[HN Gopher] Hide a photo inside another photo ___________________________________________________________________ Hide a photo inside another photo Author : avestura Score : 28 points Date : 2022-04-28 20:35 UTC (2 hours ago) (HTM) web link (www.avestura.dev) (TXT) w3m dump (www.avestura.dev) | 1970-01-01 wrote: | Check out https://en.m.wikipedia.org/wiki/Steganography if this | is your thing | dennis-tra wrote: | Steganography is a very exciting topic and is not limited to | image data but can also be applied to, e.g., audio data. | | I've done something similar in the past and embedded Merkle tree | nodes in an image to allow partial integrity validation. It was a | fun little project: | | https://github.com/dennis-tra/image-stego | gregorymichael wrote: | "A picture of you, holding a picture of me, in the pocket of my | blue jeans." | noasaservice wrote: | Hmm. | | So combined with Apple's CSAM scanner, you can put CSAM inside a | cat photo... And then anonymously leak the cat photo and tool to | show it's CSAM. And then the CSAM scanner will flag the hash and | alert the police of the user. | | And the target victim would never know. | woodruffw wrote: | This is substantially more complicated than finding a collision | against the perceptual/"content aware" hash that Apple was | planning on using. | japhib wrote: | This is how PICO-8 game cartridges are contained in a small PNG | of the game itself! | | https://www.lexaloffle.com/pico-8.php | | https://robertovaccari.com/blog/2021_01_03_stegano_pico8/ | dividuum wrote: | Interesting. I always thought they'd use some PNG chunk | (comment?) for that. | jstanley wrote: | Ages ago I made a tool that does a similar method (rewrite the | least-significant N bits of a pixel in the cover image with the | most-significant N bits of the corresponding pixel of the hidden | image). In my tool N is configurable. | | The main pitfall is that it doesn't work very well if the output | is saved as a JPEG because of the compression. | | I think OP's idea of encoding _all_ of the bits of the hidden | image, by using a cover image with more pixels, is a good | improvement: you get no loss of quality in the hidden image, and | you vastly reduce the loss of quality in the cover image. | | https://incoherency.co.uk/image-steganography/ | pmoriarty wrote: | Videos provide much more space to hide data in than your typical | images do. | | I've always wondered if there was some way that hidden | information inside videos could be designed to survive the re- | encoding that youtube does when you upload a video. | | Has anyone investigated this? ___________________________________________________________________ (page generated 2022-04-28 23:00 UTC)