Abstract: covering and hiding messages in a medium called

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 starts by identifying redundant bits.we use a image steganography to send confidential audio or video message secretly. For hiding the data in an image, we use the least significant bit method of insertion. All image files are made up of bits,which give the colour intensity for each pixel in the image. Any color pixel is made of a combination of RED-GREEN-BLUE (RGB) wherein each RGB components consists of 8 bits. In the 8 bits for each colour, if the leastsignificant bit is used to insert the encrypted text, the resultant colour does notvary from that of the original colour. Hence, our proposed system inserts the twice-encrypted file into an imagefile. secret audio or video message is encrypted with the help of ABE encryption algorithm and then the encrypted audio message is embedded into a cover image by using LSB technique. And then decrypted the secret message in the cover image with a specified recipient. Keywords:• STEGNOGRAPHY• LSB • ABE 1.Introduction The word steganography is a Greek words steganos, meaning “covered, concealed, or protected”, and graphene meaning “writing”. Steganography is the method of covering and hiding messages in a medium called a cipher text. It is the practice of encoding/embedding secretinformation in 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. Afterinserting the secret message it is referred to as stego-medium. A stego-key is usedfor hiding/encoding process to restrict detection or extraction of the embeddeddataSteganographic systems, can be divided into two categories, one is in which the veryexistence of the message is kept secret, and non steganographic systems, in which the existenceof the message need not be secretThis paper is an attempt uses an image as a cover medium to hide an audio or video file withoutmaking noticeable changes to the file structure and contents of the  image based on two LeastSignificant Bit insertion method of the low part of the image.   general diagram of stegnography               2.Encryption using ABEAttribute-based encryption (ABE), introduced by Sahai and Waters (2005), offers an expressive way to defineasymmetric-key encryption schemes for policy enforcement based on attributes. Here both a user secret key andciphertext are associated with sets of attributes. There are two flavours of ABE defined, i.e. ciphertext-policyattribute-based encryption (CP-ABE) and key-policy attribute-based encryption (KP-ABE).                  Architecture of  ABE EncryptionI will use a CP-ABE Policy In CP-ABE, a user encrypts the data according toa predicate (access policy) defined over attributes, such that only the party that possesses a secret key associatedwith the attribute set satisfying the predicate is able to decrypt the ciphertext, CP-ABE schemes are more desirable due to theirflexibility allowing encryption according to the access policy.  Architecture of both encryption and decryption3.Algorithm of CP-ABE: CP-ABE Scheme 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 algorithm embeds theaccess structure in the ciphertext such that only those users with attributes satisfying 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 outputs for the user aset of decryption keys SK which con_rms the users possession of all the attributes in A and no otherexternal attribute.• 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 the encrypted message (M) ifand only if the attributes A embedded in SK satisfy the access structure T which was used whileencrypting the ciphertext CT. i.e If T (A) = 1 then message M is output else, it outputs?.4.Embedding Process :In dealing with LSB coding methodologies (LSB) least significant bit is modified to embed data. In terms of phase encoding scheme the part of carrier file is to be replaced with the reference phase which represents hidden data.The LSB is the lowest significant bit in the byte value of the image pixel. The LSB based image steganography embeds the secret in the least significant bits of pixel values of the cover imageThe least signi_cant bit (in other words, the 8th bit) of some or all of the bytesinside an image is changed to a bit of the secret message.Increasing or decreasing the value by changing the LSB does not change the appearance of the image; much so the resultant stego image looks almost sameas the cover image. In 8 bit images, one bit of information can be hidden.C(i,j) is equal to the message bit m of secret massage to be embedded, C(i,j)remain unchanged; if not, set the LSB of C(i, j) to m. The message embeddingprocedure is 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 = 1where LSB(C(i, j)) stands for the LSB of cover image C(i,j) and m is the nextmessage bit to be embedded.S(i,j) is the stego imageAs we already know each pixel is made up of three bytes consisting of either a 1or a 0.For example, suppose one can hide a message in three pixels of an image (24-bitcolors). Suppose the original 3 pixels are(11101010 11101000 11001011)(01100110 11001010 11101000)(11001001 00100101 11101001)A steganographic program could hide the letter “J” which has a position 74 intoASCII character set and have a binary representation “01001010”, by altering thechannel bits of pixels.(11101010 11101001 11001010)(01100110 11001011 11101000) (11001001 00100100 11101001)In this case, only four bits needed to be changed to insert the character succesfully.The resulting changes that are made to the least signi_cant bits are too small to berecognised by the human eye, so the message is e_ectively hidden. The advantageof LSB embedding is its simplicity and many techniques use these methods .LSB embedding also allows high perceptual transparency. Data Embedding Algorithm:The embedding process is as follows.Inputs :Cover image, stego-key and the secret audio fileOutput: stego imageProcedureStep 1: Extract the pixels of the cover image. Step 2: Extract the audio file.Step 3: Extract the characters from the Stego key.Step 4: Choose first pixel and pick characters of the Stego key and place it in firstcomponent of pixel.Step 5: Place some terminating symbol to indicate end of the key. 0 has been usedas a terminating symbol in this algorithm.Step 6: Insert the audio file  in each first component of next pixels byreplacing it.Step 7: Repeat step 6 till all the audio file has been embedded.Step 8: Again place some terminating symbol to indicate end of data.Step 9: Obtained stego image. Data Extraction Algorithm:The extraction process is as follows.Inputs :Stego-image, stego-keyOutput: Secret audio or video message. Procedure:Step 1: Extract the pixels of the stego image.Step 2: Now, start from first pixel and extract stego key characters from firstcomponent of the pixels. Follow Step3 up to terminating symbol, otherwise followstep 4.Step 4: If this extracted key matches with the key entered by the receiver, thenfollow Step 5, otherwise terminate the program.Step 5: If the key is correct, then go to next pixels and extract secret messagecharacters from first component of next pixels. Follow Step 5 till up to terminatingsymbol, otherwise follow step 6.Step 6: Extract secret message.Audio Encryption Algorithm:Inputs: cover image, key and audio file   Output :cipher text (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 to the receiver.6.  while the receiver can receive and the decrypt the  secret audio fileExample :                         RGB(cover image)We use a LSB technique to change the color pixels in the cover image. the original quality of the image cannot be changed. It is a original audio file and then encrypted using attribute based encryption.The encrypted audio file is, Conclusion:A new approach of embedding an audio or video file into the image using LSB based imageSteganography has been successfully developed and implemented as discussed in this paper. The main aim of this researchwork was embedding of audio or video into image as a case of image steganography. In test cases, theaudio or video file has been successfully embedded and extracted from the image


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