Digital communication has become an essential part of infrastructure nowadays, a lot of applications are Internet-based and in some cases it is desired that communication be made secret.
Consequently, the security of information has become a fundamental
issue. Two techniques are available to achieve this goal: Encryption and steganography is one of them. Using cryptography, the data is transformed into some other gibberish form and then the encrypted data is transmitted. In steganography, the data is embedded in
an image file and the image file is transmitted. This paper proposed a system that combines the effect of these two methods to enhance the security of the data. This proposed system encrypts the data with a crypto algorithm and then embeds the encrypted text in an image file. The embedding process is done with help of stego-key, and the detection or reading of embedded information is possible only having this key. The stego key (user-specified or default) is used not only to facilitate random selection of bytes for hiding message file bits but also is used to encrypt the message file.
The encryption method is based on XORing the message bytes with random numbers generated by a pseudo-random number generator whose seed is derived from the stego key. Here we also calculate the message digest of image and embed into image file to check
integrity of message contents.
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