Our Definition of  "Secure"

    An important thing to realize is what it means to be "secure."  This is not meant to be a course in security, but a few things do need to be explained and understood.  These are outlined below.

    First, and foremost, nothing is absolutely secure.  Absolutely secure would mean that no one would have access to it in any shape or form (and that doesn't sound very useful to me.)  Security deals with everything from people not handing out their passwords like it was candy on Halloween to people having physical access to the computer to hackers trying to infiltrate (or bring down) a foreign system.

    Because of this, we limit our definition of security to just the ability of hackers to view the login names and their associated passwords. 

    So, in programs such as telnet (and even worse, ftp), we say that these are very insecure since they allow anyone to sniff the IP packets and determine the information based on a clear-cut formula.  Which means that even if you had two "totally" secure machines, they couldn't talk to each other over the network without others able to listen in easily to the packets.

    Thus Secure Shell was made, so that two "totally" secure machines could relatively be secure even when talking to each other.

    These "totally" secure machines don't really exist, but the Secure Shell does not bother with the endpoint's security.  It's main purpose to make connections BETWEEN machines secure.  It should be noted that even when we say "secure" here, it is still not absolutely secure, but due to the way encryption algorithms work, it is highly doubtful that anyone could crack the code in a timely manner (for more detailed understanding of how encryption works, one would need to understand complexity classes.  See here for the theory, and here for more information on encryption.)

    Therefore, we will define "secure", with regards to network communication, as the lack of ease that hackers or other malcontents could listen in to IP packets going over the network and understand the actual information within the packets.