From ALICE Documentation
It is possible to setup ssh using keys only.
Setup Linux ssh for key based login
Setup PuTTY to use key based login
Before we can use key based login we first need to create a private/public key set. THis is doen by the program puttygen. Open this program:
and hit the 'Generate'key. You will have to move your mouse around as this will help randomness in the creation of the key pair. Once the keys have been created you need to save each key in its own file.
Make sure to use sensible file names for the two key files. The private key is automatically appended with the .ppk extension, while the public key does not need an extension.
Now we must make PuTTY aware of the private key. Go to SSH - AUTH and use the Browse button to select the file in whuch you have previously saved the private key (usually extenstion .ppk).