Jeffrey Jabson

AUTOMT

Definition: A Finite State Automaton is a graph determined with a 5-tuple where V is a finite set of vertices (states), E is a finite set of edges, is the labeling function, is the set of initial states, and is the set of terminal states. So every SA is also a finite state automaton by taking I=T=V. We extend to a labeling function where P is the set of all finite paths in the natural way: if is a path in than . As before we consider two functions as the source and the target of an edge. For a finite path we will call s(e₁) the source of p and write s(p) and t(e_k) will be the target of p and we will write t(p).

A finite state automaton is called deterministic if for every vertex the out-coming edges are labeled distinctly.

In the case of a deterministic finite state automaton we will use the following notations: Let p be a path with v=s(p), w=t(p) and . We will write vx=w and if there is no path starting at v with label x, we will write vx = 0.

A finite-state automaton is a device that can be in one of a finite number of states . In certain conditions, it can switch to another state. This is called a transition . When the automaton starts working (when it is switched on), it can be in one of its initial states. There is also another important subset of states of the automaton: the final states. If the automaton is in a final state when it stops working, it is said to accept its input. The input is a sequence of symbols. The interpretation of the symbols depends on the application; they usually represent events, or can be interpreted as "the event that a particular data became available". The symbols must come from a finite set of symbols, called the alphabet . If a particular symbol in a particular state triggers a transition from that state to another one, that transition is labeled with that symbol. The labels of transitions can contain one particular symbol that is not in the alphabet. A transition is labeled with E (not present in the alphabet) if it can be traversed with no input symbol.

SEMINAR ON NETWORK SECURITY ( 10-12-2002 at AMACC Pasig ) By: Mr. Richard Chan

Details/Summary:

Security Threats [ Hacking Tools ]

• probes, denial of service, spoofing, password cracking, viruses.

Computer Crime & Security Survey – states that every year, the education sector, government, and top 100 corporations are greatly affected and encounter network security problems. [ www.gocsi.com ]

Potential Risks ( from a hack attack )

• monetary loss
• theft of confidential data
• deletion of data
• loss of productivity
• loss of consumer confidence
• loss of reputation

Security Solutions ( Key Points ):

• address security from all areas of the enterprise
• security cannot be improved solely by technology
• people and processes are equally as important as technology
• security is a business problem, not an I.T. problem
• security is insurance, it cannot be sure

• Network security really poses grave consequences and troubles in our community, specially if government databases are the ones that get bogged down by unscrupulous and evil computer technology users. It makes the long, hard hours of work by certain individuals go to waste and lessens productivity. But I still believe that a large percentage of the "hackers" are the ones who created the systems themselves. Like for example computer viruses -- those who create and sell computer virus software are the ones, believe it or not, who create computer viruses that cause at times annoyance, but in some cases great damage to our computer systems. Of course the logic or motive of such deeds is to have profit ( $$$ ) !

• The real fight against network security is for the government and business sectors around the world to solve. World superpowers like the United States of America, some nations of the European Union and as well as Asia are at risk for they hold and keep vital information and secrets within their computer systems, and with the sudden increase of global terrorism they must not get caught flat-footed or else the results would be disastrous.

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