Whereas Lynn's hack of IOS was considered novel, however, the IOActive demonstration of RFID vulnerabilities is largely a rehash of known issues, intended more as an introduction, Moss said.

"They've known about this for years and years," Moss said.

Kathleen Carroll, a spokeswoman for HID's Government Relations group acknowledged that a letter was sent to IOActive but that it did not mention patent infringement. She said that the company has long been aware that its proximity cards are vulnerable to hacking but does not believe that the cards are as vulnerable as Paget suggests.

"For someone to be able to surreptitiously read a card, they'd have to get within two or three inches and get into the same plane as the card," Carroll said.

HID is also concerned that Paget's demonstration will popularize the vulnerabilities in its proximity cards and endanger its many customers.