Steganography - Types, Techniques, Examples & Applications

 

Steganography, or the need for hidden messages, is universal since everybody has something confidential. Though it is not such a familiar word as a virus, steganography is crucial since it deals with secrecy. Hiding or withholding information in a standard, national, personal, or family interest is an age-old practice. Cryptography similarly transforms plaintext messages into a jumbled algorithm for safety before sending. The receiver changes it back into plaintext. In Greek, steganography means ‘covered writing’ or ‘disguised messages,’ and nobody knows the hidden meaning.

                                    

Types:

• Text Steganography refers to various media, including text and audio, video, and images. Almost every media form uses text. Data compression through Huffman coding results in a smaller size.
• Image Steganography hides a message within the image. A cover image is a particular picture that carries a hidden message. A stego image conceals a message that remains secret during transmission. A key is used to embed the messages in the cover and stego images. Sometimes, the images themselves reveal the message.
• Audio messages can be secretly embedded digitally. Illegal copying of the audio will not be then possible. By watermarking, for instance, one message is superimposed upon another. Media like songs uses such a technique to prevent piracy.
• Video steganography can include a large volume of messages since it deals with both audio and video in addition to images. Data is embedded, or additional files are inserted inside the video file. DCT, or the Discrete cosine transform method, is often used in the process of hiding data in video images. File formats like H.264 and MP4, along with MPEG and AVI, are often used.
• Network Steganography uses protocols like TCP and UDP, ICMP, and IP in the task of hiding data as cover objects. Secret channels like OSI make use of such systems.

 Technological examples of steganographic disguise

 An image hidden within a video would be visible only while playing the video at a certain frame rate.

• A file header or metadata could contain the secret message
• In an RGB message, the message could be hidden in one of the red, green, or blue channels
• The primitive form of invisible ink also helps hide a written message very effectively
• Inserting text in a picture that is somehow disguised in terms of meaning
• Reverse recording an audio file message

 Applications:

Steganography has a range of applications across various fields, including:

1. Digital Watermarking: Embedding a watermark in digital media (like images or videos) to assert ownership, track distribution, or provide copyright protection. The watermark is usually designed to be imperceptible to the casual observer.
2. Secure Communication: Concealing secret messages within ordinary-looking files (such as images or audio) to facilitate covert communication. This can be used to evade detection by surveillance systems.
3. Data Integrity: Embedding checksums or hashes within files to ensure their integrity. This can help detect unauthorized changes or corruption.
4. Digital Rights Management (DRM): Incorporating hidden information in digital content to manage usage rights and prevent piracy. This ensures that content distribution adheres to licensing agreements.
5. Authentication: Using steganographic techniques to embed authentication tokens or digital signatures within files, adding a layer of security to verify the source and authenticity of the content.
6. File and Data Hiding: Concealing sensitive data within innocuous files or data streams to avoid detection or interception. This can be useful for protecting intellectual property or sensitive information.
7. Covert Operations: In intelligence and espionage, steganography can be used to secretly transmit information between operatives or to disguise communications.
8. Medical Imaging: Embedding patient information or diagnostic data within medical images for secure and discreet sharing between healthcare professionals.

Each application of steganography leverages the ability to hide information within other data in ways that are not immediately detectable, making it a versatile tool in various domains.

Advantages

1. Covert Communication: The primary benefit of steganography is its ability to hide the existence of a message, making it ideal for covert communication where discretion is essential.
2. Complement to Cryptography: When combined with cryptographic techniques, steganography enhances security by both hiding the existence and encrypting the content of the message.
3. Integrity Protection: It can help protect data integrity by embedding checksums or hashes within files to detect unauthorized alterations.
4. Watermarking: Steganography is widely used in digital watermarking to embed ownership information or copyright claims within digital media without noticeable alterations.
5. Data Concealment: It can be used to hide sensitive information within less sensitive data, reducing the risk of exposure during transmission or storage.

Disadvantages

1. Limited Capacity: The amount of data that can be hidden using steganography is often limited by the carrier medium's capacity, and hiding too much data can lead to noticeable distortions or quality degradation.
2. Vulnerability to Detection: Advanced detection methods, such as steganalysis, can potentially reveal the presence of hidden information, especially if the steganographic technique used is not robust.
3. Ethical and Legal Concerns: Steganography can be misused for illicit purposes, such as hiding malware or engaging in illegal activities, raising ethical and legal concerns.
4. Complexity in Implementation: Effective steganography requires careful implementation to avoid detection and to ensure that the hidden data is both secure and retrievable, which can be complex and resource-intensive.
5. Performance Impact: In some cases, embedding hidden data can affect the performance or quality of the carrier medium, such as image or audio files, making it less suitable for applications where quality is critical.

Overall, while steganography offers significant advantages for privacy and security, it also presents challenges and potential risks that need to be carefully managed.

Sources:

https://www.tutorialspoint.com/Steganography - Types, Techniques, Examples & Applications (tutorialspoint.com)

 

Prepared by:

Aravind S P    III –BCA    22UCA007

Co-ordinate Staff: Dr.J.M.Dhayashankar