What does security mean?
Human beings understand well what security means in real world. First
an foremost it means one's physical security from any harm. It further
means security of one's property, so it does not get stolen or
damaged.
In a broader sense, we can enumerate security requirements in real
world in the following manner:
- One's physical security from any harm (e.g., being hurt, feeling scared)
- Security of one's property from theft, damage, misuse (e.g., what
if someone uses my house to throw water balloons on others) or trespassing
- Verifiable identities of all persons that matter (bank tellers,
police officers, friends)
- Ability to minimize or eliminate unwanted interactions
(e.g., solicitation phone calls, begging, asking for petition signatures)
- Ability to freely move and engage in activities (e.g., visit a
favorite park or restaurant, take a fast road into the city)
Notice that some of these requirements relate to one's safety and
others relate to convenience, i.e. we both want to be safe and to
go about our business with minimal distraction from others.
In computing and networking one can find the similar cobmination
of security requirements that blend the need for safety with the need
for uninterupted operation. Making a parallel with physical security
requirements, in the Internet I may want (this is not a comprehensive list):
- Physical security of my machine (my machine will not be
broken into)
- Security of my data from theft, damage
- My machine will not be misused to harm others (e.g., DDoS, phishing)
- My machine, its programs and any physical devices it may control
will behave as intended
- I will be able to verify identity of remote machines/institutions,
origin of remote data
- I will not waste time nor machine/network resources on unwanted
tasks (spam, phishing, DDoS)
- I will be able to communicate to any chosen server at any time,
barring accidental networking/server failures
Many of you have heard about computer security (e.g., security from
intrusion, viruses, worms, etc.) How does it relate to network
security? Computer security aims to protect a single machine and
data residing on it. Networking goal is to enable communication
between any pair of machines, in any scenario. Thus the goal of
network security is to protect this communication and all
participants. The focus of network security is thus on threats that
require network access to be perpetrated.
Another issue that often arises is whether security means robustness
(e.g., no one can break into my computer), or fault-tolerance (e.g.,
fast detection of intrusions and patching). In real world security is
achieved by combining techniques that achieve robustness and
fault-tolerance. Known and distinct threats should be prevented, while
new and stealthy threats should be quickly detected and handled.
Questions & Comments: Prof. Mirkovic at USC-ISI (sunshine at isi.edu)
