You can't copyright an algorithm. IDEA is patented in certain countries
with arse backward legal systems. Before you do a lot of work have a look
at ssh and the algorithms it uses. Some of those are believed both strong
and patent free.
> Importing into the US is legal, I think. I could put up stuff on my FTP
> space.
>From .de you are better uploading it into another EEC site (EEC single
market) as germany has some but not US scale export rules on crypto.
ALan