Method of measuring distance bound using radio frequency identification (RFID) and system thereof
First Claim
1. A method in which a tag assists in measuring a distance bound, the method comprising:
- receiving a plurality of queries from a reader;
deciding a response value based on a random number ci included in each query of the plurality of queries and a first bit created in advance through protocol initialization with the reader;
determining whether or not to transmit a response including the response value based on a random number mi included in each query of the plurality of queries and a second bit created in advance through the protocol initialization with the reader;
transmitting the response to the reader if it is determined that the response has to be transmitted; and
calculating a message authentication code based on the random number ci, the random number mi, and the response value, and transmitting the message authentication code to the reader.
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Accused Products
Abstract
A tag decides a response based on a plurality of queries received from a reader, determines whether to transmit the response, transmits the response to the reader according to the results of the determination, and transmits a message authentication code including communication content to the reader. The reader calculates a consumed time period which is the time difference between a transmission time at which the queries are transmitted and a reception time at which the response is received, calculates an average consumed time period of the consumed time period, and measures a distance to the tag based on the average consumed time period. Accordingly, it is possible to check an attacker'"'"'s intervention with a high probability, thereby improving distance measurement performance. Also, the tag may efficiently perform computing and communication.
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Citations
16 Claims
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1. A method in which a tag assists in measuring a distance bound, the method comprising:
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receiving a plurality of queries from a reader; deciding a response value based on a random number ci included in each query of the plurality of queries and a first bit created in advance through protocol initialization with the reader; determining whether or not to transmit a response including the response value based on a random number mi included in each query of the plurality of queries and a second bit created in advance through the protocol initialization with the reader; transmitting the response to the reader if it is determined that the response has to be transmitted; and calculating a message authentication code based on the random number ci, the random number mi, and the response value, and transmitting the message authentication code to the reader. - View Dependent Claims (2, 3, 4, 12)
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5. A method in which a reader measures a distance bound, the method comprising:
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selecting a plurality of queries and transmitting the plurality of queries to a tag, the plurality of queries comprising each query including a random number ci and a random number mi; measuring a transmission time at which the plurality of queries are transmitted; in response to the plurality of queries, receiving, depending on the random number mi, at least one response ri which is based on the random number ci; measuring a reception time at which the response is received, and calculating a consumed time period which is a time difference between the transmission time and the reception time; receiving from the tag a message authentication code which is based on the random number ci, the random number mi, and the response ri, and verifying the message authentication code; and calculating an average consumed time period of the consumed time period if it is determined that the message authentication code is correct based on the results of the verification. - View Dependent Claims (6, 13, 14, 15, 16)
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7. A tag comprising:
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a tag processor configured to decide a response value based on a random number ci included in each query of a plurality of queries received from a reader and a first bit created in advance through protocol initialization, to determine whether or not to transmit a response including the response value to the reader based on a random number mi included in each query of the plurality of queries and a second bit created in advance through the protocol initialization, to transmit the response according to the results of the determination, to calculate a message authentication code based on the random number ci, the random number mi, and the response value, and to transmit the message authentication code to the reader; and a tag transceiver configured to communicate with the reader. - View Dependent Claims (8, 9, 10, 11)
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Specification