Have you ever tried to send a confidential message without letting anyone know that you did? or have you ever heard of the concept of hiding something in plain sight? If you have not, there exists an age-old art that thrives in the shadows, an art known as steganography.
In this article, we will delve into the concept of steganography, including what it is, the mechanism behind it, its types, and its involvement in today’s digital world.
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Steganography in today’s digital world
What is steganography?
The word “steganography” originates from the Greek word “steganographia”, a combination of steganós, signifying “hidden or veiled,” and graphia, meaning “writing”. According to Wikipedia, steganography is the practice of concealing information within another message or physical object in a way that obscures it from human inspection. This practice is not a novelty, as it has been used for centuries all over the world under different governments.
In ancient times, steganography was primarily a physical practice and the earliest documented instances of its use date back to 440 BC when the Greek historian Herodotus recorded two examples in his work ‘Histories.’
One of these examples involved Histiaeus, the ruler of Miletus, who marked the message he intended to send to his son-in-law Aristagoras, on the shaved head of his most trusted servant. After the servant’s hair had grown, Histiaeus sent him to Aristagoras, who then shaved the servant’s head to reveal the message.
Today, steganography has transitioned into the digital realm and can be employed to hide text, images, videos, and audio data.
How does steganography work?
Steganography works by concealing the fact that a message has been sent. The most popular steganographic approach is called ‘least significant bit’ (LSB), and this technique involves the insertion of the secret message into the least significant bit of a media file.
For instance, imagine you have an image represented in binary (zeros & ones), where each pixel is made up of three-color channels: red, green, and blue (RGB). Each of these color channels is typically represented by 8 bits, so you have 24 bits in total for each pixel.
LSB steganography replaces the least significant bit (the right-most bit) of each color channel with a bit from your secret message. Since the least significant bit is the one that has the least impact on the overall color of the pixel, altering it slightly is less likely to be visually detectable.
Types of steganography
- Text steganography: This type of steganography involves hiding data in text files to conceal a message. It can be implemented in different ways such as hiding information within the whitespace characters (spaces, tabs, line breaks) of a text document or hiding information by using different fonts, font sizes, or text styles (bold, italic, underline) to represent bits of the secret message.
2. Image steganography: It involves embedding secret data within the pixels of an image file by subtly modifying the color values of individual pixels or altering certain patterns within the image. In doing so, the image appears unchanged to casual observers. In simpler words, this technique conceals data by using an image of a different object as a cover.
Key components of image steganography:
- Cover Image: This is the original image (carrier) used to hide the secret data and it remains unchanged in appearance.
- Secret message: The information or data that you want to mask within the image. It could be text, another image, or any type of binary data.
- Steganography Algorithm: It is used to embed the secret data into the cover image. Ex: Least Significant Bit (LSB) insertion
- Steganography Key: It is required to embed and extract the hidden data. It also ensures that only authorized individuals have access to the hidden data.
3. Audio steganography: It is a technique used to hide secret or confidential information within an audio signal, without altering the perceptual quality of the audio. A common technique is called Backmasking and it requires the intended receiver to play the audio backwards to retrieve the hidden message.
4. Video steganography: It is a more sophisticated version of image steganography that encodes chunks of secret information inside video sequences. Digital watermarking is a popular method of video steganography and it is primarily used in the entertainment industry to protect copyrights and trace unauthorized distribution.
5. Network or Protocol steganography: it is a technique that uses common network protocols (TCP, UDP, ICMP) to hide a secret message. For example, data could be hidden in the header field or payload field of a network packet.
Steganography in today’s digital world
Modern technology has taken steganography to new heights, and it can be used for both legitimate and malicious intent. For example, professional photographers often use steganography to embed their copyright information (such as their name or website URL) into their images. This hidden information can help prove ownership if someone tries to use the image without their permission.
On the other hand, a threat actor could distribute a malicious piece of software, such as a trojan, to a target’s computer by embedding the malicious code within an image file like a JPEG, using steganographic techniques.
Conclusion
As we’ve explored throughout this article, steganography has a rich history dating back centuries, but its relevance remains undiminished in the digital age. It serves as a testament to the enduring human drive to protect secrets or exploit vulnerabilities.
Resources
Secrets Hidden in Images -https://www.youtube.com/watch?v=TWEXCYQKyDc&list=LL&index=2&t=76s
LSB Steganography Demo — https://www.youtube.com/watch?v=yNo58UiIMKU&list=LL&index=1
Introduction to Steganography — https://www.youtube.com/watch?v=GPdIY6ObKJU
