Design goals

The design goals for the encryption option are:

1. Possible to start/stop encryption separately in each direction
2. Possible to change the session key at any time, without closing the connection.
3. All data should be encrypted, i.e. both the user data and option code sequences.
4. Must be easy to extend with new cipher types and modes of operation.
5. Must use the standard Telnet option code framework and be a feature in the Telnet application layer.