Communication data protection method based on symmetric key encryption in RFID system, and apparatus for enabling the method

A communication data protection method using an RFID tag, the method comprising:

• transmitting, to a reader, tag information including security parameter information, protocol control bits, a cyclic redundancy check and an unique item identifier, the protocol control bits, cyclic redundancy check and the unique item identifier encrypted by a One Time Pad using a One Time Pad value generated by a symmetric key-based encryption algorithm;
• receiving, from the reader, a request message including a challenge value for replay prevention;
• and
• generating a handle in response to the request message and transmitting, to the reader, a response message including the handle and the challenge value,
• wherein the One Time Pad value is successively selected not to be overlapped among a plurality of One Time Pad values generated according to an Output Feedback (OFB) operation mode of the symmetric key-based encryption algorithm, and all messages transceived between the reader and the tag after the tag information is received at the reader are encrypted and transmitted.

An RFID tag comprising:

• a memory to store a security parameter and a security key value;
• a signal processing unit to generate a One Time Pad value based on an Output Feedback operation mode using the security key value in a symmetric key-based encryption algorithm and to encrypt a transmission message to be transmitted to a reader using the One Time Pad value;
• and
• a transmission unit to transmit messages to the reader,
• wherein the signal processing unit generates a plurality of One Time Pad values based on the Output Feedback operation mode of the symmetric key-based encryption algorithm, sequentially selects the plurality of One Time Pad values so as to not be duplicated, and encrypts all transmission messages transceived between the reader and the tag after a security response message containing the security parameter is received from the tag at the reader using the sequentially selected plurality of One Time Pad values.

A communication data protection method, the method comprising:

• transmitting a security command message including a random value request from a reader to a tag;
• receiving the security command message including the random value request at the tag;
• generating the random value at the tag;
• transmitting, using the tag, the random value to the reader;
• encrypting a security parameter setting information at the reader by performing an exclusive “OR” calculation of the security parameter using the random value;
• receiving, from the reader, a setting command message including the encrypted security parameter setting information;
• authenticating the reader at the tag using the random value;
• setting a security parameter value of a security memory back at the tag based on the security parameter setting information;
• and
• generating a response message including the random value and header information and transmitting the response message to the tag,
• wherein all messages transceived between the reader and the tag are encrypted using an One Time Pad value successively selected not to be overlapped among a plurality of One Time Pad values generated according to an Output Feedback (OFB) operation mode of a symmetric key-based encryption algorithm.

A communication data protection method, the method comprising:

• transmitting a security command message including a random number value request from a reader to a tag;
• receiving the security command message including the random value request at the tag;
• generating the random value at the tag;
• transmitting, using the tag, the random value to the reader;
• encrypting a most significant 16-bit value of a security key by performing an exclusive “OR” calculation of the security key using the random value;
• receiving, from the reader, security key update key command;
• decrypting the security key update command using the random value;
• and
• setting a stored security key in tag memory based on the security key received from the reader, and transmitting a response message to the reader,
• wherein all messages transceived between the reader and the tag are encrypted using an One Time Pad value successively selected not to be overlapped among a plurality of One Time Pad values generated according to an Output Feedback (OFB) operation mode of a symmetric key-based encryption algorithm.