instant lottery cards too, Re: reading PINs in "secure" mailers without opening them

[Ed Gerck]

Years ago, I could read "instant win" lottery cards and still leave them
as new by using the laser photoacoustic effect. A low-power chopped laser
beam is focused and line-scans the target while a microphone picks up
the acoustic waves caused by differential absorption of the laser light
as it sweeps the line. By phase-shifting the received acoustic signal
versus the chopped light signal (they have the same frequency), you
can read at different depths of the target. Adjusting to hearing at
the depth of the paper substrate, below the covering ink, all markings
could be read as if the covering ink did not exist, line by line.

The apparatus could be built today by something like $500, I believe,
using parts readily available. Distributors of the "instant lottery"
cards could, without detection, separate the winning cards.

Unlike ATM cards, there are no cards that must be stolen at the same
time for the attack to be successful.

Cheers,
Ed Gerck

Perry E. Metzger wrote:
> Often, banks send people PINs for their accounts by printing them on
> tamper "secure" mailers. Some folks at Cambridge have discovered that
> it is easy to read the PINs without opening the seals...
> 
> http://news.bbc.co.uk/1/hi/technology/4183330.stm
> 

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