Abstract: A Steganography method of embedding audio or video information in an image is presented in this paper.
InSteganography is the art and science of hiding communication.Essentially, the information-hiding process in a steganographic system startsby identifying redundant bits.we use aimage steganography to send confidential audio or video message secretly. Forhiding the data in an image, we use the least significant bit method ofinsertion. All image files are made up of bits,whichgive the colour intensity for each pixel in the image. Any color pixel is made of a combination ofRED-GREEN-BLUE (RGB) wherein each RGB components consists of 8 bits.
In the 8 bits for each colour, if the leastsignificantbit is used to insert the encrypted text, the resultant colour does notvaryfrom that of the original colour. Hence,our proposed system inserts the twice-encrypted file into an imagefile. secret audio or video message is encryptedwith the help of ABE encryption algorithm and then the encrypted audio messageis embedded into a cover image by using LSB technique. And then decrypted thesecret message in the cover image with a specified recipient.
Keywords:· STEGNOGRAPHY· LSB · ABE 1.Introduction The word steganography is a Greekwords steganos, meaning “covered, concealed, or protected”, andgraphene meaning “writing”. Steganography is the method of coveringand hiding messages in a medium called a cipher text. Itis the practice of encoding/embedding secretinformationin a manner such that the existence of the information is invisible. Theoriginal_les can be referred to as cover text, cover image, or cover audio.
Afterinsertingthe secret message it is referred to as stego-medium. A stego-key is usedforhiding/encoding process to restrict detection or extraction of the embeddeddataSteganographicsystems, can be divided into two categories, one is in which the veryexistenceof the message is kept secret, and non steganographic systems, in which theexistenceofthe message need not be secretThis paper is an attempt uses an image as a covermedium to hide an audio or video file withoutmakingnoticeable changes to the file structure and contents of the image based on two LeastSignificantBit insertion method of the low part of the image. general diagram of stegnography 2.Encryption using ABEAttribute-basedencryption (ABE), introduced by Sahai and Waters (2005), offers an expressiveway to defineasymmetric-keyencryption schemes for policy enforcement based on attributes. Here both a usersecret key andciphertextare associated with sets of attributes.
There are two flavours of ABE defined,i.e. ciphertext-policyattribute-based encryption (CP-ABE) and key-policyattribute-based encryption (KP-ABE). Architecture of ABE EncryptionI will use a CP-ABE Policy InCP-ABE, auser encrypts the data according toapredicate (access policy) defined over attributes, such that only the partythat possesses a secret key associatedwiththe attribute set satisfying the predicate is able to decrypt the ciphertext,CP-ABE schemes are more desirable due to theirflexibility allowing encryption according to theaccess policy. Architecture of both encryption and decryption3.
Algorithmof CP-ABE: CP-ABEScheme Outline• Setup. A randomized algorithm Setup(k)takes in as input a security parameter and provides a setof public parameters(PK) and the master key values (MK). • Encryption. The algorithm Enc(M, T ,PK) is a randomized algorithm that takes as input themessage to be encrypted(M), the access structure T which needs to be satis_ed and the publicparameters(PK) to output the ciphertext CT.
We can say, that the encryption algorithmembeds theaccessstructure in the ciphertext such that only those users with attributessatisfying T will be ableto decrypt and retrieve the message M.• Key-Generation. The KeyGen(MK, PK, A)algorithm takes as input the master key values(MK),the public parameters (PK) and the attribute set of the user (A), and outputsfor the user aset of decryption keys SK which con_rms the users possession ofall the attributes in A and no otherexternalattribute. • Decryption.The decryption algorithm Dec(CT, SK, PK) takes as input the ciphertext CT,theuser secret keys SK and the public parameters PK, and it outputs theencrypted message (M) ifandonly if the attributes A embedded in SK satisfy the access structure T whichwas used whileencrypting the ciphertext CT. i.e If T (A) = 1 then message M isoutput else, it outputs?. 4.
Embedding Process :Indealing with LSB coding methodologies (LSB) least significant bit is modifiedto embed data. In terms of phase encoding scheme the part of carrier file is tobe replaced with the reference phase which represents hidden data.The LSB is the lowest significant bit inthe byte value of the image pixel.
The LSB based image steganographyembeds the secret in the least significant bits of pixel values of the coverimageThe least signi_cant bit (in otherwords, the 8th bit) of some or all of the bytesinside an image is changed to abit of the secret message.Increasing or decreasing the value by changing theLSB does not change the appearance of the image; much so the resultant stegoimage looks almost sameas the cover image. In 8 bit images, one bit ofinformation can be hidden. C(i,j)is equal to the message bit m of secret massage to be embedded, C(i,j)remainunchanged; if not, set the LSB of C(i, j) to m. The message embeddingprocedureis given below-S(i,j)= C(i,j) – 1, if LSB(C(i,j)) = 1 and m = 0S(i.
j)= C(i,j), if LSB(C(i,j)) = mS(i,j)= C(i,j) + 1, if LSB(C(i,j)) = 0 and m = 1whereLSB(C(i, j)) stands for the LSB of cover image C(i,j) and m is the nextmessagebit to be embedded.S(i,j)is the stego imageAswe already know each pixel is made up of three bytes consisting of either a 1ora 0.Forexample, suppose one can hide a message in three pixels of an image (24-bitcolors).Suppose the original 3 pixels are (1110101011101000 11001011)(0110011011001010 11101000)(1100100100100101 11101001) Asteganographic program could hide the letter “J” which has a position74 intoASCIIcharacter set and have a binary representation “01001010”, byaltering thechannelbits of pixels. (1110101011101001 11001010)(0110011011001011 11101000) (11001001 00100100 11101001)Inthis case, only four bits needed to be changed to insert the charactersuccesfully.Theresulting changes that are made to the least signi_cant bits are too small toberecognisedby the human eye, so the message is e_ectively hidden. The advantageof LSBembedding is its simplicity and many techniques use these methods .
LSBembedding also allows high perceptual transparency.Data Embedding Algorithm:Theembedding process is as follows.Inputs :Cover image, stego-keyand the secret audio fileOutput: stego imageProcedureStep 1: Extract the pixels of the coverimage.Step2: Extract the audio file. Step3: Extract the characters from the Stego key. Step4: Choose first pixel and pick characters of the Stego key and place it in firstcomponentof pixel. Step5: Place some terminating symbol to indicate end of the key.
0 has been usedasa terminating symbol in this algorithm. Step6: Insert the audio file in each firstcomponent of next pixels byreplacingit. Step7: Repeat step 6 till all the audio file has been embedded.
Step8: Again place some terminating symbol to indicate end of data.Step9: Obtained stego image. DataExtraction Algorithm:Theextraction process is as follows.Inputs:Stego-image, stego-keyOutput:Secret audio or video message. Procedure:Step1: Extract the pixels of the stego image.Step2: Now, start from first pixel and extract stego key characters from firstcomponentof the pixels. Follow Step3 up to terminating symbol, otherwise followstep4.Step4: If this extracted key matches with the key entered by the receiver, thenfollowStep 5, otherwise terminate the program.
Step5: If the key is correct, then go to next pixels and extract secret messagecharactersfrom first component of next pixels. Follow Step 5 till up to terminatingsymbol,otherwise follow step 6.Step6: Extract secret message. Audio Encryption Algorithm:Inputs:cover image, key and audio file Output :ciphertext (audio file)..
1.The cover and secret images are read and converted into the unit8 type.2.The audio or video file is encrypted.3.
ABE algorithm can be used to encrypt the secret audio or video file4.These encrypted file can be embedded the image using LSB technique.5.
The stego-image, which is very similar to the original cover image, is send tothe receiver.6. while the receiver can receive and thedecrypt the secret audio fileExample : RGB(cover image)We use a LSB technique to change the colorpixels in the cover image. the original quality of the image cannot be changed.It is a original audio file andthen encrypted using attribute based encryption.The encrypted audio file is,Conclusion:Anew approach of embedding an audio or video file into the image using LSB basedimageSteganographyhas been successfully developed and implemented as discussed in this paper. Themain aim of this researchworkwas embedding of audio or video into image as a case of image steganography. Intest cases, theaudio or video file has been successfullyembedded and extracted from the image