You can create your public and private keys on your desktop computer using putty and puttyGen and then login to your servers without entering username and password each time you login.
To do so follow these easy steps.
On Client side:
1. open PuttyGen and click Generate Button, to get your public key in the upper text box, copy it as you well need it later.
2. Now click ‘Save public key’ button and ‘Save private key’ button to save these keys in files say public.ppk and private.ppk respectively.
On Servr side:
1. Login to server using putty and goto home folder.
2. create .ssh folder structure by using command ssh-keygen.
3. now cd to .ssh and type nano authorized_keys and paste the public key you copied in step 1 (Client side). save and exit.
Connect from client without requiring passwords:
1. open putty and type username@server in the host box.
2. In Connectoin ->ssh click Auth and browse for the private key you saved in step 2 above (Client side).
3. Save the connection by putting a name in Saved session box under Session tab. and click save button.
4. Click the name of the save session and click open button.
That’s all, you are connected.