A:
Tag 57 is the Track 2 Equivalent Data in the EMV transaction payload. You can refer to the format definition of tag 57 from Visa CTLS spec. to make out the rest of the values in the 57 tag.
Below is the breakdown of the sample tag 57 value: 12 34 56 78 90 00 98 76 d2 41 02 01 00 00 03 20 00 00 1f.
12 34 56 78 90 00 98 76 is the PAN
d is the field separator
2410 is the expiration date (YYMM)
201 is the service code
00 00 03 20 00 00 1 is the PIN verification data (if present) and the discretionary data
f is the padding to ensure the whole bytes
Different card brands have their own tags for the same data.
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