Encryption for modulated backscatter systems
First Claim
Patent Images
1. A method of radio communication, comprising:
- transmitting a radio signal from an interrogator to a tag;
in the tag, modulating a reflection of the radio signal using, at least in part, a unique identifier, thereby forming a reflected radio signal modulated by the unique identifier;
in the interrogator, receiving and demodulating the reflected radio signal modulated by the unique identifier, thereby recovering the unique identifier;
in the interrogator, generating a random challenge, and transmitting the random challenge and the unique identifier to an application processor; and
in the interrogator, modulating the radio signal using the random challenge, thereby forming a radio signal modulated by the random challenge, and transmitting to the tag the radio signal modulated by the random challenge.
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Abstract
A tag and an interrogator exchange proprietary information using Modulated BackScatter (MBS) technology. A method for encrypting the RFID user'"'"'s PIN and thereby making the interception and the subsequent illegal use of RFID accounts at least as difficult as a present day ATM cards. For example, the encryption method can be based upon the US Digital Encryption Standard (DES), either first or third level. The Tag'"'"'s personal encryption key is only known by the financial database and the RFID Tag. This method can be applied to any type of financial, debt, identification, or credit card.
539 Citations
9 Claims
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1. A method of radio communication, comprising:
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transmitting a radio signal from an interrogator to a tag; in the tag, modulating a reflection of the radio signal using, at least in part, a unique identifier, thereby forming a reflected radio signal modulated by the unique identifier; in the interrogator, receiving and demodulating the reflected radio signal modulated by the unique identifier, thereby recovering the unique identifier; in the interrogator, generating a random challenge, and transmitting the random challenge and the unique identifier to an application processor; and in the interrogator, modulating the radio signal using the random challenge, thereby forming a radio signal modulated by the random challenge, and transmitting to the tag the radio signal modulated by the random challenge. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification