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EMV & ChipBeta
Mobile CVM Results Decoder
Decode the Amex ExpressPay Mobile CVM Results (tag 9F71) — the 3-byte object a mobile wallet returns in the GPO response reporting whether on-device CVM was performed, required, and its result.
9F71 Mobile CVM Results — Amex Kernel 4 3 bytes / 6 hex chars
American Express (Kernel 4) only. In Mastercard (Kernel 2) data, tag 9F71 is Protected Data Envelope 2; Kernel 2 signals on-device CVM through the Mobile Support Indicator (9F7E) and POS Cardholder Interaction Information (DF4B) instead. In Discover (Kernel 6) data, 9F71 is the Card Processing Requirements.
The code values come from a single source: the ExpressPay 3.0 table ("Table 12: Mobile CVM Results") as published in binaryfoo emv-bertlv. Byte 3 00 is not in that table; it is shown as "Unknown", as in the EMV CVM Results (9F34).
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