The attacker has access to the stego-object and the steganography tool or algorithm used to hide the message.

The attacker has access to the stego-object and the steganography tool or algorithm used to hide the message.

• A. Chose n-stego Attack
• B. Known-stego Attack
• C. zsteg
• D. Chosen-message Attack

Answer: (D)

In this scenario, the important idea is the attacker’s ability to influence what is hidden. A chosen-message attack means the attacker can pick the exact message to be embedded and then generate or observe the resulting stego-object using the embedding algorithm. With access to both the stego-object and the tool or algorithm, the attacker can experiment by choosing different messages and seeing how they appear inside the cover, which helps reveal patterns and weaknesses in the embedding method. If the attacker only had the stego-object and knew the method but couldn’t select the message to be embedded, that would be a different model. The option named after a tool is not about the attack model itself. So the correct choice reflects the ability to determine and inject a specific payload to study how it’s hidden.

In this scenario, the important idea is the attacker’s ability to influence what is hidden. A chosen-message attack means the attacker can pick the exact message to be embedded and then generate or observe the resulting stego-object using the embedding algorithm. With access to both the stego-object and the tool or algorithm, the attacker can experiment by choosing different messages and seeing how they appear inside the cover, which helps reveal patterns and weaknesses in the embedding method.

If the attacker only had the stego-object and knew the method but couldn’t select the message to be embedded, that would be a different model. The option named after a tool is not about the attack model itself. So the correct choice reflects the ability to determine and inject a specific payload to study how it’s hidden.