Cryptographic key exchange over an electrostatic channel
First Claim
1. An interactive display device comprising:
- a touch sensor including a plurality of electrodes, where the interactive display device is configured to excite one or more electrodes of the touch sensor according to a touch-sensing frame performed repeatedly to sense touch input to the touch sensor, the touch-sensing frame being divided into a plurality of different time slots including at least a touch-sensing time slot and an information-sending time slot, where the one or more electrodes of the touch sensor form a capacitive coupling with an electrode of an input device, where the interactive display device is configured to use the capacitive coupling to determine a position of the input device during the touch-sensing time slot, and where the interactive display device is configured to use the capacitive coupling to capacitively send a cryptographic key via an electrostatic channel to the input device during the information-sending time slot; and
a radio transceiver configured to communicate via a radio channel, where the interactive display device is configured to subsequently exchange encrypted communications over the radio channel, the encrypted communications being encrypted using the cryptographic key.
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Abstract
Various embodiments relating to exchanging a cryptographic key between a display device and an input device via electrostatic communication are disclosed. In one embodiment, an interactive communication device includes one or more electrodes and a radio transceiver. The one or more electrodes may be excited to capacitively couple with one or more electrodes of a proximate communication device so as to capacitively send a cryptographic key from the interactive communication device to the proximate communication device. The radio transceiver may be configured to communicate with a radio transceiver of the proximate communication device via a radio channel. The interactive communication device may be configured to subsequently exchange encrypted communications with the proximate communication device over the radio channel. The encrypted communications may be encrypted using the cryptographic key.
40 Citations
20 Claims
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1. An interactive display device comprising:
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a touch sensor including a plurality of electrodes, where the interactive display device is configured to excite one or more electrodes of the touch sensor according to a touch-sensing frame performed repeatedly to sense touch input to the touch sensor, the touch-sensing frame being divided into a plurality of different time slots including at least a touch-sensing time slot and an information-sending time slot, where the one or more electrodes of the touch sensor form a capacitive coupling with an electrode of an input device, where the interactive display device is configured to use the capacitive coupling to determine a position of the input device during the touch-sensing time slot, and where the interactive display device is configured to use the capacitive coupling to capacitively send a cryptographic key via an electrostatic channel to the input device during the information-sending time slot; and a radio transceiver configured to communicate via a radio channel, where the interactive display device is configured to subsequently exchange encrypted communications over the radio channel, the encrypted communications being encrypted using the cryptographic key. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An input device configured to interact with an interactive display device, the input device comprising:
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an electrode configured to be excited to form a capacitive coupling with one or more electrodes of a touch sensor of the interactive display device, where the interactive display device is configured to excite electrodes of the touch sensor according to a touch-sensing frame performed repeatedly to sense touch input to the touch sensor, the touch-sensing frame being divided into a plurality of different time slots including at least a touch-sensing time slot and an information-sending time slot, where the interactive display device is configured to use the capacitive coupling between the electrode of the input device and the one or more electrodes of the touch sensor to determine a position of the electrode of the input device during the touch-sensing time slot, and where the input device is configured to use the capacitive coupling between the electrode of the input device and the one or more electrodes of the touch sensor to capacitively send a cryptographic key via an electrostatic channel to the interactive display device during the information-sending time slot; and a radio transceiver configured to communicate via a radio channel, where the input device is configured to subsequently exchange encrypted communications over the radio channel, the encrypted communications being encrypted using the cryptographic key. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method for transmitting information between an interactive display device and an input device, the method comprising:
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repeatedly performing a touch-sensing frame to detect touch input to a touch sensor of the interactive display device, the touch-sensing frame divided into a plurality of different time slots including at least a touch-sensing time slot, and an information-sending time slot; during the touch-sensing time slot, sensing excitation of an electrode of the input device to receive position information from the input device via a capacitive coupling between the electrode of the input device and one or more electrodes of the touch sensor; during the information-sending time slot, sending a cryptographic key from the interactive display device to the input device via the capacitive coupling between the electrode of the input device and the one or more electrodes of the touch sensor; and subsequently exchanging encrypted communications with the input device over a radio channel formed between a first radio transceiver of the interactive display device and a second radio transceiver of the input device, the encrypted communications being encrypted using the cryptographic key. - View Dependent Claims (18, 19, 20)
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Specification