How to use SSH Keys With PuTTY On Windows and Connect Linux Server

The SSH key pair establishes trust between the client and server, thereby removing the need for a password during authentication.

The PuTTY SSH client for Microsoft Windows does not share the same key format as the OpenSSH client. Therefore, it is necessary to create a new SSH public and private key using the PuTTYgen tool or convert an existing OpenSSH private key.


1) Install PuTTY And PuTTYgen

Download from

2) Open PuTTYgen in the Windows 

Create New Public And Private Keys

  • Under Parameters, increase the Number of bits in a generated key: to a minimum value of 2048.
  • Under Actions / Generate a public/private key pair, click Generate.
  • You will be instructed to move the mouse cursor around within the PuTTY Key Generator window as a randomizer to generate the private key.
  • Once the key information appears, click Save private key under Actions / Save the generated key.
  • Also Save the public key for future reference
  • Save the private key to the desktop as id_rsa.ppk.(or any name what you want)
  • The box(Highlighted in yellow) under Key / Public key for pasting into OpenSSH authorized_keys file: contains the public key.

3) Copy the public key into the authorized_keys file on Linux server.

On Linux server connect with a respective user which is required.

vi ~/.ssh/authorized_keys
Paste the public key into the authorized_keys file.

ssh-rsa AAAAB3NzaC1yc2EAAAABJQAAAQEAgskJlM8S5xebUvICRGkuD7HhEPpGTTdWZ+KbezdMwTchtnHvK/VsWluAw6VcBsMG8eccnlwSTQi07oGj78txEJQjA9cOILBnb2ux7fF17prP0RAgcISEg7z+Ltq0x0Z28UvAYAOO5wX5Tx7CXhIoh7he+BaQkp4jRXehjsggQjFlIwfhacfrBxQdpO7R/HUpsSiLlcBnDrysftIZcysUuFlugAIFYHh3U9IPOQOeQ/DBRxo66MMqba4KPG1gl5u351KrYsPpJ7Mu/9rPpmz7EXFQPeL3nP+l5a+DZXD+aZDaXuPvuFjuqUvQiOdOJfrpT4Zo6Ln/3qlDfCGvLRWBYQ== rsa-key-20210831

Save the file and close 

Adjust the permissions of the authorized_keys file 
chmod 600 ~/.ssh/authorized_keys

4) Connect To Server With Private Key

Open Putty

  • Enter the remote server Host Name or IP address under Session(Where the authorized key files were updated/added).
  • Navigate to Connection > SSH > Auth.
  • Click Browse... under Authentication parameters / Private key file for authentication.
  • Locate the Himanshu.ppk(as I gave that name) private key and click Open.
  • Now you will be logged into the remote server with key pair authentication.

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