Barclays Pinsentry security device

david78

The pin is not stored on the card. Instead a special "hash" or code is derived from the pin and this "hash code" is stored. (e.g. search for MD5 hash). It is not possible to discover the pin number from the hash, but it is easy (in software) to check that a given pin matches the hash code.

I think when you make a purchase both the hash and pin are checked for compatibility, but i dont know whether this is done in the terminal or by the banks.

When you change the pin at an ATM a new hash is stored and saved on the chip in memory.

david78

CLAPTON wrote: »

all the pinsentrys are the same ..you can use Nationwide's pin sentry with your barclays debit card, or use your nationwide debit card in a tesco one etc etc..

Yes, they are all made by the same firm I believe. I bank with Nationwide and Natwest and use either card reader for both.

agsnu

david78 wrote: »

I think when you make a purchase both the hash and pin are checked for compatibility, but i dont know whether this is done in the terminal or by the banks.

Neither. It is done on the card, which basically generates an authentication code for the transaction.

agsnu

david78 wrote: »

Yes, they are all made by the same firm I believe. I bank with Nationwide and Natwest and use either card reader for both.

The ones you refer to are part of the Xiring O2S range. Barclays PINSentry is actually slightly different.