Improvement of the RFID authentication scheme based on quadratic residues

RFID, with its capability of remote automatic identification, is taking the place of barcodes and becoming the new generation of electronic tags. However, information transmitted through the air is vulnerable to eavesdropping, interception, or modification due to its radio transmission nature; the prevalence of RFID has greatly increased security and privacy concerns. In 2008, Chen et al. proposed an RFID authentication scheme which can enhance security and privacy by using hash functions and quadratic residues. However, their scheme was found to be vulnerable to impersonation attacks. This study further demonstrates that their scheme does not provide location privacy and suffers from replay attacks. An improved scheme is also proposed which can prevent possible attacks and be applied in environments requiring a high level of security.