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[Question] Steganography

[WolverineFan]

Re: [Question] Steganography

[Sasuntsi Davit]

in the press release it said some messages are hidden in microscopic text on the cards, like the stamp thing in "Paycheck".

[tanner]

i've got a very powerful micro-fiche reader -- but it needs transparencies

[BrianEnigma]

[rose]

more questions

[WolverineFan]

Re: more questions

[BrianEnigma]

Re: more questions

[WolverineFan]

Fixed the scanner. No, 600 dpi isn't fine enough to read the microtext signature line on a cheque. That stereoptic microscope is sounding good now

[colin]

I've read the micro text they use on australian notes using a scanner...but i can also managne to read it by looking at it closely...so maybe you guys are talking about something even smaller

[iwozframed]

ok i dont know if this is any help but all three of my silver cards
(240, 243 + 244) have started to warp
the longest edges are curling up (card face up)

yeah, yeah.... mistreating.... blah blah

but no they have been treated no different from the others, in fact prob better as i leave them stacked(red top, silver bottom) so they're held flat every night!
i can only spec that this is something to do with the coating on the top of these cards, and therefore are all coated the same.

[WolverineFan]

[Scott]

Have you tried eating them?

[Seej]

It's possible that the foil edges could be use to holographically embed data, but looking at the three that I have (Elucidate, Syzygy cube, T-L-P) there doesn't seem to be anything there. I would expect the reflective bits to have some sort of pattern (aside from the stars or whatever).

As for ways to hide data, it's instructive to think of security measures of banknotes, which could be equally used to hide information. On all British notes we have the following:

• Microtext
  
• Watermarks
  
• Careful colour variation (incidentally, some of my high-school qualification certificates used this, or pattern variations to make hidden text like "COPY" appear if they were photocopied)
  
• Holograms
  
• Raised ink
  
• Metal security thread woven through the note (on US notes this is plastic, hidden inside the note and only visible when held up to the light, and has writing in it IIRC)
  
• UV text (the denomination of the note)
  
• Special paper that's difficult to reproduce and feels different to normal paper
  
• Intricate patterns that produce Moiré patterns if copied.
  

We've definitely seen one of these, so it's reasonable to suppose that we might see others.

Another method could be invisible ink. I'm sure we all know about lemon juice (heat to reveal) but you could also use corn starch, and use iodine to hide/reveal the message. The only problem with this is that iodine turns dark blue/black on contact with any starch, such as the paper the card is made of, so the card would need some sort of water-resistant surface (which, obviously, would feel different) and you'd need to find someone brave enough to risk damaging their card(s). A baking soda solution would also produce invisible ink that reacts to heat, but you could also use an indicator (e.g. grape juice) to show where the alkaline areas of the card (i.e. the text) are. Other, less common chemicals such as phenolphthalein (colourless below about pH 9, goes pink above it, could be developed with a baking soda solution) could also be used. Incidentally, Scott, if they have used phenolphthalein you definitely don't want to eat the card

[MarcB]

I definitely think a card to look for steganography on is #184 - Love letters. There's so much empty space for a message to be hidden. Maybe try lemon juice?