![]() ![]() Perhaps the most straightforward is to add your public key to the metadata for your Google Cloud account. If your Ubuntu system is hosted by Google Cloud, for example as a Compute Engine instance, there are a number of different ways to gain SSH access to the server using key-based authentication. 1.10 Installing the Public Key for a Google Cloud Instance To install the public key on the remote server use the steps covered in the earlier section on using SSH within PowerShell on Windows 10. The private key can be used with PuTTY as outlined in the previous section. Once the keys have been generated, save the files to suitable locations using the Save public key and Save private key buttons. Move the mouse pointer around to generate random data as instructed, then enter an optional passphrase with which to encrypt the private key. Launch PuTTY from the Start menu and enter the IP address or host name of the remote server into the main screen before selecting the Connection -> SSH -> Auth category in the left-hand panel as highlighted in Figure 18-3: ssh folder but give it a different name to differentiate it from the original key file. For consistency, save the key file to the. Once the private key has been imported, save it as a PuTTY key file by clicking on the Save Private Key button. When prompted, enter the passphrase originally used to encrypt the file. Once located, select the file and load it into PuttyGen. ssh folder (note that it may be necessary to change the file type filter to All Files (*.*) in order for the key file to be visible). Once launched, click on the Load button located in the Actions section and navigate to the private key file previously copied to the. The remainder of this chapter will outline these steps in greater detail for Linux, macOS and Windows-based client operating systems. Disable password-based authentication on the server.There are four steps to setting up key-based SSH authentication which can be summarized as follows: As an added layer of protection, therefore, the private key may also be encrypted and protected by a password which must be entered each time a connection is established to the server. It is important to protect the private key, since ownership of the key will allow anyone to log into the remote system. In the case of SSH key-based authentication, the private key is held by the host on which the SSH client is located while the corresponding public key resides on the system on which the SSH server is running. In a public key encryption system, the public key is used to encrypt data that can only be decrypted by the owner of the private key. The concept of public key encryption was devised in 1975 by Whitfield Diffie and Martin Hellman and is based on the concept of using a pair of keys, one private and one public. SSH key-based authentication makes use of asymmetric public key encryption to add an extra layer of security to remote system access. Buy the full book now in eBook ($14.99) or Print ($36.99) format. You are reading a sample chapter from Ubuntu 20.04 Essentials. This weakness can be addressed by implementing SSH key-based authentication. If a malicious party is able to identify the password for an account (either through guess work, subterfuge or a brute force attack) the system becomes vulnerable. The inherent weakness in a basic SSH implementation is that it depends entirely on the strength of the passwords assigned to the accounts on the system. All of the communications between client and server, including the password entered to gain access, are encrypted to prevent outside parties from intercepting the data. A user might, for example, use an SSH client running on a Linux, Windows or macOS system to connect to the SSH server running on an Ubuntu system to gain access to a shell command-line prompt or to perform file transfers. As will be covered in “Ubuntu Remote Desktop Access with Vino”, SSH can also be used to provide a secure tunnel through which remote access to the GNOME desktop can be achieved over a network connection.Ī basic SSH configuration consists of a client (used on the computer establishing the connection) and a server (running on the system to which the connection is to be established). SSH is designed to allow secure remote access to systems for the purposes of gaining shell access and transferring files and data. This chapter will outline the steps to increase the security of an Ubuntu system by implementing key-based SSH authentication. ![]() This level of security is far from adequate and should be upgraded to SSH keybased authentication as soon as possible. When installed, SSH provides password protected and encrypted access to the system for the root account and any other users added during the installation phase. When an Ubuntu system is first installed, it is not configured by default to allow remote commandline access via Secure Shell (SSH) connections. ![]()
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