There seem to be many win32 shareware programs for creating Rijndael symmetric keys, but is there a GNU way to do this in linux? What would the simplest approach be? The needed package(s)?
Thanks

Wouldn't any random junk of the appropriate size work? But, you can encrypt with a randomly generated salt and a passphrase: You'll be prompted for the passphrase. To decrypt, use

I am afraid this is my own ignorance of the whole key concept coming through. I am interested in using the fwknop single-packet authorization method of knocking into my firewall. The only windows client for this software requires the use of symmetric Rijndael keys. I presume that I need to put the key (that I create somehow) into the configuration file in the server, and then use the same (symmetric) key in the client when it tries to authenticate. I have an email into the author to see if he can point me at a tutorial on how to configure the SW. I suspected that I might be missing some pretty elementary steps on how to create the keys -- maybe I still am. Anyone point me at something that would educate me a little bit better about how to create a key for this sort of thing? Or is there no need to "create" a key at all?

The author replied to me. Evidently I am making more of things than I should. The symmetric "key" is nothing more than a password that is shared between server and client. No wonder I had so much trouble finding anything about this type of key...