security//steganography

Steganography is the practice of concealing the existence of a message inside an ordinary-looking carrier. This differs from cryptography, which conceals meaning while usually making the existence of ciphertext obvious.

Steganography is the practice of concealing the existence of a message inside an ordinary-looking carrier. This differs from cryptography, which conceals meaning while usually making the existence of ciphertext obvious.

The LSB (least significant bit) technique hides a 1 by forcing the pixel's LSB to 1 and a 0 by forcing it to 0, whatever the original pixel value.

A red channel of 142 (10001110) that must hide a 1 has an LSB of 0, which flips to 1 and gives 143 (10001111). To hide a 0, the LSB already matches and nothing changes.

A one-level channel change is generally imperceptible in isolation, but large payloads can introduce statistical patterns detectable without seeing the message.

Naive LSB encoding is fragile: resizing, color conversion, filtering, or lossy recompression can destroy it. Robust schemes instead hide information in transformations or features expected to survive the channel.

The security failure is assuming invisible means undetectable. Steganalysis looks for distributional evidence, not a pixel that appears suspicious to a human.