Difference between pages "Steganalysis" and "TDMA"

From ForensicsWiki
(Difference between pages)
Jump to: navigation, search
 
m
 
Line 1: Line 1:
==External links==
+
'''TDMA - Time Division Multiple Access'''
===Steganalysis===
+
 
* [http://www.sarc-wv.com Steganography Analysis and Research Center] The Steganography Analysis and Research Center is a Center of Excellence within Backbone Security focused exclusively on steganography research and the development of various steganalysis products and services.
+
TDMA (Time Division Multiple Access), has the largest network in the US.
===Steganalysis Training===
+
 
* [http://www.sarc-wv.com/training.aspx Certified Steganography Examiner Training] A comprehensive two-day training course on steganography and steganalysis techniques provided by the SARC.
+
TDMA is a digital wireless communication method allowing many users to access a single radio frequency without interference. Every individual user is given a unique time slot within each channel. 
===Algorithms and Tools===
+
 
* [http://www.sarc-wv.com/products/stegalyzeras.aspx Steganography Analyzer Artifact Scanner (StegAlyzerAS)] StegAlyzerAS gives you the capability to scan the entire file system, or individual directories, on suspect media using the most extensive steganography hash set publicly availabe for the presence of steganography application artifacts. And, unlike other popular forensic tools, you can perform an automated or manual search of the Windows Registry to determine whether or not any Registry keys or values exist that can be associated with a particular steganography application.  
+
Why use TDMA?  IT increases the efficiency of transmission and offers a number of other advantages. A major pro is it can be easily adapted to transmission of data as well as voice communication. It offers the ability to carry date rates of 64 kbps to 120 mbps, which enables options of communication such as fax, voiceband data, sms, as well as bandwidth intensive apps. TDMA allows the user to have extended battery life since the mobile is only transmitting a portion of the time during conversations. Furthermore, it is the most cost effective technology for upgrading a current analog system to digital.
* [http://www.sarc-wv.com/products/stegalyzerss.aspx Steganography Analyzer Signature Scanner (StegAlyzerSS)] StegAlyzerSS gives you the capability to scan every file on the suspect media for the presence of hexadecimal byte patterns, or signatures, of particular steganography applications in the files. If a known signature is detected, it may be possible to extract information hidden with the steganography application associated with the signature.  
+
 
* [http://www.sarc-wv.com/products/stegalyzerrts.aspx Steganography Analyzer Real-Time Scanner (StegAlyzerRTS)] StegAlyzerRTS is the first commercially available network security appliance in the world capable of detecting the fingerprints and signatures of digital steganography applications in real-time.
+
How it works:
 +
It’s necessary for TDMA to rely upon that fact that the audio signal has been digitized. These signals are divided into a number of milliseconds. TDMA is also the access technique used in the European digital standard, GSM, and the Japanese digital standard, personal digital cellular (PDC). The reason for choosing TDMA for all these standards was that it enables some vital features for system operation in an advanced cellular or PCS environment. Today, TDMA is an available, well-proven technique in commercial operation in many systems.
 +
A single channel can carry all four conversations if each conversation is divided into relatively short fragments, is assigned a time slot, and is transmitted in synchronized timed. 
 +
 
 +
Downfaults:
 +
TDMA can be wasteful of bandwidth because time slots are allocated to specific conversations whether or not anyone was speaking at the given moment. There is an enhanced version however, EDTMA, which attempts to correct this problem. Unlike TDMA which waits to determine whether a subscriber is transmitting, ETDMA assigns subscribers using a dynamic method. The data is sent through pauses which normal speech contains. If the subscriber has something they would like to transmit, it is placed as one bit in the buffer queue.  The system then scans the buffer and notices the user has something to transmit, allocating the bandwidth accordingly. However, if there is nothing to transmit, it goes to the next subscriber. This technique can be 10 times more efficient as analog transmission of TDMA. 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
 
 +
'''References'''
 +
 
 +
[http://en.wikipedia.org/wiki/Time_division_multiple_access TDMA]

Revision as of 22:09, 28 September 2006

TDMA - Time Division Multiple Access

TDMA (Time Division Multiple Access), has the largest network in the US.

TDMA is a digital wireless communication method allowing many users to access a single radio frequency without interference. Every individual user is given a unique time slot within each channel.

Why use TDMA? IT increases the efficiency of transmission and offers a number of other advantages. A major pro is it can be easily adapted to transmission of data as well as voice communication. It offers the ability to carry date rates of 64 kbps to 120 mbps, which enables options of communication such as fax, voiceband data, sms, as well as bandwidth intensive apps. TDMA allows the user to have extended battery life since the mobile is only transmitting a portion of the time during conversations. Furthermore, it is the most cost effective technology for upgrading a current analog system to digital.

How it works: It’s necessary for TDMA to rely upon that fact that the audio signal has been digitized. These signals are divided into a number of milliseconds. TDMA is also the access technique used in the European digital standard, GSM, and the Japanese digital standard, personal digital cellular (PDC). The reason for choosing TDMA for all these standards was that it enables some vital features for system operation in an advanced cellular or PCS environment. Today, TDMA is an available, well-proven technique in commercial operation in many systems. A single channel can carry all four conversations if each conversation is divided into relatively short fragments, is assigned a time slot, and is transmitted in synchronized timed.

Downfaults: TDMA can be wasteful of bandwidth because time slots are allocated to specific conversations whether or not anyone was speaking at the given moment. There is an enhanced version however, EDTMA, which attempts to correct this problem. Unlike TDMA which waits to determine whether a subscriber is transmitting, ETDMA assigns subscribers using a dynamic method. The data is sent through pauses which normal speech contains. If the subscriber has something they would like to transmit, it is placed as one bit in the buffer queue. The system then scans the buffer and notices the user has something to transmit, allocating the bandwidth accordingly. However, if there is nothing to transmit, it goes to the next subscriber. This technique can be 10 times more efficient as analog transmission of TDMA.




References

TDMA