Re: Photocopying money
It's the same chip that's used in vending machines to scan dollar bills.
To my knowledge, vending machines don't do optical recognition. They have a pair of photo-sensors, it's true, but these are used in conjunction with tractors only to measure the bill. Another sensor decodes the magnetic ink to determine validity and denomination. I saw this demonstrated recently on a PBS science program. Scott Collins | "Few people realize what tremendous power there | is in one of these things." -- Willy Wonka ......................|................................................ BUSINESS. voice:408.862.0540 fax:974.6094 collins@newton.apple.com Apple Computer, Inc. 5 Infinite Loop, MS 305-2B Cupertino, CA 95014 ....................................................................... PERSONAL. voice/fax:408.257.1746 1024:669687 catalyst@netcom.com
Scott writes:
To my knowledge, vending machines don't do optical recognition.
In Japan they do. Some banks recently got scammed by people putting photocopied Y10,000 ($100) bills into changers at the banks (getting 10 Y1,000 in return). They've now done a ROM upgrade on the machines. A cultural point: Japan is a very cash-oriented society, so nobody blinked twice when someone went up to the changing machine and plunked 10 or 20 bills into it.
"Robert J. Woodhead" <trebor@foretune.co.jp> wrote: In Japan they do. Some banks recently got scammed by people putting photocopied Y10,000 ($100) bills into changers at the banks (getting 10 Y1,000 in return). They've now done a ROM upgrade on the machines. Hmm... I wonder how many free cokes I could get with that method... hehe :) There used to be a vending machine here where you could push 2 different buttons at the same time and get two sodas for the price of one. When I lived in California, there was a pay phone where you could dial an 800 number and then dial another number and it would charge you as if you were still connected to the 800 number (free calls!!!) Oh man... some vending machine companies overlook the most obvious things... I guess it can happen to anybody (remember identify #9 and get 1000000 ep? :) Hmm... what does this have to do with cryptography?
(This is nostalgiaware - skip past it if you're only into messages about encryption) Matthew writes:
Oh man... some vending machine companies overlook the most obvious things... I guess it can happen to anybody (remember identify #9 and get 1000000 ep? :)
This is a reference to my game, Wizardry, an RPG that allowed each character to have 8 items in inventory. Alas, the code that checked for valid keypresses in the "identify item" section had an error: IF (ch>='1') _or_ (ch<='8') then id_item(player,ord(ch)-ord('0')); This allowed any key to be pressed, and ended up twiddling bits in the data structure. Pressing 9 gave you extra experience points. Someone once sent me a list of what _all_ the keys on an Apple II did. We deliberately left this bug in the PC version of the game as it had become part of the legend of the game. Not much to do with encryption, but Wizardry encrypted it's game strings with a simple system that nobody broke (I guess tracing p-code was too much trouble). It added X*the character position and Y*the line number+Z*the previous character, as I recall...
"Robert J. Woodhead" <trebor@foretune.co.jp> wrote:
Not much to do with encryption, but Wizardry encrypted it's game strings with a simple system that nobody broke (I guess tracing p-code was too much trouble). It added X*the character position and Y*the line number+Z*the previous character, as I recall...
Yeah, that worked pretty well, considering that most people just looked for text by scanning it with a sector editor. Encrypting the text made it undistinguishable from the program code. Tracing the program code would have been difficult, considering that it was written in the original Apple pascal, which used a token compiler (I think). But, alas, the character files were in plaintext, and numerous people figured out how to edit them. So were the items and monsters. One day when I was very bored, I managed to decipher the maze data, and was then able to build a map of the 10th level where dumapic didn't work. As I recall, it was just 2 bits to define each section of wall, arranged in four groups of data defining each of the four directions, followed by another block of data which used nybbles to define what was found in the blocks created by the intersections of the walls. One thing that I was able to break was the code book that was the copy-protection for Return of Werdna. As I recall, it was calculated in base 9 (or some sort of nine number system which used the digits 1-9 but excluded zero). Once I realized that, breaking the code was just a matter of simple arithmetic. It was an interesting excercise in code-breaking tho, and I did it without disassembling the program. I must say that this was preferrable to the copy-protection in the original Wizardry, in which my master disk eventually wore out from overuse and developed bad sectors. Gee...All this nostalgia has made me want to play again. It's a fun game, and the 3-D system was pretty innovative for the time. Does Sir-Tech still replace bad disks (from the Apple II version)?
participants (3)
-
catalyst＠netcom.com -
Matthew J Ghio -
Robert J. Woodhead