Which steganography technique is used to create cover for secret communication?

• A. Substitution Techniques
• B. Transform Domain Techniques
• C. Cover Generation Techniques
• D. Spread Spectrum Techniques

Answer: (C)

In steganography, some methods focus on building the cover content itself to carry the secret message. Cover Generation Techniques, also known as synthesis-based approaches, create a cover object in a way that the payload is embedded within its very structure. Instead of taking an existing image or audio and hiding bits inside it, you generate the cover so that its data encodes the message from the start. This can help control the statistical properties of the cover and ensure the embedding aligns with the payload.

Substitution techniques embed by altering parts of an existing cover, such as replacing bits (for example, in the least significant bit) with payload bits. Transform domain techniques hide data in transformed coefficients (like DCT or wavelet domains) of a preexisting cover. Spread spectrum techniques disperse the payload across many frequencies or components to improve robustness, typically within an existing carrier.