Hi,
I am testing Realtime Clearing. There is a working key which is exchanged with the RTC switch under a zone key. I decrypted the working key with the clear values of the zone key to get the clear working key values. I then use the message (0200 to the RTC switch) and use the BPTOOLS Crypto calc app which I find here : Payments --> DUKTP(ISO97979) --> DUKPT MAC. The 0200 message has the MAC value in field 128. I then take the whole 0200 message (hex) and put it in the Crypto Calc and use the clear value of the working key to determine the MAC. This is what (I think) the RTC switch does. BUT - the calculated MAC does not match to the MAC in the 0200 message.
Is my method correct ?
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi,
I am testing Realtime Clearing. There is a working key which is exchanged with the RTC switch under a zone key. I decrypted the working key with the clear values of the zone key to get the clear working key values. I then use the message (0200 to the RTC switch) and use the BPTOOLS Crypto calc app which I find here : Payments --> DUKTP(ISO97979) --> DUKPT MAC. The 0200 message has the MAC value in field 128. I then take the whole 0200 message (hex) and put it in the Crypto Calc and use the clear value of the working key to determine the MAC. This is what (I think) the RTC switch does. BUT - the calculated MAC does not match to the MAC in the 0200 message.
Is my method correct ?
123456