wow. you don't see the big picture here. What if you be the one to provide this kind of service to other people?
service==money

i wonder how this is implemented.
maybe using a binary flag, where 0=unlimited VIP, and normal card=1 ?
or maybe setting a variable to max value of 32 bit (roughly 2 billion).

if not mistaken, you need to provide IC to buy the card right ?
if so, then once the sync-reconcile fails, then the polis will come after whoever owns the card.

Actually Touch N Go does store the data on the card. You may tamper with the amount and use it few times until its detected and blocked.

I actually bought few cards (from LYN here) and eventually its blocked and asked for refund.

so how you tamper the amount?

the more important question is, what can we buy using touch n go ?
for example, is there any mall or retail outlet which accepts the card as payment for purchases ?

kk mart

1. Read the second paragraph. Which is my assumption, and gave the same meaning of 'sync'. When you do transaction, I doubt TnG terminals will directly connected to the server->check balance->then do transaction if balance is valid. Thus it's offline and transaction is allowed based on the balance stored in the card. End of the day, when clearance is done, the balance of the card might be calculated. Each transaction values will be deducted from the most recent top up value, a.k.a synchronizing. Thus, if final balance is negative, the card have invalid balance, meaning the data might have been altered by the user. I developed an e-payment system that uses smart card before. So I know how slow it would be if the transaction is online.
2. This one I know. I use this all the time when I top up my MyKad.
3. This one also I know. I did mention about APDU right? APDU is the way terminals/card reader communicate with the chip on the smart card.

May be.

I bought an RM 300 credit card for RM 100 before long time ago, used it only 2 times before it was blocked for further transaction.
Went to TnG centre and check, they said the card is faulty, they can issue a refund if I can find out the owner. (not sure if they will really issue a refund or report police instead)

Correct. Its actually offline for reload, and also when using the card.
At the end of the day then only it will all be sync back to TnG and that is when they detect the tampered amount.

Yeap.

I doubt it. High security means low performance.

The maximum limit set at RM 500..

u penah dengar tak laki bini kena tangkap sebab buat illegal tng topup

go hack their server.

there was once i reloaded my tng card in one of the bank atm, somehow the bank didnt deduct my money after i reload the card. true story!

Correct.
However both batch and real time transactions are performed, depending on the terminal's location.

Audited TnG before.

perhaps system has been upgraded by now to dealt the the loopholes, btw whats the max touch and go value can be stored? and how much is the max daily transaction?

Ok ur intelligent had surpass all criminal which never think anout tis b4