IsoDep Transceive Times

ODA Support. All known to us Visa and Mastercard cards, either in plastic form, or within Google Wallet, or Apple Pay support Offline Data Authentication (ODA, also known as fDDA, CDA, DDA).

Overall Tap Latency. It takes between 250 – 800 msec to get data from the card during TAP.

IsoDep Transceive Latency. Pure contactless transceive time is between 215 – 740 Msec. The reader device component latency (my Android phone) is around 100-120 msec.

Modern cards are faster. Newly issued plastic cards have better computation power. Their transceive time is within 315 – 325 msec.

Google Pay is even faster. It reduces the transceive time even more: 165 – 250 msec. It seems that new version of Google Pay which is now called Google Wallet is even faster.

Google Wallet or Apple Pay can be slow. The bad news about Google Wallet and Apple Pay is that it is not easy for a non-trained person to position the phone over the reader in such a way that the speed of data exchange between the card and the reader is optimal. Badly tapped smartphone causes higher tap latency.

You can use Android app, NFC EMV Explorer to measure this yourself.

Details. What is Tap?

The tap starts with card detection in the reader field and ends when the reader retrieves all data from the card necessary to finish the transaction without further card participation. NFC EMV Explorer implements the following sequence of transceive APDUs.

  1. Select PPSE 2,
  2. Select ADF (application),
  3. Get Processing Options,
  4. Read all data specified in AFL.
  5. Generate AC (when applicable).

The card can be removed from the reader field after that. The reader does not need more data from the card for Offline Data Authentication and transaction completion.

For Visa, the process ends on step 4. All data necessary for ODA (fDDA) is already provided by the card to the reader.

Mastercard CDA requires Generate AC as described in EMV Kernel 2. This will provide enough data to finish ODA (CDA).

Interac (Canadian proprietary debit scheme and EMV Card application) also requires Generate AC but this card application does not always support ODA. It supports static data authentication which requires Issuer-side verification to check whether the card ais authentic.

NFC EMV Explorer executes Generate AC for Mastercard and Interac and measures the latencies.