how does a recharge voucher&coupon works

how does a recharge voucher works

hi friends today let us see the actual working of the recharge voucher works...............

Hello friends,

There is no complete verification o the method followed by the topmost companies which offers coupons such as recharge cards for commercial purpose or recharge.. But here is a method which is accepted globally by maximum number of people.

1. Permutation

2.hamming and security

3. VMC

 these are the key-steps for the management of the recharge vouchers.

In this process the recharge coupons were permutated for the year of manufacture, that means vouchers were made for once a year as they will be expired after one year. Then the nearly 10% of the coupons were made out the permutated coupons.

Now I will give a detailed mathematical explanation on the above steps and elaborate the steps completely

Consider a large country like India and a service provider like say some company "X"

1.permutation

The recharge voucher consists of 16 digits and it can be permutated such that it consists of

0-9 numbers with repetition..

Soo the total number of permutations is 9×10^15=90000000000000000=900, 000 billions or 9 lakh crores

Its clear now

comes to demand the total number of population is 1.4 billions  or 140 crores(approximately)

In an average every Indian needs 3 recharge voucher a week

So total vouchers used per year = 3× 52 Weeks×1.4 billions=218.4 billions

<<note:we calculate for year because every coupon expires after one year>>

So the chances of occupancy is (900000/218.4) =4,120

So the conclusion is for every 4, 120 coupons one will be selected

The way of selection is described below..

2.hamming and security

In the second phase the selected number of coupons were printed with a unique code

Which always exists with respect to the serial number of the code followed by a strong algorithm. In this case we use a concept called hamming distance the below example illustrates the concept of hamming..

Hamming means the changes made in the uniform manner between the length of the strings or another words change in string distance.

After the hamming process then the 12 digits of the voucher is supported by a 4 digit pass-code (since the total number of digits were 16)

The hamming distance is also applicable for them too..

For example consider two alternate  recharge vouchers

The card we have chosen is

Now consider the next voucher of alternate serial number 
In the above example

The difference between the two cards is highlighted

"1" indicated the hamming distance which was 2, 3 as the digits of that place were replaced.

"2" indicated the security code of the voucher..

3. VMS

The trickiest technique is vms (voucher management system)

A limited number of coupons were entered to the server or any working main frame system of the company for a limited time say one month in advance.. As the codes works with the serials which have entered in th vmc only works since the rest of them awaiting for their activation..

I think you dont need an example for this as all of you have experienced that sometimes your recharge voucher doesn't work and when you call your customer-care or service provider they asks your serial number and it works within a minute all this because of this vmc.

K now don't start trying to get free recharges because its very complicated now a days and also the providers increased security however you will be caught after some days,,

sai krishna