On Windows client, we need:
- PuTTY
- PuTTYgen
- Pageant
Use PuTTYgen to make key pair, save private key to file and copy public key to clipboard. Add key to Pageant.
On Unix remote, edit ~/.ssh/authorized_keys and add public key from Windows clipboard (one-line).
Use PuTTY to login to remote. WinSCP also uses Pageant when possible.