In today’s security-conscious world, the concept of hiding something in plain sight has become increasingly relevant. The need to stay ahead of hackers and data thieves has led to the exploration of new techniques for protecting sensitive information.
One such technique is steganography, which involves hiding a message within another message or image. In this discussion, we will define what steganography is, examine the techniques used, and explore how it is used in current cybersecurity efforts.
What is Steganography?
What is Steganography? Steganography or Steganography is a science, technique, or art of hiding a secret message in a way so that the sender and the recipient of the secret message will only know the message.
Steganography comes from the Greek, namely Stegano, which means “hidden or hiding,” and graph, which means “Writing, so Steganography is writing or messages that are hidden.
Steganography is the opposite of cryptography which disguises the meaning of a secret message but does not hide that a message exists.
The advantages of Steganography compared to Cryptography are that the messages are inconspicuous and do not arouse suspicion, in contrast to Cryptography, where the message is not hidden, even though the message is difficult to decipher, it will raise suspicion of the message.
Types of Steganography
1. Injections
It is a technique of embedding secret messages directly in a medium. The drawback of this technique is that the injected media will become more significant than its standard size, so it is easily detected. This technique is also called embedding.
2. Substitutions
This technique changes average data into personal data. The result of this technique usually will keep the original data size the same but depends on the data to be hidden. This technique will reduce the quality of the media loaded.
3. Domain Transformation
This technique is very effective. The domain transformation hides data in the transform space.
4. Spread Spectrum
It is a transmission technique using a pseudo-noise code, independent of the information data as a waveform modulator, to spread the signal energy in a communication path (bandwidth) more significantly than the information communication signal. The receiver collects the signal again using a synchronized pseudo-noise code replica.
5. Statistical Method
This technique is also called a 1-bit steganographic scheme. The scheme embeds one bit of information on the media ride and changes the statistics, even if only by 1 bit.
Statistical changes are shown with an indication of 1; if no difference exists, a sign of 0 is shown. This system works based on the recipient’s ability to distinguish between modified and unmodified information.
6. Distortions
This technique creates changes to objects that are hosted by private data.
7. Cover Generation
This technique is unique to the other methods because the cover object is chosen to hide the message.
Stenography Purposes
The purpose of steganography is to hide the existence of a hidden message or information.
In practice, most letters are hidden by making subtle changes to other digital data whose content would not attract the attention of potential attackers, for example, an image that looks harmless.
This change depends on the key (same in cryptography) and the message to be hidden. The person receiving the image can then infer the hidden information by substituting the correct key into the algorithm used.
Stenography vs Cryptography
Steganography and cryptography both aim to protect messages and data from unauthorized access. However, they use different methods to achieve this.
Cryptography involves converting information into unreadable ciphertext, which is easily recognizable as encrypted. Steganography, on the other hand, hides a message within another message or image in its original format, making it difficult to detect.
Factors |
Steganography |
Cryptography |
|---|---|---|
| Explanation | It’s a method to conceal the fact that communication is taking place | It’s a method for making information unintelligible |
| Aim | Maintain communication security | Enable data protection |
| Key | Optional, but increases security when utilized | Necessary prerequisite |
| Data Visibility | No | Yes |
| Failure | Once hidden information is decoded, the data can be used by anyone | You can recover the original message from the ciphertext if you can access the decryption key |
| Data Structure | Does not modify the data’s general structure | Modifies the overall data structure |
Stenography Techniques
1. Substitution System Technique
Steganography uses a substitution system to replace redundant bits or bits not needed from the cover data with bits from the secret message.
One of the steganographic methods used is LSB (Least Significant Bit). However, there are drawbacks to the method of hiding messages using this substitution, namely the weakness of image-to-image processing.
Suppose the image is cropped or other image processing is performed. In that case, the algorithm cannot distinguish which bits are the least significant bits that are part of the message and which are the bits of the cover data.
2. Transform Domain Techniques
Basically, the transform domain technique hides the message within the “transform space” of a signal. Every day on the internet, people send picures to one another, and most often, they use the JPEG format.
JPEG is exciting because it will be compressed when closed. For this to happen, they have to get rid of excess data and extra bits that prevent them from compressing.
During compression, JPEG will make approximations of itself to be smaller, those changes and approximations are changing space, and those changes can be used to hide information.
3. Spread Spectrum Technique
This spread spectrum technique is divided into two, namely:
- Direct Sequence
In this method, the stream of information is transmitted into several small parts. Each portion is allocated to a channel frequency of the spectrum.
- Frequency Hopping
This technique divides the bandwidth spectrum into as many broadcast frequencies as possible. In general, frequency-hopping equipment uses less power and is less expensive but performs better in direct sequence systems.
4. Statistical method technique
This statistical method uses what is known as a “1-bit” steganographic scheme. This scheme inserts only one bit of information in a digital container and then makes even a tiny statistical change.
5. Distortion technique
This steganography method makes changes in the cover data to hide the information. Secret messages are recovered when an algorithm compares the differences between the distorted cover and the original.
6. Cover Generation Technique
This is the most unique compared to the other six types of techniques. Usually, cover data is used to embed a message within it. Still, this technique is different from what this technique does.
This cover generation method creates cover data with the primary goal of hiding the message. Spam Mimic is an excellent example of a cover generation method.