encrypting netcat 1.10

[Pawel Krawczyk]

I've added a trivial RC4 encryption support for popular Netcat 1.10.
It works like this:

        $ ./nc -l -k dupa-20 -p 12345 >received.txt &
        $ ./nc -vv -k dupa-20 localhost 12345 <README

Where "-k" argument is the key. It's trivial and doesn't support
*any* data integrity checking. But it's fast and suitable for bulk
data transfers, when performance is the primary aim.

-- 
Paweł Krawczyk *** home: <http://ceti.pl/~kravietz/>
security: <http://ipsec.pl/>  *** fidonet: 2:486/23