EMV card + NFC reader send PDOL and get data SFI

Question

I try to get payment data from my emv-card and use for it arduino + nfc modules. It's work fine, but I have some difficult to get SFI. I test it on VISA card. I get request from card (answer) like:

6F 42 84 07 A0 00 00 00 03 10 10 A5 37 50 0D 56 49 53 41 20 49 4E 46 49 4E 49 54 45 87 01 01 9F 38 0C 9F 66 04 9F 02 06 9F 37 04 5F 2A 02 5F 2D 08 75 6B 72 75 65 6E 64

so, it's wait from me:

9F66 04
9F02 06
9F37 04
5F2A 02 

and I send:

9F66 (TTQ) - 0xF8, 0x00, 0x40, 0x00
9F02 (Amount) - 0x00, 0x00, 0x00, 0x00, 0x14, 0x00,
9F37 (Rand num) - 0x36, 0xD3, 0xEC, 0x39,    
5F2A (currency code) - 0x09, 0x80

and I get answer (data from track2 was changed):

77 66 82 02 00 00 94 04 08 02 02 00 57 13 44 41 11 11 11 11 11 97 D2 99 02 01 17 32 43 14 00 00 0F 5F 34 01 00 9F 10 07 06 01 11 03 80 20 00 9F 26 08 C9 D9 34 2A 7D 58

From this data I get Application File Locator (AFL) and it:

08 02 02 00

I decode it to send apdu like:

0x00, 0xb2, 0x02, 0x0c, 0x00

and get answer:

70 0A 9F 07 02 C0 80 5F 28 02 08 04 90 00

And it's very minimalistic, and don't have any useful data/info (it's need create field 55). I was search AFL must have more then one record and it's need to make it loop, but I get only one. Maybe the TTQ is wrong? Please help! Thanks!

Answer 1

This case is for Contactless MSD of EMVCo C-3 Visa PayWave kernel. According EMVCo C-3 PayWave AFL Tag 0x94 is optional in GPO reply.

In GPO replay you already receive all necessary data including AIP, AFL, CSN, Track 2, IAD and Cryptogram values. IAD Tag 0x9F10 showing AAC cryptogram returned after 1st Generate AC, i.e. rejection. This data is enough to continue and finish transaction.

You may play with 0x9F66 TTQ value to exclude MSD support. Contactless MSD support removed from the live terminals. Forcing Contactless EMV you may get other AFL values or again you will get all Tags directly in GPO reply.

The TLV parsing tool for PayWave C-3 you may find here - https://iso8583.info/lib/EMV/C3/TLVs