Plastic / Paper Token Verification

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At Video Games parlor or many other outlets I see people dispensing Plastic token. These token can be inserted into a machine which does a specific functionality. How are the plastic token verified. What sensor can do that? How do we build such a system? Can there be a paper token system also? How does a currency detector works?

 

Actually I want to design a system by which a paper token can be created and inserted into a device (not sure which one) but it would tell a detail of the paper token - say I have 3 paper token - pink, red, blue color or I am not sure what other way I can do that - if I insert the same in a device, it would tell me what had been inserted. Think of these paper token as cash dispense request of specific amounts.

 

What way I can design such a system without doing any online verification?

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Hello Prakash.

 

I suspect that what you have witnessed is the use of round RFID tags like these.

 

http://www.parallax.com/product/...

 

The game machine will read the tag's number and probably then check through a server what its "value" is, eg 3 games or just 1.

 

A paper based version could perhaps have a barcode printed, but I would not use it to dispense cash; too easy to copy/steal.

 

Cheers,

 

Ross

 

Ross McKenzie ValuSoft Melbourne Australia

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Thanks but my requirement is more like the token should be inserted into the device and be consumed for further use. There should not be any contact with server for processing.

 

Actually I am looking for a system that where a user just inserts a token and we dispense some item. If in case I have to online verification that would take time and investment to setup which I want to avoid.

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OK, so use the round RFID tag and have a list of all the valid tags. Do a local lookup to verify it is a valid token. You may be able to buy a sequence of tag numbers so that you just have to confirm that its number lies between the two valid ends.

Ross McKenzie ValuSoft Melbourne Australia

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Generally speaking:

 

1. Use a signing scheme, or some other "system of trust". (This might be e.g. a symmetric encrypting/signing scheme.)

2. Accepting machine, e.g. a vending machine, reads a signed token on the physical carrier. This token carries the value.

3. To prohibit reuse, the machine consumes the token.

4. To prohibit counterfeit tokens they must be hard to copy.

 

When Ross is talking about RFID stuff then this is a solution to, at least, #4. It is hard, but most likely not impossible, to copy an RFID tag.

 

------------

 

And now for something quite OT, but also quite related:

 

Incidentally, if you replace the symmetric key signing and instead have a paper token that is sufficiently hard to make trustworthy copies of, but still is recognized by the general public you have a solution that requires, in many circumstances, no electronics at all. You could e.g. print something quite elaborate on paper. You could use special features "internal" to the paper (watermarks, embedded thin metal strips etc). You could even print holograms.

 

The printing could include a value.

 

Now, imagine if you got a large part of the population to trust and use such tokens! Instead of shops having to have rather complicated equipment to read credit cards they could, in the simplest case, just accept such tokens and place them in a shoe-box under the counter! This would be a shop where you could buy things  even with no network available, and under total electrical blackout. Or take the case where you want to settle a debt to a friend of yours. Instead of getting your friends bank clearing- and account-number (extra hard in Nigeria, I've been told) you just pull out your stack of such tokens and hand over a collection whose summed up token value matches the amount of the debt.

 

Now your friend is in possession of those tokens and can use them in other such arrangements, settling a debt, or using the token directly at some occasion so that there never arises any debt.

 

You would never need to say "Yes, I could transfer that amount to you - but the batteries in my cell phone are dead so you'll just have to wait". This could be a source of much irritation.

 

Imagine the simplicity and generic nature of such a system. If everyone used the same system, then you would not be in the hands of the bank that issued your credit card! At least it should be feasible that everyone in the same country used the same system. Then it could be controlled not by private interests but by the government. Many judicial advantages would be available!

 

But, it will be just as usual. Whenever I get one of those brilliant ideas the world will not understand what a genius I am, and it will all come out to nothing. Admit, though, that it would be a slick solution if it ever happened!

 

[sorry - irresistible]

"He used to carry his guitar in a gunny sack, or sit beneath the tree by the railroad track. Oh the engineers would see him sitting in the shade, Strumming with the rhythm that the drivers made. People passing by, they would stop and say, "Oh, my, what that little country boy could play!" [Chuck Berry]

 

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