IAD Decoder
Decode Issuer Application Data (EMV tag 9F10) for Visa (IAD formats 0–4), Mastercard M/Chip 4 / M/Chip Advance and EMV CCD-compliant cards: DKI, CVN, counters and a bit-level Card Verification Results breakdown.
Follows Visa VIS / VCPS · Mastercard M/Chip 4 / Advance · EMV Book 3 CCDVisa IAD formats 0–4, M/Chip CVN 10 / 11 / 14 / 15, CCD Format A·verified Oct 2026· double-checked Oct 2026— CVR layouts cross-checked against jPOS, openemv/emv-utils and pyemv over 5,120 single-byte cases; single-source bits are flagged in the page
What the Issuer Application Data (9F10) carries
The Issuer Application Data (IAD), EMV tag 9F10, is a variable-length container (up to 32 bytes) the card returns with its application cryptogram. The terminal passes it unchanged to the issuer in the authorisation request. It carries what the issuer needs to verify the cryptogram, plus a report of what the card's own risk management decided.
Why the format depends on the scheme
EMV leaves the IAD layout to the payment system, so the same tag is laid out differently for Visa and Mastercard. CCD-compliant applications use the common layout in EMV Book 3 Annex C. Visa uses IAD formats 0, 1 and 3 (06 | DKI | CVN | CVR, with a 4-byte CVR that starts with its length 03) and the 32-byte formats 2 and 4 (1F | CVN | DKI | 5-byte CVR | issuer data). The CVN's high nibble is the format number. Mastercard M/Chip uses DKI | CVN | 6-byte CVR | DAC/ICC dynamic number | counters. The tool auto-detects the layout from these signatures. Auto-detect can misread a Visa format 0/1 value whose DKI is 10, 11, 14 or 15 and whose length is 18, 20, 26 or 28 bytes: it also fits the M/Chip signature and is read as M/Chip. Select Visa in the scheme selector to override. The Cryptogram Version Number (CVN) tells the issuer how the ARQC was computed: the key derivation, the session key and the data included. A mismatch here is a leading cause of cryptogram-validation failures at the host.
Common questions
Why does my IAD not parse?
Check that you pasted only the value of 9F10, without the tag and length bytes. Amex, JCB, Discover and UnionPay IADs use their own layouts and are not decoded here. If you know the scheme, select it to force that layout.
What is the CVR used for?
The Card Verification Results report the card's own risk-management results: which cryptogram it returned, the offline PIN outcome, exceeded offline counters and the status of the last online transaction. The issuer sees what the chip did, not just what the terminal reported.
Layouts follow the Visa VCPS / VIS IAD formats, Mastercard M/Chip requirements and EMV Book 3 Annex C, cross-checked against the open-source emv-utils and pyemv libraries. All parsing happens locally in your browser — nothing you paste is transmitted or stored.