The ecash solutions use serial numbers Money spent have thei

The e-cash solutions use serial numbers. Money spent have their serial number recorded, in order to prevent double spending. Remember that when withdrawing the money, Bob the payer, needs to create multiple copies of the money he wants to withdraw. All the copies are for the same currency level (e.g, 20 dollars) but have a different serial number. Why are the serial number used in the copies, unique? show what happens if Bob inadvertently create two copies of the money with the same serial number

Solution

Answer

The serial number used in the copies are kept unique for security purposes so as to prevent forgery, tampering and counterfeiting.

If Bob inadvertently create two copies of the money with the same serial number then following will happen:
i. money is checked before it is sent out for circulation, the same serial number will be caught then
ii. such money will be made invalid and will be kept aside as counterfeit money