Generate SSH key to login automatically with putty

Use puttygen.exe to make a private key.
Make .ssh/authorized_keys file and add text ” ssh-rsa ” with spaces,
following the public key from the private key file on one line.
Assign rw permissions only for the owner. $ chmod 600 ~/.ssh/authorized_keys.
Configure putty to use the private key when connecting (Connection -> SSH -> Auth).

More detailed instructions: http://www.tonido.com/blog/index.php/2009/02/20/ssh-without-password-using-putty/