• 14/10/2010 -- Stuxnet as a Cold War Weapon and New Generation Armament (0)

• 16/01/2012 -- Cyber Security Conference 12 (0)

When I tried to run "ifconfig wlan0 up", I got "no such file or directory". After that i realized that that is different bug than known "Network Disabled" bug. Anyway i found a solution that worked for me.

• Enter http://linuxwireless.org/en/users/Download/stable/
• Find correct kernel driver
• sudo apt-get install build-essential
• wget http://intellinuxwireless.org/iwlwifi/downloads/iwlwifi-5000-ucode-5.4.A.11.tar.gz
• tar -xzvf iwlwifi*
• sudo cp iwlwifi-5000-ucode-5.4.A.11/iwlwifi-5000-1.ucode /lib/firmware
• bunzip2 compat-wireless-old
• tar xf compat-wireless-old
• cd compat-wireless*old*
• make
• sudo make install
• sudo make unload
• sudo make load

Reboot your system. That solution should fix your Wireless and Network Disabled problem.

it is when you know the time has come, when you feel the next minute will just carry the pain inside, then there is nothing left to be scared of and nothing to lose. That is when there is no greater power then the power of goodbye. Even though you know it will hurt you so much, and so deep, you know that it is the only way to get out from the vicious circle you are round up with. You just have to say goodbye…
That is the only way to break the spell…That is the only way to set free your soul again…That is a lesson to be learned…Freedom comes only when you learn to let go…

A teacher takes responsibility of your growth
A Guru makes you responsible for your growth

A teacher gives you things you do not have and require
A Guru takes away things you have and do not require

A teacher answers your questions
A Guru questions your answers 

A teacher helps you get out of the maze
A Guru destroys the maze 

A teacher requires obedience and discipline from the pupil
A Guru requires trust and humility from the pupil 

A teacher clothes you and prepares you for the outer journey
A Guru strips you naked and prepares you for the inner journey 

A teacher is a guide on the path
A Guru is a pointer to the way 

A teacher sends you on the road to success
A Guru sends you on the road to freedom 

A teacher explains the world and its nature to you
A Guru explains yourself and your nature to you 

A teacher makes you understand how to move about in the world
A Guru shows you where you stand in relation to the world 

A teacher gives you knowledge and boosts your ego
A Guru takes away your knowledge and punctures your ego

A teacher instructs you
A Guru constructs you 

A teacher sharpens your mind
A Guru opens your mind

A teacher shows you the way to prosperity
A Guru shows you the way to posterity 

A teacher reaches your mind
A Guru touches your spirit

A teacher gives you knowledge
A Guru makes you wise

A teacher gives you maturity
A Guru returns you to innocence 

A teacher instructs you on how to solve problems
A Guru shows you how to resolve issues 

A teacher is a systematic thinker
A Guru is a lateral thinker 

A teacher will punish you with a stick
A Guru will punish you with compassion 

A teacher is to pupil what a father is to son
A Guru is to pupil what mother is to her child 

A teacher leads you by the hand
A Guru leads you by example 

When a teacher finishes with you, you celebrate
When a Guru finishes with you, life celebrates 

When the course is over you are thankful to the teacher
When the discourse is over you are grateful to the Guru 

Let us honor both, the teachers and the Guru in our life.

    * A mythical story about me
    * A demo for digital investigation and some brainstorming activities for an assassin plan
    * A demo for web application security includes port scanning, information gathering from http, https ports, banner grabbing, etc
    * Detailed information about OWASP and OWASP Turkey
    * Definition of Cyber World Concept
    * Examined the security necessity on cyber world
    * Defined cyber security concept
    * Talked about Terrorism, cyber-terrorism, cyber wars
    * Gave a functional approach to Terrorism
    * Highlighted the importance of web application security, threats, attack vectors, DoS, Buffer overflows, Injections,etc.
    * Generated a wide and deep multidisciplinary cyber security perspective
    * Finally, we talked about how we can prepare ourselves for future threats a little.

Actually, I was surprised by both seminars. I was planning to talk around 50 minutes however people were interested in the topic more than I could guess. So, I had to talk around 2-3 hours which I really enjoyed.

I think both seminars gave a new perspective about the future definitions of security and risk to listeners. I will write about these topics on this site later.

On the other hand, I will be in a IPTV show to talk about cyber terrorism with two lawyers soon, but before that, on the 29 April 2010, I will be in Yeditepe University, Istanbul to talk about cyber-terrorism for the Information Technologies Law Organization.

Besides that, I have a almost new job somewhere in Europe. I will also tell the details about that.

I will be in Istanbul Kultur University for a free seminar supported by OWASP. Fundamentally the topic will be about Cyber Wars, but also, will include;

• What is OWASP, OWASP Projects, seminar, society, etc.
• Internet as a new social and cultural domain
• Cyber world as a new milieu
• Why do we need a security perspective?
• First aggressions on the Internet
• Size and Shapes of threats
• Threat hierarchy of timeline
• Organized cyber crimes and cyber wars
• Cyber World and International Relations
• Terrorism and Cyber Terrorism
• How can we prepare for the future ?

Date: Tuesday, December 29, 2009
Time: 12:00pm – 1:30pm
Location: İstanbul Kültür Üniersitesi, Ataköy Kampüsü, Önder Öztunalı Konferans Salonu

http://www.webguvenligi.org/etkinlik/sunum-istanbul-kultur-universitesi.html
http://www.owasp.org/index.php/Turkey#tab=Meetings.2FConferences
http://www.owasp.org/index.php/Turkey#tab=Local_News.2FBrochure

Due to cost and compatibility with legacy systems, the most popular form of user authentication continues to be a secret password.

• Users may write them down or share them, so that they are no longer really secret.
• Passwords can be guessed, either by a person or a program designed to quickly try many possibilities.
• Passwords may be transmitted over a network either in plaintext, or encoded in a way which can be readily converted back to plaintext.
• Passwords may be stored on a workstation, server or backup media in plaintext, or encoded in a way which can be readily converted back to plaintext.

The fundamental and the biggest problem is remembering complex passwords for the people. When people have trouble remembering their passwords, they do one or more of the following things:

• Write down their passwords — and reduce security to the protection afforded by a piece of paper.
• Forget their passwords — and require frequent assistance from a computer help desk organization to reset it.
• Use very simple, easily compromised passwords.
• Reuse old passwords as often as possible.

The number of possible password combinations is calculated by taking the number of legal characters in a password, and raising that number to the number of characters in the password. The possibilities for some likely combinations are shown below:

Users must be obliged to choose their passwords from the widest possible set of characters, subject to the constraints of the systems where those passwords reside. For example, most mainframes do not distinguish between uppercase and lowercase, and only allow three punctuation marks (fourth row in the table above).

It is possible to divide creating secure passwords into two basic criterias; password length and password complexity. The passwords length is important to increase sample space of the probability, so at least 7 characters passwords must be used. However, this is not enough to provide protection. Additionally, password complexity is the supplementary precaution for the password security. The complexity consists of using lower case alphabets, upper case alphabets, numbers and special characters.

So with these information above, how can it be possible to create secure passwords?

The first thing to fallow Comlen rule. Never heard about it ? Don’t worry ! this is what i called it… Comlen means enough complexity with enough length. For example, 8 unique characters with 4 complexity units (1 uppercase, 1 lowercase, 1 number, 1 special char). As I mentiioned you above, these kind of password structures are not easy remembered unfortunately. Even remembering the complex passwords is the best solution, if you cannot do that, you can use password manager programmes. Using password management tool to store passwords should really become a habit. Anytime you create a password, note it down on a password manager tool, that will encrypt the password and store it safe for you. Another deal is using passphares to remember them. If you don’t want to use password management tool, Use Passphrase to easily remember the passwords. You can use initials of a song or a phrase that are very familiar to you. for e.g. “Passwords are like underwears, change yours often!” phrase can be converted to a strong password “Prlu,Curs0!”

There are common senses below. All the following points are nothing new and very much common senses. But most of the time, we tend to ignore these items.

1. Create unique passwords every time.
2. Change your passwords for all your accounts once every 6 months.
3. Never write down your passwords.
4. Don’t share with anyone.
5. Never keep the same password for two different sites.
6. Don’t type your password when someone is looking over your shoulder.
7. Never send your password to anybody in an email.
8. Change password immediately when they are compromised.
9. Don’t use the “Remember password” option on the browser without setting the Master Password.
10. Don’t type your password on a computer that does not belong to you.

There is a simple python function which produces complex passwords:

1. Reboot
2. Hold apple + s down after you hear the chime.
3. When you get text prompt enter in these terminal commands to create a brand new admin account (hitting return after each line):
   • mount -uw /
   • rm /var/db/.AppleSetupDone
   • shutdown -h now
4. Reboot

Or you can just type "password username" and change your user’s password after mounting "/"

If you look at the real time CSI investigation cases, you can easily easily that the threats generally comes from the ones who are in the closers circle of relationships.

This is same in Cyber World. Recent surveys indicate that better than 50 percent of business with an Internet server have experienced remote attack. That’s an impressive figure, however, a far higher percentage of business are attacked from within. 

Every year, thousands of business suffer demonstrable damages at the hands of disgruntled employees. In a recent case, a programmer was fired from a medical billing firm. Then the programmer run a script that deleted a month’s worth of billing records. The firm had no backups and therefore lost thousands of dollars. Cases like that are common.

Why are internal attacks so prevalent ?

The first and the simplest reason of why internal attacks so prevelant than the remote attacks is attacking a network or a system from inside is far easier.

Authorized users can have access to information that remote users can not. This is understandable. Furthermore, local users already enjoy some level of trust, not only simply at a network level but also human level. This is a major advantage.

Authorized or trusted users can gain or already have more and more information about the company and its local mechanisms, etc. Therefore, these kind of information can provide the local attackers to find new, creative and wide attack vectors and surfaces.

Assume an employee in a data processing center of a university. He is responsible from the switching and routing stuff. So, he has a big chance to packet sniffing in the local network and can see the flowing traffic. Besides then, if he is malice person, he can use his trusted human level in order to gain critical information about the users via social engineering, like e-mail passwords, local user passwords, etc. The attack surface is really wide.

Is it possible to prevent all the internal attacks and make the internal network more secure?

The answer to that question has very complex meanings and changeable dynamics. We can never say that there is 100 percent of security. However, we can raise the security level and can control and forestall the threats as much as possible.

It is possible to simply divide ensuring at least a minimal level of internet security into three fundamental parts. The first part is that clear and understandable policies must be written to make the users aware of security. The second and critical step of increasing the security level is that making the users aware of the policies. Moreover, access levels must be well-organized and need-to-know based access control lists must be prepared.

Many firms have no such policies and their administrative folks believe that users ignore the policies even if they are clearly set forth. That may or may not be true. However, that is no reason the avoit writing policies. Besides that, policies may not prevent your users snooping around, but if you do have written policies, you have the ammunition to dismiss that emplotee on the spot.

Some reports suggest the average employee in a small business spends up to an hour a day surfing the web for personal use — perhaps looking at video or file-sharing websites, playing games or using social media websites such as Facebook.

It’s not just time that this activity could cost you. Analyst reports show that the number of malware and virus threats is increasing by more than 50 percent each year, and many of these destructive payloads can be inadvertently introduced to the network by employees.

"It’s very easy for a rootkit to be hidden in a game or a video clip, and a novice user may not notice anything out of the ordinary," warns Graham Titterington, a principal analyst with Ovum.

The best advice is to constantly update and patch your IT systems to ensure you are protected against new threats as they emerge, advises Paul Vlissidis, a technical director with NCC Group. "Don’t rely on monthly or quarterly security downloads," he says. "The time between vulnerabilities being discovered and then exploited is shrinking all the time, so it’s important to update patches and antivirus software regularly, and ideally layer several antivirus products rather than using just one."

There are now a staggering number of ways that information can be taken from your computer networks and released outside the organisation. Whether it’s an MP3 player, a CD-ROM, a digital camera or USB data stick, today’s employees could easily take a significant chunk of your customer database out of the door in their back pocket.

"These types of devices are effectively very portable, very high-capacity hard drives," says Andy Kellett, a senior research analyst with Butler Group. "Someone can walk away with up to 60GB of data on a USB stick, so it’s not a trivial matter."

Research conducted by Websense found that a quarter of UK workers who use PCs at work admit copying data onto mobile devices at least once a week. In addition, 40 percent say they use USB sticks to move data around, and a fifth have revealed their passwords to third parties

In addition, Kellett recommends considering whether to block access to web-based email and data-storage services, such as Gmail. "If someone can store confidential documents to an online storage site, that information is completely beyond your control," he says.

Finally, consider locking down networks to prevent wireless access using Bluetooth or Wi-Fi — except for authorised users with authorised devices. "Information loss over Bluetooth on an unsecured network is very difficult to detect indeed," says Kellett.

Using SNMP it is possible to obtain the condition of a hard-drive partition, uptime of Switches, Routers, UPS, etc or traffic density on the port of a Router, etc. and run into Application Layer on TCP/IP stack. Furthermore, it runs multitude devices and operation systems such ;

• Core Network Devices (Routers, Switches, Hubs, Bridges, and Wireless Network Access Points)
• Consumer Broadband Network Devices (Cable Modems and DSL Modems)
• Consumer Electronic Devices (Cameras and Image Scanners)
• Networked Office Equipment (Printers, Copiers, and FAX Machines)
• Network and Systems Management/Diagnostic Frameworks (Network Sniffers and Network Analyzers)
• Networked Medical Equipment (Imaging Units and Oscilloscopes)
• Manufacturing and Processing Equipment, etc. 

The agent module which works and collect the information on the intended device, the manager part that interacts with the agent and takes the data from it, additionally, network management element which works on the manager and provides all the devices visible, traceable and reconfigurable, are the three main components of the SNMP protocol in order to work properly.

SNMP is a request-wait for apply based protocol. Network Management Component sends a request to a device that consist of Agent module, and after that the Agent returns the reply of the request to network management component. Management and Monitoring issues are handled five different types of messages in SNMPv1 which is is formally defined in RFC1157 : GetRequest, SetRequest, GetNextRequest, GetResponse, and Trap.

A single SNMP message is referred to as a Protocol Data Unit (PDU). These messages are described using Abstract Syntax Notation One (ASN.1) and translated into binary format using Basic Encoding Rules (BER). SNMP request messages are sent from managers to agents. Request messages can poll the agent for current performance or configuration data, ask for the next SNMP object in a Management Information Base (MIB), or modify configuration settings. SNMP agents should reliably decode request messages and process the resulting application data.

OUSPG’s research focused on the manner in which SNMPv1 agents and managers handle request and trap messages. By applying the PROTOS c06-snmpv1 test suite to a variety of popular SNMPv1-enabled products, the OUSPG revealed the following vulnerabilities:

VU#107186 – Multiple vulnerabilities in SNMPv1 trap handling

SNMP trap messages are sent from agents to managers. A trap message may indicate a warning or error condition or otherwise notify the manager about the agent’s state. SNMP managers must properly decode trap messages and process the resulting data. In testing, OUSPG found multiple vulnerabilities in the way many SNMP managers decode and process SNMP trap messages.

VU#854306 – Multiple vulnerabilities in SNMPv1 request handling

SNMP request messages are sent from managers to agents. Request messages might be issued to obtain information from an agent or to instruct the agent to configure the host device. SNMP agents must properly decode request messages and process the resulting data. In testing, OUSPG found multiple vulnerabilities in the way many SNMP agents decode and process SNMP request messages.

Vulnerabilities in the decoding and subsequent processing of SNMP messages by both managers and agents may result in denial-of-service conditions, format string vulnerabilities, and buffer overflows. Some vulnerabilities do not require the SNMP message to use the correct SNMP community string.

The CERT Advisory goes on to report the impact of these vulnerabilities:
    1. unauthorized privileged access
    2. denial-of-service attacks
    3. unstable behavior (service interruptions)
The CISO needs to keep the following concerns in mind when managing risk in the enterprise.

1. Threat: Fuzzing – Exposed Shared Secrets: A major vulnerability of SNMP v1/v2c is that the shared secret is sent in the clear; it is not encrypted. This is true whether the SNMP request is querying counter information, inspecting topology data, or reconfiguring the device. Since the shared secret is not hidden, an attacker can monitor the SNMP traffic to determine network topology and harvest those shared secrets. Among hackers, this is called fuzzing; amongst security professionals, this is Packet Sniffing.

   For example, using SNMP v1/v2c in an insecure network such as a DMZ means an attacker can monitor SNMP traffic and get community strings to perform their own queries or reconfigure devices using SNMP SET. By monitoring SNMP traffic or performing a query directly, an attacker can quickly determine the sysObjectID for each device. The sysObjectID tells the hacker the kind of operating system (OS) the device has. Knowing which OS allows the attacker to determine a suitable target and pick suitable tools to use against that target.
    

2. Threat: Service Interruptions: Vulnerabilities with decoding and processing the SNMP request message (whether a trapor request) in various software products is exploited by the Badly Formed SNMP Trap Attack. The impact of this attack is to blind the management software (prevent it from receiving more traps by causing it to crash) or blind the agent (making it unable to be queried by causing it to crash). The ability of the management software to continue to manage is degraded at best or disabled at worst.

   From within a DMZ, an attacker can reach the management software in the secure network when holes in the firewall are open to allow SNMP traffic or SNMP traps through directly. The attacker constructs special packets with ASN.1 decode errors. When the management console receives the message, it may exit abnormally. When critical daemons exit abnormally, the management software is degraded, causing service
   interruptions.
    

3. Threat: Denial Service : The denial-of-service attack disables management software by sending to a host more SNMP traffic than the host can process. The backlog of traffic to process causes the SNMP agent or manager to dedicate an unbalanced amount of CPU to process the attack’s traffic.

   From within a DMZ, an attacker can flood SNMP traps to the management console when SNMP traps are permitted to flow through firewalls from the DMZ to the secure side. This flood of traps (whether they are bogus or legitimate) causes the management software to backlog. The software uses too much CPU while processing the backlog, causing the management software to stop functioning effectively.

4. Threat: Unauthorized Privilege Access: This threat is the most feared by system managers – a vulnerability that can provide the attacker elevated, privileged access on a host or network device. A common vulnerability is caused by buffer overflow, but is specific to the software processing the SNMP packet.

   If an attacker determines SNMP v1/v2c SET community strings, the attacker can execute privileged commands. On networking devices, privileged commands may be used to reconfigure the device to behave undesirably. With advanced host agents, commands may be sent to the agent, which then execute in privileged state.

Today, mitigating risks with the SNMP protocol involves the choice of one or more mitigating factors:

• using SNMPv3 (not v1 or v2c),
• deploying an IPS appliance to protect against denial-of-service, or
• a management protocol proxy firewall which verifies SNMP traffic to ensure its authentic and valid as well as mitigating SNMP-based attacks.
• changing the community strings after set up SNMP
• keeping the protocol up to date

All the Resources are in the Reference Page.

Struggling to obtain the scarce sources, the differences during the tactical and strategical analysis process while reaching to the same target, controversies in ideological and religious systems, socio-economical standards and class struggles are considered to be the main reasons of disagreements during the interaction processes of people. These disputes may turn into conflicts with time if it is not intervened.

In general perception, the concept of conflict is perceived as a wicked act and it makes people hurt, however, conflicts are disputes between opposing individuals or groups and they are imposed based activities against others. The physical controversies or violences are the extreme examples of the disagreements and in many cases the differences can be solved before turn itself into that kind of ultimate conditions.

In general, the managers are criticized if there is a disagreement or conflict, but this is a faulty perception. Opposite of this perception, differences will be in everywhere and almost in every cases. So, the important key is how to manage these disputes and prevent turning itself to a conflict. Some people think that the conflict must be solved immediately and some think that the disagreement will be solved by itself in time. These approaches which are criticized theoretically can cause negative situations in practicle life. The controverties that is drifted or is not intervened, can be improved itself and turn into conflict in time. On the other hand, the ones who think that the disagreements or conflicts must be solve immediately, can over-lock the integrality of the issue and can become distance from efficient solutions. Hastiness is not quite best act in order to find and optimum solution. This conceptually sounds like Gestalt and I will write about it later.

A conflict has a dynamic structure, it is not static. In that case, the most important thing is the analyzing this dynamic structure. A well-analyzed conflicts consist of many hints that show all the phases of conflicts and can give extra information about how you can manage it. Actually, from the beginning to the end, it is possible to divide the phases of conflicts into six main parts;

• Basic differences
• Disagreement
• Irreconcilability
• Campaign
• Legal Challenge
• Violence

The basic deffrence which reaches the violence phase, does not mean that it passed all the phases. In fact,  most of conflicts in violence phase has very complicated structure. Sometimes, the phase process can be invertible, it depends on the psychological, sociological and economical aspects of the people who have the differences.

Next, I will write about some more technical information about the topics below;

• Conflict Resources
• Sociology in Conflicts
• Emotional Points of Conflicts
• Strategy in Conflict Management
• Communication in Conflict Management Process

In commemoration, she wrote a poem:

In this way and that I tried to save the old pail
Since the bamboo strip was weakening and about
to break
Until at last the bottom fell out.
No more water in the pail!
No more moon in the water!

• 26/04/2009 -- Midnight Excursion (0)

wget -r –level=0 -E –ignore-length -x -k -p -erobots=off -np -N http://www.shibumidojo.org/something/directory

Here are the options:

-r : Recursive retrieving (important)
–level=0: Specify recursion maximum depth level (0 for no limit), very important
-E: append “.html” extension to every document declared as “application/html”
useful when you deal with dirs (that are not dirs but index.html files)
–ignore-lenght: Ignore “Content-length” http headers, sometimes useful when dealing with bugged CGI programs
-x: Force dirs, create an hierarchy of directories even if one would not been created otherwise
-k: here’s one of the most useful options, it converts remote links to local for best viewing
-p: download ll the files that are necessary for proper display of the page
(not so reliable when dealing with JS code but useful)
-erobots=off: turn off http robots.txt usage
-np: no parent, do not ascend to parent dir when retrieving recursively,
one of the most useful function I’ve seen

The performance of the players differ from one day to another. Why cant they be more stable? and Why cant the player achieve his ideal performance?

The motivation behind the high performance can be examined in two main parts. The first part is having necessary technical skills and physical conditions. The next part is having necessary mental skill. If one of them is missing, then the player cannot achieve his own ideal performance.

Right consideration and right starting;

Dr. Loehr emphasize the importance of right consideration in his book "Mental Toughtness Training for Sports", and says; "being mentally strong and achieving the ideal performance is a process can be learned ". Addition to Dr. Loehr’s emphasis there are other required conditions for mental readiness;

• To motivate oneself: The player guides oneself, determines his purposes and moves to that purposes.
• To be positive and realistic: The player does not repudiate, does not try to find an excuse, does not divert the truth. He is realistic and acts positive. Never thinks about the defeat. The player knows his omissions and tries to fix it.
• To be sure: The player does not get afraid of pressure, oppositely the pressure motivates him to be successful. The conditions are not important, the important thing is he never gives up. He is a strong-willed warrior.
• To be ready and eager: The player has to be ready for everything, has to be peaceful, energetic, and should always try to get his potential.
• To focus and be sensitive: The player has a stable concentration and he feels if things are right or not. He can take responsibility of all kind of situation and takes care of his environment.

Beating yourself

The most famous players believe that the biggest competitors are themselves. The first thing that has to be learned is defeating yourself and this learning process makes defeating the others easy. It is very important that the player should recognize the things prevented him to achieve his potential ideal performance and also to be who he wants to be. In addition to latter condition, the player also should turned these mental barriers to positive sensations and behaviors. That is why, doing the best is related with showing the ideal performance, to reach ideal performance is not all about the results.

Focusing on winning or losing is completely wrong strategy. To concentrate on the results forces the player to make mistakes. Stress level starts to increase and bad performance occurs.

In that case, it is needed to desire first, then to be stronger and ready mentally. The player just gives his words and moves. This is the key of success.  And here are some examples to preach self-motivation of the way of success and also its tao.

• I always try to do my best and completely give myself what I do
• In spite of everything, I always stay positive
• I take all responsibilities of my thoughts and acts.
• I never try to find worthless excuse if there is something wrong

John Wooden who is the most famous Basketball coach says "Success is a peace and serenity. It starts trying to do the best you can do and to be the best you can be".

First of all, I should give some information about what algorithm is and where we use them. After that I will give an introduction to Graph Algorithms and keep its details to next articles If you look the header of the doc you can see a version number, it means that i will be updating these article series periodically.

An algorithm is a formula or a set of steps that helps us to solve a particular problem. Normally we use many kinds of algorithms during our life in order to solve problems. As you may guess easily, there are different problems and different solutions which means  many algorithms. Many different problems can be modeled as graphs and we use graph algorithms to solve them. These writing is about one of them named Graph Algorithms

Lets start with a simple algorithm to understand what it is. For instance, lets assume we want to cook omelette.  We have cheese, eggs, oil, salt and the others needs. These are what we have and what we want is a well-prepared omelette. Now we think about the steps of the work.

You can see the steps of the omelette on the example in step by step. However, in some case, you may turn back to the previous step, and these cases happen via loops and clauses. Anyway, I guess it is easy to understand what exactly algorithm is with that example.

Of course, there is not only that way to figure the algorithms but also there are many ways and flow charting is one them. There are two figure below shows you calculation of N factorial with two ways; classical and recursive. You may give some minutes to them if you  dont have any knowledge about flow chart and try to understand what is happening there. I strongly recommend the ones who don’t have any idea that try to write all the steps of calculation like above and then restudy to charts.

There are many kinds of algorithms.

Now after this introduction to algorithm concept we can turn back to our topic. Graph theory provides a language for talking about the properties of relationships. You can see the graphs almost everywhere, in an electric circuit, computer networks, the houses on the road, etc.

More precisely, a graph G = (V,E) consists of a set of vertices(node) V together with a set E of vertex pairs or edges. Graphs can be used to represent essentially any relationship. For example, think about a cities, roads (edges) and the places (nodes).

Several fundamental properties of graphs impact the choice of the data structures used to represent them and algorithms available to analyze them. The first step in any graph problem is determining the flavors of graphs you are dealing with:

Think about the roads which are edges, there are two individual kind of roads according to their directions, like double and single. You can use double-way roads both coming and going, however you can use highways just one way. Now using this metaphor, we can say that, the roads only one ways are directed edges from one node to other node. Other case, it is undirected, because there is no specification for the direction and all the communication channels are open both nodes. As you can see from figure there are directions between the nodes.

Look at the graph figure above, if there was a value on edges then it would be Wighted graph. Knowing the weights of edges is the same as knowing the distance between two places. So, using that tiny information we can say that the graph above is a directed unweighted graph.

Sometimes there can be cycles in the graphs, this is logical; again when you think about the roads of places, you can see the cycles. These kind of graphs are called Cyclic graphs. The figure above again cyclic graph and also directed and unweighted. B-C-E-D-B this is the cyclic part of it.

Soon…..