In order to use SecureCRT to connect to your server, you must first generate an SSH public key. With SecureCRT, you can use the “Public-Key Assistant” to do this. In the Tools menu click the Create Public Key entry. See this article for more information.

On the server side, you will need to copy the public key to your user’s ~/.ssh/authorized_keys file. This tutorial walks you through the process:

• How To Set Up SSH Keys