PIN sentry

[fredpuli47]

Barclays issue customers with a PIN sentry for online banking. The customer enters the last four digits of their debit card into this hand-held device, followed by their PIN. The device then generates an eight digit number which the customer enters on their computer. The computer recognizes this and allows the customer access to their account.
How does it work? How does the computer receive and, more importantly,know to recognize the device's generated 8 digit number as the correct number to access the account. Is their some wireless connection? Is it magic?

[factor-fiction]

I don't think there is any communication taking place through the device- I assume there is a chip in it which does a calculation/conversion, probably involving large prime numbers, and the chip and the system can identify valid numbers

[Count-A-Strong]

Question asked previously ( always a good idea to do a search before asking):
http://www.theanswerb...s/Question476217.html

[ABerrant]

http://en.wikipedia.o...uthentication_Program

[Hopkirk]

Sounds a bit like an Enigma machine

[Skids]

Dunno how it works but my NatWest card works in my Barclays card reader, and vice-versa.

[AlBags]

A methematical algorythym.
What's more .. any Pin Sentry will work with anyone else's account.

[lordmarshall2013]

The answer to this on going question that seems to be all over the internet is much simpler than and algeryhtem, but still very secure and hard to crack. The first time you place your cash card ina cash machine the banks issuer places apx 100 (6 digit) codes on your chip that is on your card, without you even knowing the codes. The first time you then place your card into the pin sentry, and after entering your pin number, the sentry picks (1) of the 100 (6 digit) codes from the chip on your card and then displays it on the screen. You then enter this number on the web, and it checks it to the main frame computer at the bank to check it matches to 1 of the 100 that was issued at the cash point. If this is correct, then it allows you in to the online banking. Once used it is dead, and you are left with 99 more codes. Eventually, once you start getting low on codes on the chip of the card, the cash point the next time you use it will issue another 100 to the chip, and it a cycle that cannot be hacked. Even taking the PIN SENTRY Apart will not give any secrets away, all it's doing is reading the chip on the card, which is why you can use anybody's reader. This is how it works without a internet connection. It gets the internet connection from the cashpoint, and then works offline, just like email clients. Very simple, but effective.

[anon_private]

I note from one of the posts states that the card has say 100 numbers installed by the Bank.

But how does the account know which of the generated numbers is correct, Could it not give a hacker 100 chances to gain access?

The PIN might be crackable.

The card might be cloned?