Steganography is derived from two Greek words:'stegos,' which means 'to cover,' and 'grayfia,' which means 'writing,' thus translating to 'covered writing,' or 'hidden writing.' Steganography is a method of concealing sensitive information by embedding it in an audio, video, image, or text file. It is one of the techniques used to protect confidential or sensitive data from malicious attacks.
What distinguishes it from cryptography?
Cryptography and steganography are both methods for concealing or protecting sensitive information. They differ in that cryptography makes the data unreadable or conceals the meaning of the data, whereas steganography conceals the existence of the data.
Cryptography is analogous to writing a letter in a secret language: people can read it but won't understand what it means. The existence of a (likely secret) message, on the other hand, would be obvious to anyone who sees the letter, and if someone knows or figures out your secret language, your message can be easily read.
If you used steganography in the same situation, you would conceal the letter inside a pair of socks that you would give to the intended recipient. To those who are unaware of the message, your gift appears to be nothing more than the socks. However, the intended recipient is aware of what to look for and discovers the message hidden within them.
Cryptography is frequently used to augment the security provided by steganography. Encryption algorithms are used to encrypt secret data before it is embedded in cover files.
Image Steganography -
Image Steganography, as the name implies, is the process of concealing data within an image file. The image chosen for this purpose is referred to as the cover image, and the image obtained after steganography is referred to as the stego image.
How does it work?
In memory, an image is represented as a N*M (for greyscale images) or N*M*3 (for colour images) matrix, with each entry representing the intensity value of a pixel. Image steganography embeds a message into an image by changing the values of some pixels chosen by an encryption algorithm.
Is steganography a safe way to communicate?
When steganography is used alone, it provides security through obscurity, which may result in the secret message being revealed. Combining steganography and cryptography is the most effective way to hide a message from adversaries while still protecting it if it is discovered.
What algorithm is used in steganography?
His steganography method involves hiding a large amount of data (image, audio, and text) within a colour bitmap (bmp) image. In his study, the image will be filtered and segmented, with bits replacement applied to the appropriate pixels. These pixels are chosen at random rather than in any particular order.
The process of steganalysis is used to detect the message within the cover image. This can be accomplished by comparing the image to the cover image, plotting histograms, or detecting noise. While efforts are being made to develop new algorithms that are more resistant to such attacks, efforts are also being made to improve existing algorithms for steganalysis, which detects the exchange of secret information between terrorists or criminal elements.