And that, according to Ken van Wyk, principal consultant at KRvW Associates, is a big security problem.
"It turns out it's a pretty huge deal," said van Wyk in a previous interview. "There are a lot of these things floating around out there. Using it for building locks is the biggy, especially when it's used in sensitive government facilities -- and I know for a fact it's being used in sensitive government facilities."
Van Wyk noted in March that one European country had deployed soldiers to guard some government facilities that used the MiFare Classic chip in their smart door key cards. "Deploying guards to facilities like that is not done lightly," he said. "They recognize that they have a huge exposure. Deploying guards is expensive. They're not doing it because it's fun. They're safeguarding their systems." Van Wyk declined to identify the European country under discussion.
Manuel Albers, a spokesman for NXP Semiconductors, said previously that the company had confirmed some of Nohl's findings. However, he said there are no plans to take the popular chip off the market.
"The MiFare chip was first introduced in 1994. At the time, the security level was very high," he said in an interview. "The 48-bit key length for encryption was state of the art." In an earlier interview Albers noted that NXP recently released MiFare Plus, which is backward-compatible with the MiFare Classic while offering better security. He said the company did not release the updated chip because of Nohl's findings, but it did use some of his information when designing it.
In a statement on its Web site, the university notes that Mifare smart cards are widely used to control access to buildings and facilities. "All this means that the flaw has a broad impact," according to the release. "Because some cards can be cloned, it is in principle possible to access buildings and facilities with a stolen identity. This has been demonstrated on an actual system. In many situations where these cards are used there will be additional security measures; it is advisable to strengthen these where possible."
The university added that this past March, its researchers informed its government, the Dutch Signals Security Bureau of the General Intelligence and Security Service, and NXP Semiconductor about their findings.
In an interview on Thursday, van Wyk said publishing security research is a common pursuit, but it's a bit harder to deal with for a hardware company.
"You have an RFID chip deployed by the millions," said van Wyk. "Switching that around is extremely costly and won't happen very quickly. It could be it will take them months or a year to do that."
Van Wyk added that it's a "scary" situation for the companies and organizations using these smart cards. "If they're using that for access control to buildings, they'd have to make major changes to their whole access system," he said.