How to troubleshoot a CDA failure

Problem

Which CAPK is needed?

Check the card brand

Use the LIST OF CA PUBLIC KEYS as a reference. Identify the card brand (Visa, Mastercard, American Express, Discover, etc.) and set the filter accordingly.

Confirm test or live CAPK

Determine whether the card is a test card or a live card. Test cards usually identify themselves as test cards in printed text on the card. Live cards typically do not. Search the CAPK list for "Test" or "Live" and choose the first matching CAPK that is not expired.

Open

Example filter

The filtered list should show CAPKs for the selected brand and card type. Use the screenshot below as a visual reference.

Pull the CAPK index from a contact-capable device

If you have a contact-capable reader, use uDemo to run a contact EMV transaction and retrieve the CAPK index directly from the card data.

1. Connect the reader to uDemo and confirm the correct device is recognized.

2. Make sure the reader has the required terminal data and AIDs loaded so it can start a contact EMV transaction.

3. Insert the card and run a contact EMV transaction.

4. After the transaction finishes, promptly use EMV > Retrieve Tags to retrieve the transaction tags. Transaction data is typically available only briefly after the transaction.

5. Look for tag 8F or 9F22. This one-byte value is the CAPK index requested by the card.

6. Combine the card brand RID with the CAPK index to identify the required CAPK. For example, if the RID is A000000025 and tag 8F is 2F, the required CAPK is A0000000252F.

Load the CAPK

After you identify the required CAPK, load it to the reader using one of the procedures below:

• How to Load an EMV CAPK from a File Using uDemo

• How do I set CAPKs for L3 certification?

Use the attached CAPK file as needed: