. This method is not implemented by all programs.
  • "publickey": a method for public key-based authentication, usually supporting at least DSA or RSA keypairs, with other implementations also supporting X.509 certificates.
  • "keyboard-interactive" (RFC 4256): a versatile method where the server sends one or more prompts to enter information and the client displays them and sends back responses keyed-in by the user. Used to provide one-time password authentication such as S/Key or SecurID. Used by some OpenSSH configurations when PAM is the underlying host authentication provider to effectively provide password authentication, sometimes leading to inability to log in with a client that supports just the plain "password" authentication method.
  • GSSAPI authentication methods which provide an extensible scheme to perform SSH authentication using external mechanisms such as Kerberos 5 or NTLM, providing single sign on capability to SSH sessions. These methods are usually implemented by commercial SSH implementations for use in organizations, though OpenSSH does have a working GSSAPI implementation.
• The connection layer (RFC 4254). This layer defines the concept of channels, channel requests and global requests using which SSH services are provided. A single SSH connection can host multiple channels simultaneously, each transferring data in both directions. Channel requests are used to relay out-of-band channel specific data, such as the changed size of a terminal window or the exit code of a server-side process. The SSH client requests a server-side port to be forwarded using a global request. Standard channel types include:
  • "shell" for terminal shells, SFTP and exec requests (including SCP transfers)
  • "direct-tcpip" for client-to-server forwarded connections
  • "forwarded-tcpip" for server-to-client forwarded connections

This open architecture provides considerable flexibility, allowing SSH to be used for a variety of purposes beyond secure shell. The functionality of the transport layer alone is comparable to TLS; the user authentication layer is highly extensible with custom authentication methods; and the connection layer provides the ability to multiplex many secondary sessions into a single SSH connection, a feature comparable to BEEP and not available in TLS. The Digital Signature Algorithm (DSA) is a United States Federal Government standard or FIPS for digital signatures. ... This article is about an algorithm for public-key encryption. ... In cryptography, X.509 is an ITU-T standard for public key infrastructure (PKI). ... The purpose of a one-time password (OTP) is to make it more difficult to gain unauthorized access to restricted resources, like a computer account. ... S/KEY is a one-time password system developed for Unix-like operating systems. ... RSA SecurID tokens SecurID is a mechanism developed by Security Dynamics and currently owned by RSA Security for authenticating a user to a network resource. ... Pluggable authentication modules or PAM are a mechanism to integrate multiple low-level authentication schemes into a high-level API, which allows for programs that rely on authentication to be written independently of the underlying authentication scheme. ... The Generic Security Services Application Program Interface (GSSAPI, also GSS-API) is, as its name suggests, an application programming interface for obtaining security services. ... Kerberos is the name of a computer network authentication protocol, which allows individuals communicating over a non-secure network to prove their identity to one another in a secure manner. ... NTLM (New Technology LAN Manager) is a Microsoft authentication protocol used with the SMB protocol. ... Single sign-on (SSO) is a specialized form of software authentication that enables a user to authenticate once and gain access to the resources of multiple software systems. ... Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL), are cryptographic protocols that provide secure communications on the Internet for such things as web browsing, e-mail, Internet faxing, instant messaging and other data transfers. ... In computer networking, BEEP (Blocks Extensible Exchange Protocol) is a framework for creating network application protocols. ... Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL), are cryptographic protocols that provide secure communications on the Internet for such things as web browsing, e-mail, Internet faxing, instant messaging and other data transfers. ...

Security cautions

Since SSH-1 has inherent design flaws which make it vulnerable to, e.g., man-in-the-middle attacks, it is now generally considered obsolete and should be avoided by explicitly disabling fallback to SSH-1. While most modern servers and clients support SSH-2, some organizations still use software with no support for SSH-2, and thus SSH-1 cannot always be avoided. It has been suggested that Mafia Fraud Attack be merged into this article or section. ...

In all versions of SSH, it is important to verify unknown public keys before accepting them as valid. Accepting an attacker's public key as a valid public key has the effect of disclosing the transmitted password and allowing man in the middle attacks.

As with any encrypted protocol, SSH can be considered a security risk by companies or governments who do not trust their users and wish to eavesdrop on their communications. Furthermore SSH has built in tunneling features which make it easier for users to achieve passage of large volumes of information or to establish an entry point for unauthorized inward access over a SSH link than with other protocols.

How SSH uses public-key cryptography (with analogy)

Main article: Public-key cryptography

First, a pair of cryptographic keys is generated. One is the private key, the other is the public key. As an analogy, they can be thought of as a matching private-key and a public padlock. The public padlock is what is installed on the remote machine and is used by ssh to authenticate users which use the matching private key. As a user of the system, you don’t care who can see or copy the padlock (ie the public key), since only the secret private key fits it. The private key is the part you keep secret inside a secure box that can only be opened with the correct passphrase. When the user wants to access a remote system, he opens the secure box with his passphrase, and uses the private-key to authenticate him with the padlock on the remote computer. Neither the passphrase nor the private key leave the user's machine. However, the user still needs to trust the local machine not to scrape his passphrase or copy his private-key while it's out of the secure box. A big random number is used to make a public-key pair. ... A key is a piece of information that controls the operation of a cryptography algorithm. ... Analogy is both the cognitive process of transferring information from a particular subject (the analogue or source) to another particular subject (the target), and a linguistic expression corresponding to such a process. ... Padlock A modern padlock. ... A passphrase is a sequence of words or other text used to control access to a computer system, program or data. ...

See also

Wikibooks has a book on the topic of

Internet Technologies/SSH

• Comparison of SSH clients
• AbsoluteTelnet - A tabbed Serial, Dialup, SSH, Telnet, and SFTP client
• VNC can be tunneled through SSH to securely access a remote machine that is behind a firewall
• Cygwin allows many Linux/BSD programs to run on Windows, including the OpenSSH client and server
• Corkscrew - a tool that enables a user to run SSH over HTTPS proxy servers
• Transport Layer Security
• Ident
• WinSCP
• PuTTY - Free Serial, Telnet and SSH client
• TeraTerm - Free Serial, Telnet and SSH client
• SSHFS - Secure protocol to share files over SSH
• Dropbear - Free SSH-2 client and server software useful for embedded systems

Image File history File links Wikibooks-logo-en. ... Wikibooks logo Wikibooks, previously called Wikimedia Free Textbook Project and Wikimedia-Textbooks, is a wiki for the creation of books. ... Image File history File links This is a lossless scalable vector image. ... This article or section is incomplete and may require expansion and/or cleanup. ... AbsoluteTelnet is a software terminal client for Windows that implements Telnet, SSH 1 and 2, SFTP, TAPI Dialup and direct COM port connections. ... For the packet switched network, see Telenet. ... SFTP may refer to: Relating to internet file transfer: SSH file transfer protocol, a network protocol designed by the IETF to provide secure file transfer and manipulation facilities over the secure shell (SSH) protocol. ... Virtual Network Computing (VNC) is a desktop sharing system which uses the RFB (Remote FrameBuffer) protocol to remotely control another computer. ... Cygwin (pronounced ) is a collection of free software tools originally developed by Cygnus Solutions to allow various versions of Microsoft Windows to act similar to a Unix system. ... Corkscrew enables you to run SSH connections over most HTTPS proxy servers. ... https is a URI scheme used to indicate a secure HTTP connection. ... In computer networks, a proxy server is a server (a computer system or an application program) which services the requests of its clients by forwarding requests to other servers. ... Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL), are cryptographic protocols that provide secure communications on the Internet for such things as web browsing, e-mail, Internet faxing, instant messaging and other data transfers. ... This article is about the Internet protocol. ... WinSCP (Windows Secure copy) is an open source SCP, SFTP and FTP client for Microsoft Windows. ... PuTTY is a free software SSH, Telnet, rlogin, and raw TCP client. ... For the packet switched network, see Telenet. ... Tera Term is open source free software terminal emulator (communication program) for MS-Windows. ... For the packet switched network, see Telenet. ... SSHFS (Secure SHell FileSystem) is a file system for Linux (and other operating systems with a FUSE implementation, such as Mac OS X) capable of operating on files on a remote computer using just a secure shell login on the remote computer. ... Dropbear is a software package written by Matt Johnston that provides a Secure Shell-compatible server and client. ...

References

1. ^ http://www.snailbook.com/faq/ssh-1-vs-2.auto.html
2. ^ Nicholas Rosasco and David Larochelle. How and Why More Secure Technologies Succeed in Legacy Markets: Lessons from the Success of SSH. Quoting Barrett and Silverman, SSH, the Secure Shell: The Definitive Guide, O'Reilly & Associates (2001). Dept. of Computer Science, Univ. of Virginia. Retrieved on 2006-05-19.
3. ^ https://www.kb.cert.org/vuls/id/MIMG-6L4LBL

• Daniel J. Barrett, Richard E. Silverman, and Robert G. Byrnes — SSH: The Secure Shell (The Definitive Guide), O'Reilly 2005 (2^nd edition). ISBN 0-596-00895-3 [1].
• Michael Stahnke — Pro OpenSSH, Apress 2005 ISBN 1-59059-476-2 [2].
• Kurt Seifried, What's in a Name?, February 14, 2001, [3].
• "ANNOUNCEMENT: Ssh (Secure Shell) Remote Login Program", comp.security.unix, 12 July 1995.  Original announcement of Ssh by Tatu Ylönen

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 139th day of the year (140th in leap years) in the Gregorian calendar. ... is the 45th day of the year in the Gregorian calendar. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ... is the 193rd day of the year (194th in leap years) in the Gregorian calendar. ... Year 1995 (MCMXCV) was a common year starting on Sunday (link will display full 1995 Gregorian calendar). ...

External links

The external links in this article may not comply with Wikipedia's content policies. Please improve this article by removing excessive or inappropriate external links.

• Old homepage for IETF 'secsh' working group, which has concluded (for SSH-2)
• RFC 4251 (SSH-2 architecture); other documents documenting other aspects of the protocol are referenced from here
• http://www.openssh.org/ - Home to the most widely used SSH implementation
• OpenSSH Project History and Credits - on openssh.org
• SSH Communications
• SSH: Introduction to Secure SHell on www.math-linux.com
• OpenSSH key management, Part 1 - Understanding RSA/DSA authentication - article on IBM.com
• SSH Tutorial - Including examples of tar-over-ssh and port forwarding tricks
• Using SSH - article by Ka Chun Leung on linux.ie about SSH
• A short guide to SSH port forwarding - article on bitvise.com
• SSH Tutorial for Linux - article on suso.org
• SSH tricks - on polishlinux.org
• X-window Forwarding Through Multiple Login Sessions
• JavaScript based web SSH service
• SSH - article on WindowsSecurity.com about SSH
• A free, native implementation of an SSH server for Windows NT, XP, Vista?
• HOWTO: Set up a Windows SSH Server for VNC Tunneling
• Chapter 4. Using Cygwin/X - from Cygwin/X User's Guide
• How to install OpenSSH sshd server and sftp server on a Windows 2000 or Windows XP
• MindTerm Signed Java SSH Client - Useful as primary client or when on machines without SSH clients.

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