This article provides steps for generating RSA keys by using PuTTYgen on Windows for secure SSH authentication with OpenSSH.
One effective way of securing SSH access to your Cloud Server is to use a public/private key pair. This means that a public key is placed on the server and a private key is placed on your local workstation. Using a key pair makes it impossible for someone to log in by using just a password, as long as you set up SSH to deny password-based authentication.
In Windows, use PuTTYgen to generate our public and private keys.
From the Public key for pasting into OpenSSH authorized_keys file field at the top of the window, copy all the text (starting with ssh-rsa) to your clipboard by pressing Ctrl-C.
You need the this key available on your clipboard to paste either into the public key tool in the Control Panel or directly into the authorized keys on your cloud server.
You can use the RSA key pair in the following ways:
When you create a cloud server, you can add a new public key or assign an existing public key.
To add a new public key, perform the following actions:
To make use of your newly generated RSA key pair, you must tell PuTTY to use it when connecting to your Cloud Server.
The key and its associated text (the ssh-rsa identified at the start and the comment at the end) should all be on one line in the file. If the text is word-wrapped onto multiple lines an error might occur when connecting.
chmod 600 ~/.ssh/authorized_keys
To make PuTTY use the key every time that you connect to your Cloud Server, save the configuration by going to the Session page and saving the session.
After you save your session, your key is loaded automatically whe you connect to your Cloud Server.
Opting for a key-based authentication to your SSH server is beneficial in many ways. By eliminating the possibility of SSH brute-force attacks targeted towards your Cloud Server, the chances of it being compromised are decreased by an order of magnitude.
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