For webmasters who have paid much attention to the website security, the term of SSH may not be a strange thing. As researched online, the majority of website owners have heard about it, and some of them even know this is a security protocol. However, many people have no idea what benefits this technology can bring to their websites, and how can SSH achieve the protection purpose. In this case, we’d like to make a detailed introduction concerning about what is Secure Shell (SSH).
What is SSH
In fact, the full name of SSH is Secure Shell. This technology is a network protocol used to guarantee a secure and risk-free environment for data transfer and remote execution between two connected computers, eliminating the possibilities of information leaking effectively during the remote management. Initially, SSH is a program of UNIX system, but now it can be used for many platforms including Linux, AIX, Irix, Solaris, Digital UNIX, and many more. To be honest, the utilization of SSH can fix many loopholes of the Internet perfectly.
The Benefits of SSH
Frankly speaking, the traditional remote protocols including FTP, Pop, and Telnet are not safe. This is because they make use of the plain text to transfer the keys and passwords on the web, allowing hackers to capture the sensitive information easily during the transferring process. SSH, however, is developed as a replacement of these insecure protocols to encrypt the transferred date over the dangerous network.
In fact, during the process when you transfer data to your server, the man-in-the-middle can do something hard to you easily. He can act as the real server to receive your data, and then act as you to send the bad data to your server. Once this happens, you may encounter many serious security problems. SSH, however, has a solid and strict authentication system, and encrypt the data in the most secure manner, helping you avoid this kind of attack easily.
The authentication system is used to help systems make sure that you are the intended and actual client for data receiving and transferring, leaving anyone else no opportunity to pretend as you. At present, SSH has included many authentication methods, including password authentication, public key authentication, NTLM, Kerbero, and many more. Even, this system is constantly refined, integrating many other advanced methods for authentication.
Super-Fast Data Transfer
Generally, the transfer speed of multiple small data is much slower than that of a large file. Therefore, if you want to transfer a large amount of data or information, the process may take you a long time. However, SSH can transfer with the best efficiency for it compresses your data automatically into a single one, shortening the time needed for transfer greatly.
The Authentication Levels of SSH
Unlike SSL that focuses on encryption, SSH views authentication greatly. After all, a safe and advanced authentication system can guarantee the smooth data transfer effectively.
In fact, there are two levels of authentication offered by SSH. The first level is based on the username and password, and the second one is based on a pair of secret keys.
To be honest, the first level is not secure enough. You can make some remote executions once you have the username and the password needed. Although the transferred data is encrypted during the transferring process, you may still encounter the security issue as the server you are connecting may be pretended by a hacker. In this case, you’d better resort to the second level making use of secret keys created by yourself. In the following, we’d like to introduce the steps in general.
- You create a pair of keys for both public and private, and put the public key on the server you want to connect.
- When you connect the server, SSH sends a request firstly for authentication using your public key.
- Then, the server figures out whether the public key received can match the one that is located previously.
- If two keys are the same, the server notifies to SSH with an encrypted challenge.
- SSH sends you private key to server for decryption.
This authentication level is undoubtedly more secure and safe, but it may need a longer time for login.