Presentation on theme: "Steganography and Network Security"— Presentation transcript:
1Steganography and Network Security BySravya Nagaraju
2Contents: Introduction Frame works Categories Image Steganography ApplicationsReferences
3INTRODUCTIONSteganography:Steganography is the art and science of writing hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message.
6Image Steganography:Image Steganography is the technique of hiding the data within the image in such a way that prevents the unintended user from the detection of the hidden messages or data.
7For Example Original image Stego Image Image sources: https://www.pushpraj.com/photos/cool-scenery
8Methods: Image Domain Least significant bit Substitution Pixel indicatorStego Color CycleMax BitPixel value Differencing
9Image Domain:Images are made up of lots of little dots called pixels. Each pixel is represented as 3 bytes – one for Red, one for Green and one for Blue.Each byte is interpreted as an integer number, which is how much of that color is used to make the final color of the pixel.= Orange Color
10The difference between two colors that differ by one bit in either one red, green or blue value is impossible detect for a human eye.So we can change the least significant (last) bit in a byte, we either add or subtract one or more values from the value it represents.This means we can overwrite the last bit in a byte without affecting the colors it appears to be.
11A common approach of hiding data within an image file is Least Significant Bit (LSB) Substitution. In this method, we can take the binary representation of the hidden data and overwrite the LSB of each byte within the cover image.
12Least significant bit Substitution: Suppose we have the following binary representation for the Cover Image.Suppose we want to "hide" the following 4 bits of data: 1011,we get the following,Where the each data bits are accommodated in the least significant bits of each byte of the image.
13Least Significant Bit Substitution results in a very minor distortion of the image which is very much negligible for the human eyes.Original ImageStego ImageImage source:
14Pixel Indicator:This method uses the least two significant bits of one of the channels to indicate existence of data in the other two channels.
15Stego Color Cycle:The SCC technique uses the RGB images to hide the data in different channels.It keeps cycling the hidden data between the Red, Green and Blue channels, utilizing one channel at a cycle time.
16Max Bit:This method measures the intensity of the pixel and then hides data by random pixel selection with a goal to hide maximum data in each pixel.This method is divided into three parts:EncryptionImage Intensity CalculationSteganography.
17Original Image Grayscale Image Intense Pixels All Black colored pixels are considered as Intense pixelsImage source:
18Pixel Value Differencing: Pixel Value Differencing (PVD) is able to provide a high quality stego image in spite of the high capacity of the concealed information.That is, the number of insertion bits is dependent on whether the pixel is an edge area or smooth area.In edge area the difference between the adjacent pixels is more, whereas in smooth area it is less.Smooth AreaEdge AreaWhile human perception is less sensitive to subtle changes in edge areas of a pixel, it is more sensitive to changes in the smooth areas
19Applications of Image Steganography Secure Private Files and Documents.Hide Passwords and Encryption Keys.Transport Highly Private Documents between International Governments.Transmit message/data without revealing the existence of available message.