Classic assumption attack. Assumption: ink on paper is permanent, and can be trusted to ensure bags of money end up with the right person. Attack: use ink that isn’t.
Defenses: Have your bookkeeper use a Sharpie. Chemically or physically test the inks. Or, best yet, make the system closed-loop by adding feedback — check the data coming back from the bank.
Lifehacking– forgot to mention earlier that unsliced bread seems to have much more positive effects than the presliced stuff. (I assume due to nutrients evaporating between the slices, but who knows.)
a) An addenda to my previous note: feel free to distribute all my original research (like the Neurophone stuff) posted here however you like, as long as you don’t say where you got it. Call it CC-NOBY 😉
b) More results from playing with the thing:
The Neurophone electrodes put a ton of electrical signal into the surrounding tissue. Using a completely isolated (battery powered) scope and high-impedance preamp to probe the skin area around the electrodes, I picked up square-wave signals as high as 100mV (very roughly estimated) several centimeters away from the transducers. There is likely an RF-interference component too, as the electrodes/transducers are connected to the Neurophone with unshielded leads.
I confirmed that in Neurophone-only mode, there’s no way I’m hearing the sounds from the transducers with earplugs in through the air… the transducers aren’t audible holding them right near my ears with my ears plugged.
Using it in Neurophone-only mode (transducers placed far from head) and listening to music through earplug-style headphones, something weird happens. The apparent volume of the Neurophone signal is INDEPENDENT of the music volume. This mostly happens with music that doesn’t have a ‘noisy’ high end, like classical music.
Blasting Rammstein’s “Haifisch,” on the other hand, significantly masked the Neurophone signal during periods where the song had lots of high-frequency content. The same applied to other rock songs (especially with cymbal solos…). It’s possible this effect would be more significant with headphones that had higher-frequency response, but my Etymotic ER-4S are among the few things that have been stolen from me in my travels.
Near the spine makes a superb location for placing the Neurophone transducers, for some reason.
The Neurophone design as posted actually needs an 8th gain stage — a preamp to amplify the audio signal. In Neurophone-only modde I managed to get something halfway recognizable as music by putting (yet another) opamp between my MP3 player and the Neurophone input. In bone-conduction/Neurophone mode, I achieved better than open-air fidelity by placing the transducers against my jaw.
Unlike the original Neurophone (which transmitted the signal to the nervous system through an electric field, turning the nervous system into a radio receiver), this one definitely operates mechanically. I found using one transducer (with the brass substrate plate connected to ground) nearly as effective as two (with voltage travelling between them).
“Fraud comes in all sizes. In late February, a former Bear, Stearns & Co. secretary pleaded guilty to using disappearing ink to make more than $800,000 fade from her boss’s bank accounts, according to an Associated Press report. Anamarie Giambrone used the trick pen to write checks for senior managing director Eli Wachtel. After the checks were signed, Giambrone would erase the name of the payee and rewrite them for cash.
Using erasable ink is a very common fraud technique used by bookkeepers in small companies, says Gary Zeune, president of The Pros and The Cons, a Columbus, Ohio-based speakers bureau for white-collar criminals. It works because the bookkeeper figures out that management never looks at the bank statement. That’s “a big mistake,” cautions Zeune, who says eyeing bank statements is a standard internal-control procedure.”