The Host Keys panel allows you to configure options related to host key management.
Host keys are used to prove the server's identity, and assure you that the server is not being spoofed (either by a man-in-the-middle attack or by completely replacing it on the network). See section 2.2 for a basic introduction to host keys.
Much of this panel is only relevant to SSH protocol version 2; SSH-1 only supports one type of host key.