Forum › MIFARE SmartCard IC`s › MIFARE DESFire › Mifare DESFire EV1 problem › Reply To: Mifare DESFire EV1 problem
After speaking with both HID and NXP the cause seems to be heat related. Below is a response from NXP:
“Further to our recent discussions regarding the troubles one of your customers is facing with Desfire-based cards, I have asked our technical support team to investigate the case.
We understand that your customer experienced cards failing to function at the end of the printing process for a period of 20 to 30 minutes, restarting to operate as normal after that.
You also explained us that your customer recently upgraded their printing equipment and process (printing on both sides).
Based on our experience and your inputs, we believe that the printing process used by your customer triggers a security feature of the Desfire IC linked to an overheating of the card body. Outside a specific range, the chip interprets high temperature as a security attack, and turns “silent”. The upper limit is set at 70°C.
As such, we advise your customer to fine tune their printing process to confirm this interpretation and ultimately to define a sustainable process.”
“Further to our recent discussions regarding the troubles one of your customers is facing with Desfire-based cards, I have asked our technical support team to investigate the case.
We understand that your customer experienced cards failing to function at the end of the printing process for a period of 20 to 30 minutes, restarting to operate as normal after that.
You also explained us that your customer recently upgraded their printing equipment and process (printing on both sides).
Based on our experience and your inputs, we believe that the printing process used by your customer triggers a security feature of the Desfire IC linked to an overheating of the card body. Outside a specific range, the chip interprets high temperature as a security attack, and turns “silent”. The upper limit is set at 70°C.
As such, we advise your customer to fine tune their printing process to confirm this interpretation and ultimately to define a sustainable process.”
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