Learning Wireless Security WEP Methods

WEP is a first standard security & encryption used on wireless, WEP (Wired Equivalent Privacy) is a method of securing a wireless network, also called Shared Key Authentication. Shared Key Authentication is the authentication method that requires the use of WEP. WEP encryption uses a key that is inserted (by the administrator) to a client or access point. This key must match from a given access point to the client, with the inserted client to authenticate to the access point.

Here is the process of Shared Key Authentication :

• Client has asked the association to the access point, this step is the same as the Open System Authentication.
• Access point sends challenge text to the client in a transparent manner.
• Client will provide a response by encrypting the challenge text using the WEP key and sends back to the access point.
• Responded to an access point client response, the access point will perform encryption decrypt the response from the client to verify that the challenge text is encrypted using the WEP key as appropriate. In this process, the access point will determine whether the client has given the corresponding WEP key. If the WEP key provided by the client are correct, then the access point will respond positively and immediately to client authentication. But if the client entered the WEP key is incorrect, then the access point will respond negatively and will not be given a client authentication. Thus, the client will not be authenticated and not associated.

Data communication via the IEEE 802.11, Shared Key Authentication is more secure than it seems from the Open System Authentication, but in reality are not. Shared Key instead opened the door for intruders or crackers. It is important to understand two streets used by WEP. WEP can be used to verify the identity of the client during the process of shared key authentication, but can also be used to decrypt data sent by the client via the access point.

WEP has many flaws, among others:

• The problem of weak keys, RC4 algorithm used can be solved.
• WEP uses a static key.
• Problem of initialization vector (IV) WEP.
• Message integrity problem Cyclic Redundancy Check (CRC-32).

WEP consists of two levels, namely 64-bit key, and 128 bits. Actually, the secret key on a 64 bit WEP key is only 40 bits, while 24bit is an Initialization Vector (IV). Similarly, the 128 bit WEP key, secret key consists of 104bit.

The attacks on WEP weaknesses include:

• The attack on the weaknesses of the initialization vector (IV), often called the FMS attack. FMS stands for the name of the three inventors of the IV weakness Fluhrer, Mantin, and Shamir. This attack was done by collecting a weak IV as much as possible. The more weak IV is obtained, the sooner discovered the key that is used.
• Getting a unique IV data obtained through the packet to be processed for WEP key cracking process more quickly. This method is called chopping attack, first discovered by h1kari. This technique only requires a unique IV thus reducing the need for IV are weak in WEP cracking.

Both of the above attacks require considerable time and packet, to shorten the time, the hackers usually do traffic injection. Traffic Injection is often done by collecting the ARP packet and then sends back to the access point. This resulted in the collection of initial vectors is easier and faster. Unlike the first and second, to attack traffic injection, required specification of tools and applications that start rarely found in stores, ranging from chipsets, firmware version, and versions of drivers, and not infrequently have to do patching of drivers and applications.

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Learning SDL Simple DirectMedia Layer

Simple DirectMedia Layer (SDL) library is a free cross-platform multimedia, written in C, which creates an abstraction layer on top of various software platforms, graphics and sound and thus can control the video, digital audio, CD-ROM drive, sound, string, load sharing of objects, timer and network.

This abstraction allows programmers to write multimedia applications once and run on many operating systems: the official version supports Linux, Windows, BeOS, MacOS and Mac OS X, FreeBSD, OpenBSD, BSD / OS, Solaris, IRIX, and QNX source code, but does not offer official support for Windows CE, AmigaOS, Dreamcast, Atari, NetBSD, AIX, OSF/Tru64, RISC OS, and SymbianOS.

The history.
Sam Lantinga created the library, originally released in early 1998, while working for Loki Software. It occurred to him when he took the application from Windows to Macintosh. He used to bring Doom SDL under BeOS (see the Doom source ports). Some other free libraries seem to be working with SDL, OpenAL, and SMPEG it.

The library has a link to almost any existing programming language from the euphoria of the popular C + +, Perl, Python (via pygame), Pascal conosiuti less like or pliable. That and the fact that it is licensed under the LGPL, SDL is a common choice for multimedia applications.

SDL itself is very simple: It only works as a wrapper that provides a lightweight, multi-platform support for 2D operations on pixels, sound, file access, event handling, timers, threads, and much more. It is often used as a supplement to the OpenGL graphics output settings and provide input mouse and keyboard, which is beyond the scope of OpenGL.

The library is divided into several subsystems, such as video nominees (both surface and function to handle OpenGL), Audio, CD-ROM, joystick and timer subsystem. Apart from the basic low-level support, there are several libraries that provide additional functionality official support. These include the "standard library" provided on the official website and incorporated into official documentation:

* SDL_image - support for multiple image formats
* SDL_mixer - complex audio functions, especially for sound mixing
* SDL_net - network support
* SDL_ttf - support for TrueType font rendering
* SDL_rtf - Render simple Rich Text Format

SDL has the word "layer" in the title because it really is a wrapper function through a specific operating system. The main goal of the SDL is to provide a common framework to access this feature.
For the SDL is designed as a bunch of source code is divided into separate modules for each operating system in order to make calls to the underlying operating system. When SDL is compiled, the correct form selected for the appropriate operating system.

In Microsoft Windows, SDL provides a wrapper for DirectX, which in turn is a wrapper for the driver. DirectX version 5 using SDL, but SDL 1.2 (current stable release) requires DirectX 7 by default. Sam Lantinga has begun plans to use DirectX 8 in future releases of SDL [1].

On the X11 platform, including Linux, SDL Xlib is used to communicate with X11 graphics for the event.

In Mac OS X uses Quartz SDL.

Subsystem and syntax.

The syntax of the SDL is based on the function, all transactions made in the SDL run by passing parameters to functions. Special facilities are also used to store specific information that you need to use SDL. There are different SDL subsystems to characterize the function below:

* The video subsystem, events and threads - this provides management functionality for video, multi-threading, and events.
* Audio subsystem - provides audio capability.
* Timer Subsystem
* Subsystem joystick
* CD-ROM Subsystem

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