3.8.3.20 -hostkey: manually specify an expected host key
This option overrides PuTTY's normal SSH host key caching policy by telling it exactly what host key to expect, which can be useful if the normal automatic host key store in the Registry is unavailable. The argument to this option should be either a host key fingerprint, or an SSH-2 public key blob. See section 4.20.2 for more information.
You can specify this option more than once if you want to configure more than one key to be accepted.