Engineering researchers at the University of Arkansas have developed a unique and robust method to prevent cloning of passive radio frequency (RFID) tags. Researchers developed an exploit that allowed them to perform an array of malicious functions against so called mobile keys A device called BEKey which is the size of a quarter and can be installed in 60 seconds on a proximity card reader could potentially be used to break physical access controls in 80 percent of deployments. The technology, based on one or more unique physical attributes of individual tags, will prevent the production of counterfeit tags.
Source: https://threatpost.com/researchers-block-cloning-passive-rfid-112009/73150/