EMV Tag 91 - why the last 2 bytes are "0010"?

Question

EMV Tag 91
in the following example, why the last 2 bytes are "0010"? example: TLV [910ABCF266A64FF136630010] I need most help Thanks!!!

Answer 1

The first 8 bytes are mandatory and contain the cryptogram.

The optional 1–8 bytes that follow are proprietary. Therefore, you need to know what payment application (and version) you are using: e.g., Mastercard M/Chip, American Express AEIPS, etc.

See 6.5.4 External Authenticate in EMV 4.3 Book 3

Answer 2

This Tag 0x91 Issuer Authentication Data belongs to MasterCard M/Chip specification.

• 8 bytes is Authorization Response Cryptogram (ARPC).
• 2 Bytes is ARPC Response Code (RC) according to M/Chip specification.

The RC value set by M/Chip card issuer and provide additional card commands to reset some counters on it.

The example Tag data parsed as followed:

# Cheef's parser.
# Copyright (C) 2008-2022 Aleksandr Shevelev. https://iso8583.info/
# lib   : "/lib/MasterCard/M_Chip/4/" # M/Chip 4 Card Application Specifications
# tool  : "TLVs"

# stat  : 11 nodes, 0 lookup tables, 100.00% passed (1/1)

TLVs:#"910ABCF266A64FF136630010" # M/Chip 4, Tag + Length + Value (TLV) series
- x91:#"910ABCF266A64FF136630010" # M/Chip 4, Issuer Authentication Data
  - tag: "91"
  - len: "0A" #  // 10
  - val:#"BCF266A64FF136630010" # Issuer Authentication Data.
    - ARPC: "BCF266A64FF13663" # Authorization Response Cryptogram
    - RC:#"0010" # ARPC Response Code
      - B01:#"00"
        - n0: "0" # bits 8-5, RFU
        - n1: "0" # bits 4-1, PIN try Counter
      - B02: "10"
        # ___1____ - bit 5, Approve online transaction
        # ____0___ - bit 4, Do NOT update PIN Try Counter
        # _____0__ - bit 3, Reset go online on next transaction
        # ______00 - bits 2-1, Do not update offline counters