10-09-2016, 03:11 PM
1454495372-ProjectPaper.docx (Size: 261.7 KB / Downloads: 5)
ABSTRACT
A Steganographic Technique is usually evaluated in terms of the visual quality and the Embedding Capacity. This Project Presents a adaptive Steganographic scheme that is capable of both visual degradation and providing a large embedding capacity.The data is encrypted using the Blowfish Algorithm which is the variable key size of 32 bits to 448 bits.Due to 521 iterations in Blowfish Algorithm,it is more secure and efficient than any other.The Encrypted cipher text is then converted into binary form which make easier to hide in images. Hiding of data into an image involves two algorithms such as Random number generation and Range algorithm.The Random number generation is helpful to select pixel positions in which the data is to be hide in the group of pixel contains 8 pixels each.The Range Algorithm is used to hide the data based on the intensity of the pixels.Based on the intensity value, the embedding capacity will increase.
The existing system has the problem of having minimum embedding capacity and the encryption algorithm used were easily cracked because of small key size.This project uses variable key length of size from 32bits to 448bits,algorithm called Blowfish Algorithm.
This project resolves the problem of embedding larger amount of data in a single image and it does not change the quality of image throughout the process. The embedding capacity in previous technique is maximum of 2bits per pixel.But this project increase the embedding capacity upto maximum of 5/6 bits per pixel based on the pixel intensities. Also, the data is encrypted using the Blowfish Algorithm,which is a symmetric key block cipher of variable key length of 32bits to 448bits.The previous encryption technique uses the key size of 128bits,256bits which is easily cracked.In case of Blowfish Algorithm it is not easily cracked because it requires 521 iterations. It is a Feistel network, iterating a simple encryption function 16 times.
KEYWORDS:Blowfish Encryption, Random number generator, RangeTechnique, Decryption process.
CHAPTER 1
1.1 INTRODUCTION:
With the development of the Internet, information processing technologies and the rapid development of communication, it is necessary to share information resources. Nevertheless, the Internet is an open environment so information security has becoming increasingly important.Also, Security of wireless networks is main aspect and the process of cryptography plays an important role to provide the security to the wireless networks.The process of encrypting the data alone will not give more security.Hence,we providing the security via hiding those encrypted data into an image and then send it to the receiver.ie Steganography.
Steganography is different from cryptography. The main objective of cryptography is to secure communications by using encryption techniques. But steganography techniques are used to hide the messages, which makes difficult for a third party / person to find out the message.Watermarking and fingerprinting related to steganography are basically used for intellectual property protection.
Data hiding in images, the data is encrypted using Blowfish algorithm.The encrypted text is divided into 24 bit blocks.Then it converted into binary form.The Random Generator is used to select the pixel positions in which the data is to be hide.Then the Range Technique is used to embed the data into the corresponding pixel positions. The reverse process is done in decryption side.
1.2 OBJECTIVE:
The main objective of this project is to increase the hiding or embedding capacity in images without changing the quality of the image and also to improve the security of the algorithm.To enhance the security this project uses the Encryption algorithm called Blowfish Algorithm.Also to increase the hiding capacity this project uses Range Technique and Random number Generator.The Random Number Generator is used for randomly select the pixel positions in which the Data going to be hide.The Range Technique is used for hiding the data in the corresponding pixel positions based on the pixel intensities.By fixing the range based on the intensities we can embed the more data in an image without changing the image quality.
1.3 REAL TIME APPLICATIONS:
IP telephony:
IP telephony or Voice over IP (VoIP) for instance, is a real-time service which enables users to make phone calls through IP data networks. It is one of the most important services of IP-based networks and is impacting the entire telecommunications landscape.
An IP telephony connection consists of two phases in which certain types of traffic are exchanged between the calling parties: signalling and conversation phases. During the first phase certain signalling protocol messages, for example SIP (Session Initiation Protocol) messages [9], are exchanged between the caller and callee. These messages are intended to set up and negotiate the connection parameters between the calling parties. During the second phase, two audio streams are sent bi-directionally. RTP (Real-Time Transport Protocol) [1] is most often utilised for voice data transport and thus packets that carry the voice payload are called RTP packets. The consecutive RTP packets form an RTP stream.
CHAPTER 2
LITERATURE REVIEW:
2.1 EXISTING SYSTEMS:
DESATA ENCRYPTION STANDARD
DES is a block cipher that uses shared secret key for encryption and decryption. DES algorithm takes a fixed-length string of plaintext bits and transforms it through a series of complicated operations into cipher text bit string of the same length.In the case of DES, each block size is 64 bits. DES also uses a key of 56 bits to customize the transformation, so that decryption can only be performed by those who know the particular key used to encrypt the message. There are 16 identical stages of processing, termed rounds. The Broad level steps in DES are as follows:
1. In the first step, the 64-bit plain text message is handed over to an Initial permutation (IP) function.
2. The initial permutation is performed on plain text.
3. The IP produces two halves of the permuted message;
Left Plain Text (LPT) and Right Plain Text (RPT).
4. Now, each of LPT and RPT go through 16 rounds of encryption process.
5. In the end, LPT and RPT are rejoined and a final permutation (FP) is performed on the combined block.
6. The result of this process produces 64-bit cipher text.
Rounds: Each of the 16 rounds, in turn, consists of the broad level steps.
AES:ADVANCED ENCRYPTION STANDARD
The AES cipher is almost identical to the block cipher Rijndael cipher developed by two Belgian cryptographers, Joan Daemen and Vincent Rijmen. The algorithm described by AES is a symmetric-key algorithm, meaning the same key is used for both encrypting and decrypting the data. The number of internal rounds of the cipher is a function of the key length. The number of rounds for 128-bit key is 10. Unlike its predecessor DES, AES does not use a Feistel network. Feistel networks do not encrypt an entire block per iteration, e.g., in DES, 64/2 = 32 bits are encrypted in one round. AES, on the other hand, encrypts all 128 bits in one iteration. This is one reason why it has a comparably small number of rounds.
LSB:LEAST SIGNIFICANT BIT
The most basic and important image Steganographic Technique is Least Significant Bit [2, 7] embedding technique. In this technique data can be hidden in the least significant bits of the cover image and the human eye would be unable to notice the hidden image in the cover file. This technique can be used for hiding images in 24-bit, 8-bit or gray scale format. In this technique, least significant bit of each pixel is replaced with secret message bit until message end. When using a 24 bit image one can store 3 bit in each pixel by changing a bit of each if the red, green and blue color components. An 800 x 600 pixel image can store 1,4400,00 bits or 180,000 bytes of embedded data. For example a 24 bit can be as follows: (10110101 01101100 10101101) (10110110 11001101 00111110) (10110101 01100011 10001110) The number 150 which binary representation is 10010110 is embedded into the least significant bits of this part of the image, the resulting grid as follows: (10110101 01101100 10101100) (10110111 11001100 00111111) (10110101 01100010 10001110)
Although the number is embedded into the first 8 bytes of the grid, only the 3 underlined bits need to be changed according to the embedded message. On an average, only half of the bits in an image will need to be modified to hide a secret message using the maximum cover size.
2.1.1 DRAWBACKS:
Disadvantages OF DES AND AES:
1) Its key size is too small by current standards and its entire 56 bit key space can be searched in approximately 22 hours.
2) It was recognized that DES was not secure because of advancement in computer processing power.
3) AES is challenging to implement in software.
Disadvantage of LSB:
1)We can embed only minimum number of data in the image.
2.2 PROPOSED SYSTEM:
BLOWFISH ALGORITHM FOR ENCRYPTION:
1) Blowfish is block cipher 64-bit which can also be used as a replacement for the DES algorithm. It takes a variable length key, ranging from 32 bits to 448 bits; default 128 bits.
2) Blowfish is fast as its encryption rate on 32-bit microprocessor is 26 clock cycles per byte.
3) It is compact as it can execute in less than 5 kb memory.
4) It is simple because it uses only primitive operations like addition, XOR and table lookup, making its design and implementation simple.
5) It has a variable key length upto a maximum of 448 bits long making it both flexible and secure.
6) No attack is known to be successful against this. Blowfish is unpatented, license-free, and is available free for all uses. Blowfish has variants of 14 rounds or less.
7) Blowfish is considered to be the best out of all encryption algorithms.
RANGE ALGORITHM AND RANDOM GENERATOR FOR HIDING IMAGE:
1)The Random Number generator is helpful to select the pixel positions randomly.
2)The Range Algorithm is used to embed the data in corresponding pixel positions based on the intensity values.