Magnetic stripe reader tamper protection
AssigneeSquare, Inc.
InventorsJeremy Wade, Max Joseph Guise
Life of this patent
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Abstract
A technique for tamper protection of incoming data signal to an electronic device is disclosed. An intentional interference signal is generated and modulated onto the incoming data signal as one composite input signal, to prevent unauthorized acquisition of valid data from the incoming data signal. The magnitude of the interference signal is adjusted to correspond to the magnitude of the incoming data signal, thereby preventing an attacker from properly differentiating the two different signals and/or decoding the valid data from the composite input signal. Once the composite input signal is safely received within the device, the interference signal can be filtered out in either analog mode or digital mode.
Claims23
An electronic device comprising:
- a card interface having one or more card interface terminals and configured to read data from a payment card during a read of the payment card at the electronic device and to generate a data signal that represents the data read from the payment card;
- a signal generator configured to generate an interference signal and to introduce the interference signal to the data signal within the card interface as an electrical current received via one of the one or more card interface terminals;
- and
- a filter configured to:
- receive, as an electrical current at a first input terminal via one of one or more card interface terminals, a composite signal including the interference signal and the data signal that represents the data read from the payment card,
- generate an output signal that represents the data read from the payment card by filtering the interference signal from the composite signal, and
- output, at an output terminal, the output signal.
A method comprising:
- generating a data signal at a card interface of a first device;
- generating an interference signal by a signal generator;
- providing the interference signal as an electrical current to one of one or more card interface terminals of the card interface;
- combining the interference signal with the data signal within the card interface to form a composite signal;
- receiving the composite signal as an electrical current at an input terminal via one of the one or more card interface terminals;
- filtering the interference signal from the composite signal between the input terminal and the output terminal of the first device to form a filtered data signal;
- and
- transmitting the filtered data signal via the output terminal to a second device coupled to the first device.
A payment card reader comprising:
- a card interface having one or more card interface terminals and configured to read a first data signal from a payment card during a read of the payment card at the payment card reader;
- a first signal generator configured to generate a first interference signal and to provide the first interference signal as an electrical current to one of the one or more card interface terminals;
- and
- a first amplifier having a first input terminal, a second input terminal, and a first output terminal, wherein the first amplifier is configured to:
- receive, at the first input terminal, a first composite signal as an electrical current via one of the one or more card interface terminals, the first composite signal comprising the first interference signal and the first data signal,
- generate a first output signal by filtering the first interference signal from the first composite signal, and
- output, at the first output terminal, the first output signal.
Dependencies are inferred from the claim text.