NXP Statements
17 March 2008NXP has released two statments about Mifare security: Information for end users and Information for system integrators.
The statements appear to be nearly identical. The excerpt below is from the statement for end users:
In December 2007 a group of researchers at the 24th Chaos Computer Club in Berlin claimed that they reverse engineered a MIFARE Classic chip and partially discovered the encryption algorithm of the chip. At the same time, they stated that they were not yet able to recover any keys from the chip.
NXP has come to the conclusion that two research groups have by now retrieved the algorithm and developed attacks which can be done with faster means of breaking keys than brute force. Although we are trying to prevent this, there is a risk of the full algorithm becoming publicly known and we feel it is appropriate to inform you about the potential consequences and necessary measures to be taken to minimize the impact of such eventuality for your system infrastructure.
Although we trust that you have worked with a system integrator who has implemented in your systems effective mechanisms to detect fraudulent cards (which we understand is possible in a number of ways), we want to inform you that we are investigating scenarios how MIFARE Classic systems can be protected Mindful of the above, we ask you to contact your system integrator to assess whether your systems would need any additional security measures.
It is our assessment that for transport ticketing installations, end-to-end security systems can be designed with the MIFARE Classic chip such that the residual risk of fraud not being detected in time can be drastically reduced. Whether or not those scenarios are acceptable in your risk assessment depends on the assets to be protected which only you and your system integrator can determine.
End to end measures should also be applied for access management infrastructures, which are often complemented by 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 that 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.
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