Victor wants to send an encrypted message to his friend. He is using certain steganography technique to accomplish this task. He takes a cover object and changes it accordingly to hide information…

In the distortion technique, the sender deliberately alters properties of a cover object - such as pixel values in an image - to encode the secret message as a set of differences from the original. Extraction requires possession of the original unmodified cover, which acts as a key when differenced against the distorted version. This dependency on the original cover for recovery is the defining characteristic that distinguishes the distortion technique from all other steganographic methods.

The substitution technique replaces redundant or least-significant bits in the cover object with secret data and does not require the original cover for extraction.

Cover generation techniques create a brand-new cover object specifically designed to carry the hidden message, rather than modifying an existing one.

Spread spectrum steganography distributes hidden data across a wide frequency range within the cover medium using a spreading code, which is a fundamentally different embedding approach than distortion comparison.