Abstract: Steganography is defined as the study of invisible communication. It maintains secrecy between two communicating parties. In image steganography, secrecy is achieved by embedding data into cover image and generating a stego-image. Using Steganography techniques on stego image the security can be improved. For improving second level security, different algorithms can be applied on stego image. So that the result in the improvement of security in terms of execution can be achieved. When it comes to the pro and cons of various Steganographic software, many have been designed; each of them has different features and capabilities for data hiding. Hence, this makes it a wide and attractive field for further research, in which the establishment…show more content… These days, all the information is stored in a digital form. The other objects can be data, image, audio or video. Images are one of the most important carrying media, which can be used for hiding the information [1]. This process of hiding information into another object is referred to as a stenography. There are two techniques available for transmitting the secret information between the communicating parties. One is cryptography [17], in which the structure of the message is scrambled to make it meaningless and can be reconstructed only by the holder of a key. It offers the ability of transmitting the information between communicating parties in a way that prevents the third party from reading it [5]. When secret message is transmitted, it is observable by anyone means it does not attempt to hide the fact that a message exists. The second technique is stenography, which hides the secret message into another object. It does not alter the structure of the secret message, but hides it inside a cover object so that it cannot be seen by any observer. On the other hand, steganography focuses on making the fact that the secret message does not exist within the system. Figure 1.1 shows the general block diagram of…show more content… • Text-based Steganography
In this, the message that is to be sent is rooted firstly in a text file with formatting. The format it based on line-shift coding, word-shift coding, feature coding etc. Reformatting of the text destroys the rooted content hence the technique is not robust [16].
• Image-based Steganography
This Steganography hides the message in the images. This is the most popular technique because of the fact that almost no perceivable changes occur. Some of the commonly used methods of embedding payload in cover image are least Significant Bits (LSB) substitution in which the LSBs of cover image pixel are altered to hide the payload and more data can be hidden in edges [13].
• Audio-based Steganography
This Alters audio files so that they contain hidden messages. The techniques are LSB manipulation, phase coding and echo hiding. It involves hiding data in audio files. This method hides the data in WAV, AU and MP3 sound files. There are different methods of audio steganography. These methods are i) Low Bit Encoding ii) Phase Coding iii) Spread Spectrum.
• Video-based