The kernel will treat it the same but will also apply necessary trimming/padding and handle issuing or not additional Issuer Authentication command basing on AIP and CDOL2 and will set TVR and TSI accordingly. Short answer would be - on the terminal side, please treat tag 91 as binary object that shouldn't be modified, but only passed to the level 2 kernel. Any EMV level 2 compliant terminal will behave in this way as it is verified during the certification process that regardless of the individual schemes implementations tag 91 is passed unmodified and transaction result will not be based on any response code that may be part of individual schemes implementation of IAD. Please keep in mind that some tags are 1 byte while others are 2 bytes long. From the terminal point of view neither IAD nor Issuer Script Commands that may be found in the authorization response should be interpreted, only passed unmodified to the card. We will check for EMV tags from the EMV Tags list. Terminal does not parse it (it is a primitive data object). It is unnecessary for terminal to understand the structure, subelements, etc. (Has nothing to do with scripts.) The decision of the issuer is in the top bit of Byte 2 (bit ONApproved Online). Command successfully executed ‘XX’ bytes of data are available and can be requested using GET RESPONSE. Note that the same list with extended searching options is implemented in our freeware BP-Tools product. (It varies because it allows for discretionary data.) It will contain the decision of the issuer plus flags indicating things to do or not do before completion. List of APDU responses for EMV processing with their description. EMV defines Issuer Authentication Data as a binary tag with length from 8 to 16 bytes. Tag 91 (Issuer Authentication Data) can be 8 to 16 bytes of stuff. EMV is a framework that is used by the payment schemes to build their specifications on top of it.

Emv tag 91