What Is SSH (Secure Shell) & How Does It Work

What Is SSH

SSH (secure shell), a remote administration protocol, allows you to control and modify your servers over the Internet. The SSH is a cryptographic network protocol, which enables you to operate network services safely even through an unsecured network.

It is because that the protocol will create a secure connection to the shell on another computer.

This SSH protocol was built for replacing the unencrypted Telnet. Thanks to cryptographic techniques, SSH can ensure that all communications to and from the remote server happen in an encrypted manner. Besides, it offers a mechanism for authenticating a remote user, transferring inputs from the SSH client to host, as well as relaying the output back to the client.

Read here, you can know the SSH meaning clearly. If you would like to obtain more information about SSH secure shell, please keep reading this post of MiniTool.

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The Application of SSH

SSH protocols are commonly used in remote command-line, login, as well as remote command execution. Besides, any network service can be protected with SSH. The SSH secure shell enables 2 computers build a safe connection within a potentially unsafe network. In this way, third-parties are unable to access the data stream (that can cause data leak). SO, the data streams will not be read or operated by others.

In addition to the encrypted connection, SSH can make sure that the connection is established between the designated computers. If so, only authorized participants can contact each other.

As a network protocol, SSH can be used in a wide range. For instance, any Linux or MacOS user can enter his remote server directly from the terminal window via SSH. For Windows users, they can take advantage of SSH clients like Putty. In a word, SSH can run on all operating systems. Besides, SSH has other applications as listed in the following.

• Manage servers that cannot be accessed locally
• Protect the transmission of files
• Secure the creation of backups
• Connect 2 computers with end-to-end encryption
• Maintain remotely from other computers

If you would like to set up SSH client, you can refer to this guide: How to Set up SSH Client and Servers on Windows 10 [Full Guide]

How Does SSH Work

As you know, SSH protocol offers a safe channel over an unsecure network through a client-server architecture, which can connect an SSH client application. What’s more, the connection is encrypted, so you are required to authenticate if you want to access the data stream.

How to do? The first step is to make the SSH client and server authenticate themselves to one another. Generally speaking, the server will send a certificate to the client to prove that it is the right server. When the client knows the correct certificate, no third-parties can make contacts to the relevant server.

After that, the client will identify itself too. Here, you can set a password to identify the client. As the password or the encrypted hash value is saved on the server, you have to enter the password each time you log onto the different server during the same session.

Then, the two communication participants will build an encrypted connection. You need to create a key at first, but you have to keep in mind that the key will become invalid when the session ends. Besides, the key utilized for symmetric encryption is only valid with this one session.

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SSH VS OpenSSH

One more thing you need to know about SSH is that the existence of OpenSSH. What is OpenSSH? When talking about OpenSSH, it is inevitable to discuss of the development of SSH.

SSH secure shell was developed in 1995 and used as an open source project. In the same year, the developer of secure shell found a firm who developed the protocol further. Given to that fact, the initially opened project got more and more into a proprietary software.

However, this action was against by the network community. And the community developed an open split on the basis of SSH-1 protocol – OpenSSH. As the SSH community security is also going on cooperating with secure shell, the 2 protocols exist side by side now.

On the aspects of functionality and scope, the two protocols are rather similar. The main difference is the cost and the support. So, you can choose one based on your demand.

What is SSH? Now, you may have an overall understanding of it.