6 ms·

Took me a bit to understand, courier doesn't have the bill, the drop does. Boss: "Courier, deliver this money to <address>, code is 12345678" Courier: at <addr

Took me a bit to understand, courier doesn't have the bill, the drop does. Boss: "Courier, deliver this money to <address>, code is 12345678" Courier: at <address>, "Hey Drop, what is the code?" Drop: "Code is 12345678" Courier: "That's correct, Here's you're money" Drop: Tears bill in half and hands part with serial number to Courier as proof

cpeterso 7y ago
Why would the Drop need to retain half the serial number? They have received the goods.
- yesbabyyes 7y ago
  I'm not sure the drop retains half the serial number? GP claims the drop rips the bill in half, and hands the part with the (full, I seem to recall US dollar bills have the serial number on the bottom left) serial number to the courier. The courier can prove they delivered to the right drop, and the bill being ripped in half will ensure it won't be used again.
  - RaceWon 7y ago
    > I seem to recall US dollar bills have the serial number on the bottom left Our money (US Currency) has two (of the same) serial numbers on each bill; one on the lower left and one on the upper right for dollar bills. Other denominations also have two; one on each side of the front of the bill, however they are in opposite places i.e. upper left, and lower right--at least the current bills in my wallet are that way.
- bartwe 7y ago
  Ensuring the code isn't reused, to put in a ledger, to avoid some kind of replay attack, having someone pretend to be the courier and get the key to then replay to the real courier. Dunno, probably many many things avoided by making the key not usable but still verifiable.
  - qrbLPHiKpiux 7y ago
    Very important to never reuse a code, or one time pad. Perfect forward secrecy.
  - trickstra 7y ago
    I can think of only one scenario when it would make sense to destroy the bill - if the Drop is still able to present the whole bill after the Courier says they delivered the package, that is a proof the Courier is lying or got played and didn't verify the code. Drop is the one who has motivation to keep the bill intact, Courier uses the bill as proof of delivery, and cuts it in half just to be safe that someone from the Drop won't stop them at gunpoint after the delivery, stealing the whole bill.
- p1mrx 7y ago
  Well, the Drop can take the bills back to the bank. "The corners fell off. Can I have some fresh ones?"
  - steevdave 7y ago
    But they can't use that specific one again, it doesn't matter if they take the bill to a bank and get new ones, because the serial numbers won't be the same.
  - inlined 7y ago
    I doubt a Drop cares enough about $1 to repeatedly engage in suspicious behavior with a bank
    - p1mrx 7y ago
      That's the joke.
- afiori 7y ago
  In a criminal organization security and accountability are a more complex topic, but I would say that this way the one serial number the drop keep is a proof of identity, while the serial number the courier keep is a receipt.
rohan_shah 7y ago
Yes you're right. It's called "havala" in India and is common among traders of all goods. People do this because having more than ~3000$ cash (in Rupees) is illegal, but people use it anyway. So I can tell you that the Drop has the note. And yes, here the whole note (bill) is given to the courier by Drop as receipt, not by tearing in half. And I don't think even there people tear the serial number into half. Just the note.
- Razengan 7y ago
  > People do this because having more than ~3000$ cash (in Rupees) is illegal Wait, really? Do you mean no one is allowed to keep that much money in a safe in their house etc., or what? Why?
  - Bograff 7y ago
    I'm not up to date on the issue but India had an issue with black money and people hoarding cash without reporting the income. The laws were passed to combat that IIRC.
  - caymanjim 7y ago
    Is this really that surprising? Having more than roughly $10,000 cash in the US is nearly illegal, in that you're guilty until proven innocent and the police can just take it until you prove that it was obtained legally. You may not be charged with a crime, but you're still going to lose the money. The courts are slowly inching away from this unconstitutional insanity, but a duffel bag of cash is still going to end up turning into a new Hummer for whatever local police squad finds it.
    - heelix 7y ago
      Hah. So years back, I was going to buy a car. Went to the bank and they wanted (what I considered to be) a ridiculous service fee for a cashiers check. Fine... I'll take cash from my account! Ah, need a couple days to do that sort of thing... I, was miffed and stubborn as hell... so I did just that. Came back, got fingerprinted, and picked up my pile of cash to go buy the two year old 996. The dealership, when time came to close, absolutely freaked when I pulled out the cash. Another set of IRS forms... and sorted it after several phone calls.

cpeterso 7y ago

Why would the Drop need to retain half the serial number? They have received the goods.

yesbabyyes 7y ago
I'm not sure the drop retains half the serial number? GP claims the drop rips the bill in half, and hands the part with the (full, I seem to recall US dollar bills have the serial number on the bottom left) serial number to the courier. The courier can prove they delivered to the right drop, and the bill being ripped in half will ensure it won't be used again.
- RaceWon 7y ago
  > I seem to recall US dollar bills have the serial number on the bottom left Our money (US Currency) has two (of the same) serial numbers on each bill; one on the lower left and one on the upper right for dollar bills. Other denominations also have two; one on each side of the front of the bill, however they are in opposite places i.e. upper left, and lower right--at least the current bills in my wallet are that way.
bartwe 7y ago
Ensuring the code isn't reused, to put in a ledger, to avoid some kind of replay attack, having someone pretend to be the courier and get the key to then replay to the real courier. Dunno, probably many many things avoided by making the key not usable but still verifiable.
- qrbLPHiKpiux 7y ago
  Very important to never reuse a code, or one time pad. Perfect forward secrecy.
- trickstra 7y ago
  I can think of only one scenario when it would make sense to destroy the bill - if the Drop is still able to present the whole bill after the Courier says they delivered the package, that is a proof the Courier is lying or got played and didn't verify the code. Drop is the one who has motivation to keep the bill intact, Courier uses the bill as proof of delivery, and cuts it in half just to be safe that someone from the Drop won't stop them at gunpoint after the delivery, stealing the whole bill.
p1mrx 7y ago
Well, the Drop can take the bills back to the bank. "The corners fell off. Can I have some fresh ones?"
- steevdave 7y ago
  But they can't use that specific one again, it doesn't matter if they take the bill to a bank and get new ones, because the serial numbers won't be the same.
- inlined 7y ago
  I doubt a Drop cares enough about $1 to repeatedly engage in suspicious behavior with a bank
  - p1mrx 7y ago
    That's the joke.
afiori 7y ago
In a criminal organization security and accountability are a more complex topic, but I would say that this way the one serial number the drop keep is a proof of identity, while the serial number the courier keep is a receipt.

rohan_shah 7y ago

Yes you're right. It's called "havala" in India and is common among traders of all goods. People do this because having more than ~3000$ cash (in Rupees) is illegal, but people use it anyway. So I can tell you that the Drop has the note. And yes, here the whole note (bill) is given to the courier by Drop as receipt, not by tearing in half. And I don't think even there people tear the serial number into half. Just the note.

Razengan 7y ago
> People do this because having more than ~3000$ cash (in Rupees) is illegal Wait, really? Do you mean no one is allowed to keep that much money in a safe in their house etc., or what? Why?
- Bograff 7y ago
  I'm not up to date on the issue but India had an issue with black money and people hoarding cash without reporting the income. The laws were passed to combat that IIRC.
- caymanjim 7y ago
  Is this really that surprising? Having more than roughly $10,000 cash in the US is nearly illegal, in that you're guilty until proven innocent and the police can just take it until you prove that it was obtained legally. You may not be charged with a crime, but you're still going to lose the money. The courts are slowly inching away from this unconstitutional insanity, but a duffel bag of cash is still going to end up turning into a new Hummer for whatever local police squad finds it.
  - heelix 7y ago
    Hah. So years back, I was going to buy a car. Went to the bank and they wanted (what I considered to be) a ridiculous service fee for a cashiers check. Fine... I'll take cash from my account! Ah, need a couple days to do that sort of thing... I, was miffed and stubborn as hell... so I did just that. Came back, got fingerprinted, and picked up my pile of cash to go buy the two year old 996. The dealership, when time came to close, absolutely freaked when I pulled out the cash. Another set of IRS forms... and sorted it after several phone calls.