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Random Image Steganography in Spatial DomainDr. Diwedi Samia

1, Dipesh Aawa2

2NIST,2Boal, 2Inia

agrawaldipesh@aiLcom

b- Steganography is an art of hiding information insome media. This paper describes various image steganography

techniques, based on spatial domain and by considering pixelvalues in binary format. Spatial domain is based on physicallocation of pixels in an image. Generally bit gray level or colourimages can be used as a cover to hide data. Again binary

representations of these pixels are considered to hide secretinformation. Random bits from these btes are used to replace

the bits of secret. In this paper, many steganography techniquescan be used like Least Signicant Bit (LSB), layout management

schemes, replacing only 's or only zero's from lower nibblefrom the bte are considered for hiding secret message in an

image. Along with these techniques, some more methods areproposed, based on selection of random pixels from an image andagain secret data is hidden in random bits of these randomlyselected pixels. For this purpose, many parameters of an image

are considered like physical location of pixels, intensity value ofpixel, etc.

w Steganography, LSB, Raster Scan, Random scan,

Layout Management

I. INTRODUCTON

Stegaography is a tecique of hidg secret formatio

ay of media lke - mage, text, audio ad video. Messa?

eto be hidde is cocealed aother le called cover meda.Combiatio of secret message ad cover le is called as

-stegoll. This stego is trasmitd oer a etork to specieddestatio. Data ca be hdde Ipxels of a mage.

A pixel has some teger value, based o the tesity ofcolour that is displayed by a pixel. This teger value ca be

convered ino binary forma, i.e. he form of bye of 1 'sd O's. Ididua bts o tese bytes c be used to desecret formatio. These bits ca be selected radomly oma bte ad replaced ith a secret data. Pixels which data is

to be hidde are also selected radomly, om a mage.Thus, pixels used for data hidg ca be selected usig

various algoritms ad teciques, described this paper are- ayout maagemet schemes []. Also, bits om eachselected pixel ca chose radoml usig some algorims,like SB [].

This paper proposes ew methods for selectio of pixelsom a mage, radomly for hidg secret data. Also some

teciques are proposed to select bits radomly om the bteswhich represet pixels of a image.

II. EATED WO

Stegaography is oe more iformatio secrity tool likeCrptography ad atermarkg. Crptography There are somay image stegaography techiques based o spatialdomai. Spatial doma meas actual physical locatio of a

pixel a image. While hidg data a pixel, the physicallocatio of a pixel is cosidered ad the the biary format of

that pixel value is used to hide the data.

Least Signcant Bit:

Oe of the simplest ad very popular teique ofstegaography is east Sigicat Bit (SB). this

tecique, least sigicat bit or bits of a pixel are replacedby the bits of data to be hidde [].

SB ca be exteded up to 4 least sigicat positiosom a bte, i. e. we ca replace four bits of hidde data with

the origal value of a pixel, whose biary value is of 8 bits.So, out of 8 bits, at max 4 bits ca be used to hide data. eca replace last two bits also. Replacig fo bits, may causedistortio a image due to oticeable chage colour adtesity of a mage.

B. Replacing only 's or Zero's:

other tecique is, to cosider biary values of a pixel

d epce all 's ony from a for ea ignifican bts,with the bits of data to be hidde [4].

Same way we can do for O's ony. This wll damic.allyhide umber of bits or btes, the cover medm. Detectof hidde data will be very difcult for ay iuder.

C. Layout Management hemes:

other approach ca be, to cosider layout of pixels oma image various ways, ad accordg to the logicalsequece of pixels, data ca be hidde the SBs, up to fo

positios at max [].

Pixels ca be cosidered ay sequece like, startig omcee positio ad comig outside i a rectagular way.Similarly, startg om outer pixel, goig towards the cee a rectagular way. This approach is sho ge givebelow.

other approach is, cosider pixels i sake movemet,diagoal movemet, startg om top le or top right orbottom le or bottom right.

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Hece we ca use ay aragemet of pixels ad ca makelogical sequece of these pixels to hide secret data.

T P P

iJl

Fig. I Logical sequence of pixels om centre to outer side

Stng Point Tenan2 Point

\

.

-l.

Fig. 2 Logical sequence of pixels towards centre om outer side

. PROPOSED WO

our work, we proposed folloig methods of hidg databased o radom bits of radom pixel positios of a image.

Replacing Intermediate Bit

Usig this tecique, ay bit or ay termediate bit oma give bte (of a pixel value) ca be replaced by the bit of adata to be hidde.

For ex. Origal data is -

10101110

01010100

LE I

COVRDAA

00011101 11001101

11101111 10110001

Message to hide is - 000

11110001

10101000

Bits are replaced accordig to ay radom sequece omSB to MSB positio

LE IT

COVRDAA + DAA= G

10111110 00011111 11001101 111000015t

Bitn

a Bit6

t

Bit4

t

Bit

01011100 11101111 10100001 101010104

t

h Bit 3f

d Bit5t

h Bitn

d Bit

Uderled bits shows the bits of secret message arereplaced ith the bits of origal data at that positio.

B. Raster Scan Principle

This method is simila to Raster Sca prciple ofdisplayig a image o RT display. I this, pixels omalteate horizotal les ae used for replacig the secretiformatio. A smple SB scheme ca be used for pixels ofrst horizotal le. The secod le is skipped. Aga thrdle is used to hide secret formatio ad so o. e ca also

use : terlacig, 4: terlacg ad so o.osider origal data -

LE III

COVRDAA

10101110 00011101 11001101

11100010 01011011 00111001

10101010 11100010 00101010

00000000 00011100 1100001 0

M o d - 000

11110001

11000111

01011100

11111110

Message will be hidde usig followig tecique.

LE IV

COVRDAA + DAA= G

00 0000 0000 000011100010 01011011 00111001 11000111

000 000 00000 00000000000 00011100 1100001 0 11111110

above table, idividual bits of secret message arereplaced ith bits of origal pixels. Pixels are selectedaccordg to the raster sca method.

Random an Principle

This method is similar to Radom Sca prciple ofdisplayig a image o RT display. this, the sequece, which pixels are dra, they are used to hide secretiformatio. Aga ay simple data hidg algoritm lke SB,ca be used to hide secret iformatio. By this method, dataca be hidde radom pixels a mage.

10101110

11100010

10101010

00000000

LE V

COVRD

00011101 11001101

01011011 00111001

11100010 00101010

00011100 1100001 0

M o d - 000

11110001

11000111

01011100

11111110

Message will be hidde usig followig tecique.

LE VI

COVRDAA + DAA= G

00 00011101 000 000011100010 0000 00111001 11000111000 11100011 0000 0101110100000000 00000 1100001 0

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I this table, dividual bits of secret message are replaced stegaography, based o spatial doma stegaography adwith dividual bits of origal pixels. here pixels are radom bit stegaography.selected radomly.

D. Colour based data hiding

I this scheme oe xed colour is used to hide secret data.

Itesity values of this xed colour are coverted to biayformat ad the secret formatio is hidde this biay data.

For ex. cosider a gray scale 8 bit image, havg tesityvalues ragg om 0 to 55.

Suppose we have xed a colour, whose tesity value is55. Bary value of this is - 000.

e ill d total umber of pixels om a mage, havgthe same tesity value.

Suppose there are 50 pixels foud. The we ca hide secretiformatio these 50 pixels, usig ay data hidg

tecique like - SB etc.e ca exed this tecique by takg more tha oe

xed colour of pixels, om a mage.

E Shape based data hiding

I this scheme, ay shape ca be take to hide the data a image. For ex. cosider a iagular shape. As sho gure below.

Fig. 3 Shape based datahidg

Accordig to gure, secret formatio ca be hidde oly the pixels which are available iagular shape, stead ofhidg secret formatio whole image. e ca use ayshape havg ay dimesios.

e ca exted this tecique, by usig ay shape of aydimesio at ay place a mage.

IV.ONUSIONI this paper, alog with existg teciques of image

stegaography, some ew methods for hidg data magesare discussed. Data ca be hidde pixels. Physical locatioof these pixels ca be decided usig the teciques which aredescribed i this paper. Aer selectig radom pixels, thesecret data ca be hidde radom bits, which are

represeted the btes of biary digits. hile selectig thesepixels, may parameters om a mage are cosidered for ex.olour of pixels, physical locatio of pixels etc. Based o

these parameters ad by cosiderg some more parametersom a mage, we ca derive some more teciques of image

EFEENES[1] li K Hmood, B B Zaindan, -an overview o n hiding nformaton

techniques in imagesl journa of applied sciences 10 (18): 20942100

2010 ISSN 18125654.2010 Asian network for scientic information.

[2] Saneev Manchanda, Mayank De S. B Sngh -Customized andsecure image steganography through random numbers ogic Signal Processing:an International Joual, Volume 1: issue (I).

[3] Mohammad anvir Parvez, Adnan Abdulziz Gutub, -RB ntensitbased variabe bits image stegaographyl 2008 IEEE AsiaPacic ServicesComputing Conrence.

[4] Rengaraan mirtharaan, Jiaohua Qin, John Bosco BalagurRayappan. Inrmation echnology Jour nal 11(5): 566576 2012ISSN 181256382012 sian Network for Scientic Infoation.

Dr. Samidha Dwivedi Sharma is cently working as a Head of theDepment of Information Technology. NRI Group of Institutions.Bhopal. MP. IDIA She has of more than 15 Yes teachingexperience in different esteemed university She Worked as aChairperson (HOD) of Information System with King Abdulaziz

University (Female Section). Rabigh. Saudi rabia om 2010 to2011 e as been teacig for 15 yearsShe completed herbachelor's degree in Science (BSc) with Mathematics subject in 1992om Dr H S Gour Central University (formerly. Sagar University)Sagar. M p India She received her Master degree in ComputerApplication in the year 1997 om Barkatullah University. Bhopal.

India She has obtained Ph D Degree in Computer Science andApplication om Dr H S Gour Central University (formerly. Sagar

University) Sagar. M p India Her elds of interests e DatabaseManagement Systems. Mobile database. Data Structure and mobile

computing She has published 5 national d inteational researchpapers She is a life member ofSTE

Dipesh Agrawal was bo on January 6. 1983 in Nasik. Mahashtra,India He has received the BE degree in Computer Engineering frommrutvahini College of Engineering, Pune University, Pune,Maharashtra. India, in Sept 2007 He is cently pursuing his MTechdegree in Information Technology om NRI Institute of Science andTechnology. RGTU University. Bhopal. Madhya Pradesh. India Hisareas of interest include Image Processing. Steganography andInformation Security