Performance analysis of DWT and DCT on steganography

Nowadays, data security has become more important than ever because of technological developments and widely usage of internet. People prefer to use secret communication due to breaking their social life privacy by responsible institutions or they concern about their illegal activities. Secret communication has done by the Cryptology, which converts the content of message to unreadable situation, or has done by Steganography, which hides the existence of the message itself. Cryptology takes attention of curious parties of community by making the messages itself unreadable.On the other hand, making the messages itself unreadable situation, accelerates cracking of cyrpto systems security by technology community. But on the other side, steganography only hides of the existence of message itself. This can not be cause of curiosity of cracking any security systems to reach it's content. Because, you can not have any ambitious about solving a complex security algorithms or trying to crack any security system which can not be seen. The time before our technological era, our encestors of Turkish Republic citizents and at the our encestors old and past goverments, they used old fashioned – according to our age- steganographical communication ways, effectively. According to history tellers they developed their own ways and conduct this science and art branch. But nowadays, we are unfamiliar with steganography itself and it's terminologies. We have to reach the same level which our encestors accomplished in steganography. With the help of the steganography main advantage and taking motivation from this historical background of our community, my master thesis main purpose, to efficiently learn steganography and gain experience about it. To accomplish this purpose, I am going to go to learn and use frequency based steganography algorithms which are DCT, Discrete Cosinus Transform and DWT, Discrete Wavelet Transform. And also to learn them in effective way, I created a scenario about secret data communication. I've hidden a text message in a carrier object with DCT and I've hidden a small picture in a carrier object with DWT. According to this scenario, I've matched these well known frequency based steganography techniques based on their PSNR, Peak Signal to Noise Ratio values. The result going to go to show us which way is the most successfull way of our scenario. With this work, I have experienced about DWT, DCT and LSB, Least Significant Bit which is widely used and known technique to embed secret messages in pictures and used in our work with DCT algorithm. I hope this master thesis paper work will be helpfull for all readers to carry this science to the next level.