Update October 12th, 2015

Dear System Integrator,

this letter serves to further inform you on the situation concerning the security deficiencies of our MIFARE Classic® product. We already sent out information letters on this subject in 2008 and 2015.

NXP Semiconductors is aware of the fact that several research groups have developed attacks to break keys of MIFARE Classic®-enabled cards. Amongst others there are the group around Karsten Nohl and Henryk Ploetz, who initially presented the reverse engineering of MIFARE Classic® chips in December 2007 at the 24th Chaos Computer Congress in Berlin, the IT security specialists from the Radboud University of Nijmegen as well as Nicolas T. Courtois from the University College London. The latest attack was performed by the digital security of Radboud University Nijmegen, which was published in October 2015.

We have investigated protection scenarios for systems using MIFARE Classic®, as in some systems insufficient mechanisms to detect fraudulent cards may have been implemented and on the efficiency of fully diversified keys. As before, we will be happy to share our information with you, especially in light of your specific expertise in designing systems. Mindful of the aforementioned, we urgently ask to closely assess your systems. Extensive additional protection mechanisms are recommended, both on how the data on the card is used as well as deploying additional security layers separate from the card. Naturally, your risk assessment depends on the assets to be protected and whether the end-to-end system still meets the end customer’s requirements.

End to end measures should also be applied for access management infrastructures, often by complementing systems with additional measures e.g. camera surveillance, security personnel, etc. when valuable assets need to be protected. We recommend that your assessment of the impact of the recent and expected developments takes into account the particular way how the system is implemented and used, its relation to other protection in place, and specifically whether there is a need to prevent unauthorized single time access or access during a limited period of time. Depending on the specific situation in existing MIFARE Classic® access management infrastructures, in many cases the usage of more sophisticated card ICs may be recommendable. MIFARE Plus® and MIFARE® DESFire® are our recommended solution for new access management implementations where a strong level of security is required.

MIFARE Classic® provides a benchmark in cost competitiveness, while the recently announced MIFARE Plus® SE enables an optimal future-proof migration path, specifically for 1K installations, when necessary. Both MIFARE Plus® and our high-end product MIFARE® DESFire® offer strong AES encryption and are certified according to Common Criteria certification.

NXP’s expertise is the design and manufacturing of chips; although we do not design end to end security systems, we would be happy to continuously support you so that the best solutions in the interest of your customers are reached.

If you would have any questions, please contact us at mifare@nxp.com. If, in addition, you would like to be kept informed about the developments in this matter, please send an email to mifare@nxp.com as well.

Sincerely yours