Data Hiding: Exposing Concealed Data in Multimedia, Operating Systems, Mobile Devices and Network Protocols; Michael T. Raggo, Chet Hosmer, found via ; Michael T. Raggo, Chet Hosmer, found via ELU Stack Exchange

Metal Detector

Threshing

Fire

Magnet

Child Labor

Centrifuge

X-ray Machine

Breeze

Water

Fat Chick

Microbial Action + Time

Hydrochloric Acid

Guinea Pigs

Ground Penetrating Radar

Photoacoustic Imaging

Spotlight

Dear Needles Hiding in Haystacks,I will find you.People have been trying to find needles in haystacks for quite some time now (or needles in bottles of hay as the case may be) with what would appear to be a very high failure rate, because the metaphor still stands after all these years as a prime example of a near-impossible task.The thing is, finding a needle in a haystack doesn't sound difficult. It isn't a near-impossible task and Dr. Neil Johnson was right to step in there and publicly humiliate the chucklefuck who wrote this book, because the idea of a practitioner of the black arts of steganography not being able to think of a way to find a piece of metal surrounded by biomass is an embarrassment to the entire field. The superior intellects across the street at the cryptography convention must have been chortling into their limited edition Alan Turing ascots.I cannot be the first person who's mused about ways in which a needle could be extricated from a loose pile of dried grass. I haven't looked to see what other armchair philosophers have come up with, and I refuse to look because God damn it, I want to compose my own list and feel the warm sunlight of originality glowing on my cheeks for a few minutes before the internet comes rushing in and ruins it.For the purposes of this thought experiment I will assume that the missing needle in question is composed of steel and not some other material such as bone, brass, plastic, or wood, although many of these techniques would also work for the latter materials.- Let's start with the most obvious answer. Less than $50 and a couple 9-volt batteries put you in business. Sweep the stack for a couple minutes. The most work you'd have to do is spreading the hay out so you can get the metal detector within range.- As long as you're spreading the hay out anyway, you might as well keep tossing. The needle's higher density guarantees that it will eventually end up at the very bottom, glittering up at you from the floor. No batteries required.- You'd think those enlightenment thinkers would have thought of this. Torch the grass and what's left? Success and a poorly thought-out metaphor.- Unlike the metal detector, this little trick could have been used even before electromagnetic fields were understood. It could take a while depending on the size of your magnet, but hey, you should have thought about that before you started sewing in the loft.- The good Lord knows this isn't my first time extolling the virtues of child labor , but you'd think it would have been extra obvious to people living in the 19th century. Not only are kids cheap, but their tiny fingers are particularly adept to sorting through roughage.- Once again we're utilizing steel's lower size-to-weight ratio here, but this technique would work on needles made from other materials as well, with a possible exception for needles made from carbon fiber, which I'm told actually exist - Really a no-brainer. It might be a chore renting a mobile unit and bringing it out to your farm, but once it's there, actually locating the needle shouldn't take more than a couple minutes. And then you have some scouting images of the grassy terrain in case the needle tries to make a run for it again in the future.- That's right. Finding a needle in a haystack is literally a breeze. Open the barn door on a windy day and watch as the breeze plucks away one blade after the next until only the needle remains.- Flood the barn with a garden hose and then open the door. The hay floats away leaving the needle behind. Not only that, but you also have a clean barn.- Invite your fat neighbor over for a roll in the hay. Bigger is better here, because it means more surface area and higher odds of success in a shorter time period. When she screams, you've found the needle... or the G-spot, or both.- This one will take a while, but it's pretty much effort-free. Ruminal microorganisms would make a great starter culture. Just make sure you're working with asteel needle before encouraging high-moisture bacterial growth over a long period of time.- This main ingredient of stomach acid is really good at breaking down organic compounds like hay; not quite as adept at metals, as any child who has eaten paperclips or batteries can attest. That doesn't mean that this technique doesn't require finesse however; there's still a fine line between dissolved hay and an unusable needle. Keep an eye on your haystack after spraying it down with diluted hyrdochloric acid, and swoop in with a pair of rubber gloves to claim your needle as soon as the surrounding hay has been "digested."- A small herd of guinea pigs doesn't cost much, and you can raise them yourself if need be. Lots of animals eat hay, but guinea pigs have tiny little mouths that won't accidentally swallow the needle. Also, the little squeaking noises they make are pretty cute.- The same technology that's made corpse-discovery a cinch can also be applied to needle detection! It's also more portable than the x-ray machine and includes none of that annoying ionizing radiation exposure. The small size of the needle would make hiring an experienced operator very important.- Encapsulate the haystack in photoacoustic gelatin. Then fire near-infrared laser pulses into the gelatinous mass. The needle will vibrate at a much higher frequency than the surrounding hay and this information can then be displayed as a visual image. Follow up with a PAI-guided biopsy to recover the needle from the gelatin-encapsulated haystack.- If nothing else occurs to you, you could always come out at night and sift through the haystack with a spotlight. This technique would also require digging through and spreading out the hay, but sooner or later your high-powered beam would catch the reflection of the needle.Ouch. Kind of embarrassing for the Needle in a Haystack metaphor. I guess not onlythere one, but indeed more than one way to skin a haystack . And many of them require laughably little effort.A big thank you to the Vintner over at The Stem Cellar for her advice, corrections, ideas, and help on this letter.Sincerely,Sebastian Braff