Jaringan nirkabel (Inggris: wireless network) adalah bidang disiplin yang berkaitan dengan komunikasi antar sistem komputer tanpa menggunakan kabel. Jaringan nirkabel ini sering dipakai untuk jaringan komputer baik pada jarak yang dekat (beberapa meter, memakai alat/pemancar bluetooth) maupun pada jarak jauh (lewat satelit). Bidang ini erat hubungannya dengan bidang telekomunikasi, teknologi informasi, dan teknik komputer. Jenis jaringan yang populer dalam kategori jaringan nirkabel ini meliputi: Jaringan kawasan lokal nirkabel (wireless LAN/WLAN), dan Wi-Fi. Jaringan nirkabel biasanya menghubungkan satu sistem komputer dengan sistem yang lain dengan menggunakan beberapa macam media transmisi tanpa kabel, seperti: gelombang radio, gelombang mikro, maupun cahaya infra merah.

Pada tahun 1970 Norman Abramson, seorang profesor di University of Hawaii, mengembangkan komputer pertama di dunia jaringan komunikasi, ALOHAnet, menggunakan biaya rendah seperti ham-radio. Dengan bi-directional topologi bintang, sistem komputer yang terhubung tujuh ditempatkan lebih dari empat pulau untuk berkomunikasi dengan komputer pusat di Pulau Oahu tanpa menggunakan saluran telepon.

"Pada tahun 1979, FR Gfeller dan U. Bapst menerbitkan makalah di Proceedings IEEE pelaporan percobaan jaringan area lokal nirkabel menggunakan komunikasi infra merah disebarkan. Tak lama kemudian, pada tahun 1980, P. Ferrert melaporkan percobaan penerapan kode satu radio spread spectrum untuk komunikasi di terminal nirkabel IEEE Konferensi Telekomunikasi Nasional. Pada tahun 1984, perbandingan antara infra merah dan CDMA spread spectrum untuk komunikasi jaringan informasi kantor nirkabel diterbitkan oleh IEEE Kaveh Pahlavan di Jaringan Komputer Simposium yang muncul kemudian dalam IEEE Communication Society Magazine. Pada bulan Mei 1985, upaya Marcus memimpin FCC untuk mengumumkan ISM band eksperimental untuk aplikasi komersial teknologi spread spectrum. Belakangan, M. Kavehrad melaporkan percobaan sistem PBX nirkabel kode menggunakan Division Multiple Access. Upaya-upaya ini mendorong kegiatan industri yang signifikan dalam pengembangan dari generasi baru dari jaringan area lokal nirkabel dan diperbarui beberapa lama diskusi di radio portabel dan mobile industri.

Generasi pertama dari modem data nirkabel dikembangkan pada awal 1980-an oleh operator radio amatir, yang sering disebut sebagai radio paket ini. Mereka menambahkan komunikasi data pita suara modem, dengan kecepatan data di bawah 9.600-bit / s, untuk yang sudah ada sistem radio jarak pendek, biasanya dalam dua meter band amatir. Generasi kedua modem nirkabel dikembangkan FCC segera setelah pengumuman di band eksperimental untuk non-militer penggunaan spektrum penyebaran teknologi. Modem ini memiliki kecepatan data yang diberikan atas perintah ratusan kbit / s. Generasi ketiga modem nirkabel ditujukan untuk kompatibilitas dengan LAN yang ada dengan data tingkat atas perintah Mbit / s. Beberapa perusahaan yang mengembangkan produk-produk generasi ketiga dengan kecepatan data di atas 1 Mbit / s dan beberapa produk sudah diumumkan oleh waktu pertama IEEE Workshop on Wireless LAN.

Adapun jaringan nirkabel dalam bidang sensor atau biasa disebut Jaringan Sensor Nirkabel (Wireless Sensor Network/WSN). Jaringan sensor nirkabel adalah jaringan perangkat nirkabel yang saling berhubungan yang tertanam dalam lingkungan fisik untuk mengukur kondisi lingkungan seperti suhu, suara, tingkat polusi, kelembapan, angin, dan sebagainya.

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How to choose your Information Security Training

In the past couple of years, the economy has struck hard on organizations seeking to educate their employees. Training budgets have been cut down, and choosing the right course that will give you real Return on Investment is not an easy job. This is especially true in the offensive InfoSec arena, where training standards and qualifications are weakly defined. So how can you make sure your getting your money’s worth ?

Welcome to our “10 questions you should be asking your InfoSec Training Provider“.

1. What are the objectives of the training ?

What will the training do for you ? Anyone promising you that you will be a “hardcore penetration tester” or a “security expert” after their 5 day class has never run a pentest, or otherwise has no clue what they are talking about. Learning *any* profession in 5 days is unrealistic, let alone one as complex as IT Security, or penetration testing. This is one of the first questions I ask before attending a training… its allows me to set my goals for the course and gives me a baseline for my expectations.

2. What topics does the course cover ?

Always read the syllabus of the course you want to attend, before you attend it.  Try finding other people who have taken the class, (if possible) and get their opinion. Try to see if the syllabus follows a reasonable methodology, or if it’s just a collection of topics. If you see a list of 1500 tools on the syllabus – expect to spend around 0.6 minutes per tool. 

3. Who is your trainer ?

Are they well known in their field ? Do they have training experience ? Are they involved in the security community ? Do they practice what they preach? Although these are 4 separate questions, they all relate to one thing – the ability of the trainer to provide the goods you paid so dearly for. Finding a GOOD InfoSec trainer is NOT easy. Most computer genii are usually lacking in their social skills – something a good trainer must have.

4. What previous reviews does the class have ?

Running a few internet searches for the name of your class, or the name of the trainer is a must. Find out what people have to say about their experiences – during and after the class. Although you can’t believe *everything* on the internet, taking an average of all the reviews will usually give you a solid idea of what you are getting into.

5. What is the ratio of students to trainers ?

How many students will there be in the class ? Some training providers cram more than 30 students in one class – often with a single instructor. During a 5 day period, a trainer can’t give personal attention to 30 people, no matter what. In general, smaller classes mean a more intimate environment, more attention from the trainer, and a more productive and engaging experience.

6. What is the ratio between theory and hands-on exercises ?

Remember the famous saying “In theory, there is no difference between theory and practice – But in practice, there is”. If you don’t exercise what you learn, you are less likely to retain or understand it as nothing replaces practical experience. Ask for a rough ratio estimate for “theory VS exercise” for your class – anything above 40% class-time spent on exercises is a good sign. Of course, this greatly depends on the quality of the exercises too.

7. How often is the course updated ? Is the material relevant to modern day situations ?

Learning methods and techniques on antiquated systems will bring you little benefit in the real world. Hacking a Windows 2000 SP4 machine with RCP DCOM doesn’t cut it any more. On the other hand, don’t expect to learn “Bypassing Windows 7 Stack Protection” in an introductory buffer overflows course. You need to gauge the balance between these two elements carefully.

8. What are the pre-requisites for the class ?

How should you prepare yourself for the class? Do you need to refresh your knowledge on certain topics? Nothing is more frustrating than coming to a class, and then lagging behind because you are not up to par with the class requirements. Not good for your learning experience, and not good for your self esteem – on the other hand “no pre-requisites required” might indicate lack of depth. If the pre-requisites were defined well by the training provider, it’s definitely a good resource to use to evaluate the relevancy of the course to you.

9. Is there a certification involved ? What is it’s value ?

The “value” of a certification can be measured in the real world using two main indicators:

• The “market value” of the certification – how popular is this certification in the workforce ? Is the certificate recognized and appreciated by the industry ? And of course, will it help you get a (better) job ?

• The “practical value” of the certification – or as Eddie Murphy would say “WHAT HAVE YOU DONE FOR ME LATELY?”.  What real world skills does the certificate prove? If it proves you can memorize 100 questions, you might not be up to the job when confronted with a real world scenario.

10. What post training benefits are provided?

What ongoing benefits will you get from the training provider, if any ? Is there a continuation path for the training ? Will the trainers be available for future questions or issues that may arise ? Is there a student community you can join, to discuss the course with other student ? Or in other words, what kind of “post customer service” can you expect ?

These 10 questions should cover all the important elements you should verify before committing your valuable time and limited training budget to any service provider. The average person only gets a limited number of training opportunities per year, therefore you should always maximize the return you receive.

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Make Wireless in your home

You have several computers in the house and you want all computers are connected in a small network. Actually there are 2 ways to dial, the first is to use a cable, and that both wirelessly. Which will be discussed here is the wireless connection, because the connection using a cable is less desirable because the need for long cables as well as in terms of aesthetics that are less attractive.

For simplicity, the discussion will be divided form the 4 categories namely, preparation equipment, connect the modem to the router, network settings, and the last is a computer connected to the network wirelessly. Let us begin.

Preparation Tools
the device should be prepared in advance is a cable modem, wireless router, as well as several wireless receivers for computers that need it

Cable modems function as a bridge between your internet service providers. In Indonesia, most services are Firstmedia worth it, despite numerous complaints about poor customer service professional. But if your area is not covered by these services you may be considering using IndosatM2 cable Internet service.

Wireless Router functions for connecting and providing Internet access to all computer or laptop that is connected to the appliance. Some activities that can be done if it is connected to the tool it is, sharing documents between computers, as well as streaming video and audio.

Wireless receiver functions to capture the wireless signal are transmitted by the wireless router. Usually installed on your computer (PC) using a USB or PCI card. But if you use a laptop, usually do not need this tool, because it has a built-in.

Connect the modem and router

We assume you have subscribed to one of the services mentioned above (First media or IndosatM2), it is time you plug your modem into your wireless router using an Ethernet cable (usually included the purchase of this cable modem). Please note in connecting to the router, not to the wrong port. Usually written to modem connection (Internet / WAN) as shown in the picture below (in green)

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Pyrit Tool- GPU Cracker for Attacking WPA/WPA2 PSK Protocols

Pyrit allows to create massive databases, pre-computing part of the IEEE 802.11 WPA/WPA2-PSK authentication phase in a space-time-tradeoff. Exploiting the computational power of Many-Core- and other platforms through ATI-Stream, Nvidia CUDA, OpenCL and VIA Padlock, it is currently by far the most powerful attack against one of the world's most used security-protocols.

WPA/WPA2-PSK is a subset of IEEE 802.11 WPA/WPA2 that skips the complex task of key distribution and client authentication by assigning every participating party the same pre shared key. This master key is derived from a password which the administrating user has to pre-configure e.g. on his laptop and the Access Point. When the laptop creates a connection to the Access Point, a new session key is derived from the master key to encrypt and authenticate following traffic. The "shortcut" of using a single master key instead ofper-user keys eases deployment of WPA/WPA2-protected networks for home- and small-office-use at the cost of making the protocol vulnerable to brute-force-attacks against it's key negotiation phase; it allows to ultimately reveal the password that protects the network. This vulnerability has to be considered exceptionally disastrous as the protocol allows much of the key derivation to be pre-computed, making simple brute-force-attacks even more alluring to the attacker. For more background see this article on the project's blog.

The author does not encourage or support using Pyrit for the infringement of peoples' communication-privacy. The exploration and realization of the technology discussed here motivate as a purpose of their own; this is documented by the open development, strictly sourcecode-based distribution and 'copyleft'-licensing.

Pyrit is free software - free as in freedom. Everyone can inspect, copy or modify it and share derived work under the GNU General Public License v3+. It compiles and executes on a wide variety of platforms including FreeBSD, MacOS X and Linux as operation-system and x86-, alpha-, arm-, hppa-, mips-, powerpc-, s390 and sparc-processors.

Attacking WPA/WPA2 by brute-force boils down to to computing Pairwise Master Keys as fast as possible. Every Pairwise Master Key is 'worth' exactly one megabyte of data getting pushed through PBKDF2-HMAC-SHA1. In turn, computing 10.000 PMKs per second is equivalent to hashing 9,8 gigabyte of data with SHA1 in one second. The following graph shows various performance numbers measured on platforms supported by Pyrit.

You can see Youtube how to use this tool:
http://www.youtube.com/watch?v=HY9Y99bOyhE

To download the latest Pyrit 0.40, please see this link:

http://code.google.com/p/pyrit/downloads/list

For more information about this Pyrit  tool, please see the link below:

http://code.google.com/p/pyrit/

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