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Parse CV Rule from CVM List for EMV

I have succesfully retrieved the CVM List from EMV card.

0000 0000 0000 0000 4103 4203 1E03 1F02

From the EMV specification book 3, the first 4 bytes and second 4 bytes are amount and rest is CV rules. Making these the CV Rule 4103 4203 1E03 1F02

The book also shows how to parse the CV rules, as shown below: enter image description here

I am assuming that I need to convert the first two bytes in a CV rule to binary and match with the table above? But why does the table above have empty cells? Also can someone explain in a simple pseudo code algorithm to parse this?

Solution

  • Have you referred section 10.5.5 CVM Processing Logic in the same book ? It has it detailed and even as a flow cart.

    As to the empty bits read as RFU.

    This is how your sample is parsed.

    41 03

41 => 0100 0001
Apply succeeding CV Rule if this CVM is unsuccessful
Plaintext PIN verification performed by ICC

03
If terminal supports the CVM
---------------------------------------------------

Similarly, 
42 03

42
Apply succeeding CV Rule if thisCVM is unsuccessful
Enciphered PIN verified online

03
If terminal supports the CVM
----------------------------------------------------

1E03

1E
Signature (paper)

03
If terminal supports the CVM

----------------------------------------------------

1F 02

1F
No CVM required

02
If not unattended cash and not manual cash and not purchase
with cashback