Stegnography final
-
Upload
heena-bohra -
Category
Technology
-
view
1.719 -
download
0
description
Transcript of Stegnography final
{
STEGNOGRAPHY
AN ART OF HIDING INFORMATION
STEGANOGRAPHY
-- - AN ART OF HIDING DIGITAL INFORMATION
REASONS FOR SELECTING TOPIC
It was indeed difficult to select one topic from the long list hat was provided to us. We both believe that it is technology that binds this entire society together. The growing use of technology makes it extremely important for all of us to secure or hide our confidential information to the greatest extent possible. It is only with this guarantee of personal security that technology will be able to grow by leaps and bounds.
It was with this basic idea that we chose the topic of steganography-so that we would get the chance to learn and explore more about the lesser known world of steganography
INTRODUCTION
STEGANOGRAPHY :
STEGANOGRAPHY COMES FROM THE GREEK
WORD, IT MEANS COVERED OR SECRET
WRITING.
STEGAN-O-GRAPHY
COVERED WRITING
“The goal of steganography is to hide messages in such a
way that no one apart from the intended recipient even knows
that a message has been sent.”
This can be achieve by concealing the existence of
information within seemingly harmless carriers or cover
It can be understand by the following figure.
It supplements cryptography
And provides additional security to the information being transmitted.
Difference between cryptography and steganogaphy..
• At times these two technologies seem to converge while the objectives of the two differ. The two systems also use different methods altogether
• Cryptographic techniques "scramble" messages so if intercepted, the messages cannot be understood.
• Steganography, in an essence, "camouflages" a message and makes it invisible thus reducing the chance of a message being detected.
• This technology has in fact been used throughout recorded history.
History of Steganography
Steganography ancient origins can be traced back to 440 BC, from the Histories of Herodotus
Demeratus sent a warning about a forthcoming attack to Greece by writing it on a wooden panel and covering it in wax.
Histiaeus, who shaved the head of his most trusted slave and tattooed a message on it. After his hair had grown the message was hidden. The purpose was to instigate a revolt against the Persians.
STEGANOGRAPHY UNDER VaRIOUS MEDIA
Steganography in “TEXT”
Steganography in “IMAGES”
Steganography in “AUDIO”
STEGANOGRAPHY IN TEXT
I T I N VO LV E S T H R E E T Y P E S O F C O D I N G :
L I N E - S H I F T C O D I N G : H E R E , T E X T L I N E S A R E
V E RT I C A L LY S H I F T E D T O E N C O D E T H E D O C U M E N T
U N I Q U E LY.
W O R D - S H I F T C O D I N G : T H E C O D E W O R D S A R E
C O D E D I N T O D O C U M E N T B Y S H I F T I N G T H E
H O R I Z O N TA L L O C AT I O N S O F W O R D S W I T H I N T E X T
L I N E S , W H I L E M A I N TA I N I N G A N AT U R A L S P A C I N G
A P P E A R A N C E .
F E AT U R E C O D I N G : I N F E AT U R E C O D I N G ,
C E RTA I N T E X T F E AT U R E S A R E A LT E R E D , O R N O T
A LT E R E D , D E P E N D I N G O N T H E C O D E W O R D .
STEGANOGRAPHY IN IMAGES
Image Compression: Image compression offers a solution to large image files. Two
kinds of image compression are lossless and lossy compression.
Both methods save storage space but have differing effects on
any uncompressed hidden data in the image.
“Lossy” JPEG(Joint Photographic Experts Group) format files,
offers high compression, but may not maintain the original
image's integrity. Hence it is called “lossy”.
“Lossless” compression maintains the original image data
exactly, It is thus more favoured by stenographic techniques. E.g.:
(BMP ),(GIF) Formats.
IMAGE-BASED TECHNIQUES
O Least Significant
Bit Insertion
O Masking and
Filtering
LSB INSERTION
Replaces least significant bits with the message to be encoded
Most popular technique when dealing with images
Simple, but susceptible to lossy compression and image manipulation
LSB - Example
A sample raster data for 3 pixels (9 bytes)
may be:Inserting the binaryvalue for
A (10000001)changes
4 bits00100111 11101000 1100100000100110 11001000 1110100011001001 00100111 11101011
00100111 11101001 1100100000100111 11001000 1110100111001000 00100111 11101011
Best to use a gray scale palette or one with gradual changes in shades
Otherwise, it is best to use images with “noisy areas” – areas with ample color variation and without large areas of solid color
LSB Continued…
GRAYSCALE PALETTE
NEBULA PALETTE
“NOISY AREAS” - Example
Renoir painting
LSB - Uses
• Storing passwords and/or other confidential information
• Covert communication of sensitive data
• Speculated uses in terrorist activities• Being widely used to hide and/or transfer
illegal content
Masks secret data over the original data by changing the luminance of particular areas
During masking, it embed the message within significant bits of the cover image
Not susceptible to lossy techniques because image manipulation does not affect the secret message
MASKING & FILTERING
MASKING & FILTERING - Uses Digital Watermarking – provides
identification pertaining to the owner; i.e. license or copyright information
- Invisible vs Visible
Fingerprinting – provides identification of the user; used to identify and track illegal use of content
Visible Watermark - Example
STEGANOGRAPHY IN AUDIO
Methods of Audio Data Hiding
Low-bit encoding :
Phase coding :
Echo data hiding :
LSB CODING: Least significant bit (LSB) coding is the simplest way to embed information in a digital audio file. By substituting the least significant bit of each sampling point with a binary message, LSB coding allows for a large amount of data to be encoded.
PHASE CODING:Phase coding relies on the fact that the phase components of sound are not as perceptible to the human ear as noise is. Rather than introducing perturbations, the technique encodes the message bits as phase shifts in the phase spectrum of a digital signal, achieving an inaudible encoding .
EChO-HIDING: In echo hiding, information is embedded in a sound file by introducing an echo into the discrete signal. Like the spread spectrum method, it too provides advantages in that it allows for a high data transmission rate and provides superior robustness when compared to the noise inducing methods.
STEGANALYSIS
Steganalysis is the art and science of
detecting a secret communication.
Hiding a message will most likely leave
detectable traces in the cover medium.
The information hiding process changes the
statistical properties of the cover, which is a
steganalyst attempts to detect.
The process of attempting to detect statistical
traces is called statistical steganalysis.
ADVANTAGES AND DISADVANTAGES
ADVANTAGES :
Difficult to detect and Only receiver can detect.
It can be done faster with large no. of software's.
Provides better security for sharing data in LAN,MAN & WAN.
DISADVANTAGES:
The confidentiality of information is maintained by the algorithms, and
if the algorithms are known then this technique is of no use.
Password leakage may occur and it leads to the unauthorized access of
data.
If this technique is gone in the wrong hands like hackers can be very much
dangerous for all.
Steganography Sample Website
Here is the link for Sample Stenographic tool Website:
http://mozaiq.org/
My Questions
1. Salutations, Mr. Robertson of CIS 5371. The Florida Society of Math and Cryptography is proud to present you with an small exam for qualification into our society. The key for passing is studying. Cryptography is rigorous and only those with patience in themselves pass. We have an exam PO Box in Tallahassee. But please submit by 12/12.
Salutations, Mr. Robertson of CIS 5371. The Florida Society of Math and Cryptography is proud to present you with an small exam for qualification into our society. The key for passing is studying. Cryptography is rigorous and only those with patience in themselves pass. We have an exam PO Box in Tallahassee. But please submit by 12/12.
ANSWER
The Cryptography exam key is in PO Box 1212.
Bibliography:
WWW.GOOGLE.COM
WWW.WIKIPEDIA.COM
WWW.WEBOPEDIA.COM------IMAGES
WWW.THUNDERSTONE.COM
WWW.CITI.UMICH.EDU
WWW.GARYKESSLER.NET/LIBRARY/STEGANOGRAPHY.HTML
SOME ARTICLES