A Secured System for Information Hiding in Image Steganography using Genetic Algorithm and Cryptography
Encryption is used to securely communicate data in open networks. Each type of data has its own structures; therefore according to the data the different techniques should be used to defend confidential data. Among them digital images are also very popular to carry confidential information in untrusted networks. . For pleasing the defense of data hiding and communication over network, the proposed system uses cryptographic algorithm along with Steganography. In the proposed system, the file which user want to make secure is firstly compressed to shrink in size and then the compressed data is altered into cipher text by using Blow Fish cryptographic algorithm and then the encrypted data is concealed in the image.
In order to hide the information over the image in complex manner the genetic algorithm based technique is implemented which is used to evaluate the valuable pixels where the data can be hide in a secure manner. In addition of that, for hiding the information in images, the LSB (least significant bits) based steganographic method is used after the selection of eligible pixels.
The implementation of the anticipated technique is performed using MATLAB and for performance evaluation the time and space complexity is computed. In addition of that a comparative study of the proposed technique using the image steganographic technique is also performed in terms of PSNR and MSE. According to the computed performance the proposed technique is adoptable for hiding information in image securely additionally that consumes less space complexity.
In cryptography the data is transformed into an unreadable format during encryption process and during decryption data is again recovered in its original format. On the other hand in data steganography the data is encapsulated in a specific format of multimedia files to hide the sensitive information and during the recovery of data the information is retrieved from its original format without any modification on its cover.
Steganography and cryptography are techniques used to shelter information from unwanted parties but neither technique alone is perfect. Once the actuality of hidden information is publicized or suspected, the reason of Steganography is somewhat defeated. The asset of Steganography increases by combining it with cryptography. In this work the recommended system practices both cryptography and steganography for enhanced privacy and security.
Even if these modus operandi are merged directly, there is a chance that the intruder may discriminate the original message. Therefore, here we applied both of them together with more security levels to get a very highly secured system for data hiding. In the proposed system to thwart the influence of Steganalysis method, Genetic Algorithm is used for pixel selection of image where data is to be hide so that finding of clandestine information become multifarious.
- Low PSNR value.
- Low image quality.
- Poor image contrast.
The security is an essential concept of the digital data, it becomes more sensitive when the data is travelled through the untrusted environment. Here the untrusted environment can be any openly accessible network where anybody can use the network facilities. In the presented work, the image based secure steganography is the primary motive to hide the information. Therefore a number of techniques are evaluated and a hybrid technique using the steganography and traditional cryptographic approach is proposed and implemented.
The proposed technique includes the goodness of AES based data cryptography and the LSB based image steganography for hiding the sensitive data on the given cover image. The proposed technique first compress the information to reduce the size of data to be hide, then utilizes the AES cryptographic technique to generate the cipher text.
This cipher text is further sub-divided into small fixed size blocks to hide into the image. On the other hand the key image is treated using the genetic process therefore a small modification on traditional genetic algorithm is made to select the rows and low intensity pixels to hide data on LSB of image. The implementation of the proposed technique is performed using the MATLAB and their performance in terms of space complexity, time complexity, MSE and PSNR is evaluated. MSE and PSNR and obtained values are much better than existing techniques.
• High PSNR value.
• High image quality.
• High image contrast.
Processor Type : Pentium -IV
Speed : 2.4 GHZ
Ram : 128 MB RAM
Hard disk : 20 GB HD
Operating System : Windows 7
Software Programming Package : Matlab R2014b