Method for the secure unindirectional transmission of signals
First Claim
1. A method for transmitting a signal via a unidirectional communications link, protected by an asymmetric cryptography method, comprising:
- incrementing, at a transmitter, a counter value, the counter value being incremented based on occurrence of a transmission procedure;
determining, at the transmitter, a challenge based on the counter value and a control command executable by a receiver;
determining, at the transmitter, a response based on the challenge using a private key of the asymmetric cryptography method;
deriving an integrity key at the transmitter based on the response, and generating a cryptographic checksum with the integrity key via the challenge to protect the integrity of the challenge; and
transmitting the challenge, the cryptographic checksum, and the response, from the transmitter to the receiver.
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Accused Products
Abstract
A method transmits a signal using a unidirectional communications link, which is protected by an asymmetric cryptography method. A counter value is incremented by a transmitter during a transmission operation. Subsequently, a challenge is determined by the transmitter on the basis of the counter value and a control command that can be executed by a receiver and, on the basis of the challenge that is determined a response is in turn determined. The challenge and the response are transmitted from the transmitter to the receiver. The challenge received is then checked by the receiver to see whether the counter value used in the challenge is greater than a counter value previously stored by the transmitting transmitter. The response received is checked on the basis of the challenge. Following successful checking of the challenge and response, the control command transmitted in the challenge is executed.
17 Citations
11 Claims
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1. A method for transmitting a signal via a unidirectional communications link, protected by an asymmetric cryptography method, comprising:
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incrementing, at a transmitter, a counter value, the counter value being incremented based on occurrence of a transmission procedure; determining, at the transmitter, a challenge based on the counter value and a control command executable by a receiver; determining, at the transmitter, a response based on the challenge using a private key of the asymmetric cryptography method; deriving an integrity key at the transmitter based on the response, and generating a cryptographic checksum with the integrity key via the challenge to protect the integrity of the challenge; and transmitting the challenge, the cryptographic checksum, and the response, from the transmitter to the receiver. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for checking a signal transmitted, comprising:
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receiving at a receiver from a transmitter, a challenge, a cryptographic checksum based on an integrity key, and a response pertaining to the challenge, the response being generated based on the challenge using a private key of an asymmetric cryptography process, the integrity key being derived by the transmitter based on the response, and the cryptographic checksum being generated using an integrity key via the challenge to protect the integrity of the challenge; checking, by the receiver, the challenge to determine whether a counter value used in the challenge is greater than a counter reference value previously stored by receiver; checking, by the receiver, the response based on the challenge; and after successful checking of the challenge and the response, executing, by the receiver, a control command used in the challenge. - View Dependent Claims (8)
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9. A transmitter device for unidirectional communications using asymmetric cryptography, comprising:
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a counter having a counter value incremented based on occurrence of a transmission procedure; a challenge device to determine a challenge based on the counter value and a control command executable by a receiver; a response device to; determine a response based on the challenge using a private key of an asymmetric cryptography process; and derive an integrity key based on the response, and generate a cryptographic checksum with the integrity key via the challenge to protect the integrity of the challenge; and a transmitter to transmit the challenge, the cryptographic checksum, and the response to the receiver. - View Dependent Claims (10)
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11. A receiver device comprising:
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a receiver to receive, from a transmitter, a challenge, a cryptographic checksum based on an integrity key, and a response pertaining to the challenge, the response being generated based on the challenge using a private key of an asymmetric cryptography process, the integrity key being derived by the transmitter based on the response, and the cryptographic checksum being generated with an integrity key via the challenge to protect the integrity of the challenge; a checking device to; check the challenge to determine whether a counter value used in the challenge is greater than a counter reference value previously stored by receiver; and check, using a public key known to the receiver, whether the response matches the challenge, wherein a positive determination that the response matches the challenges verifies that the response was generated using the private key; and a processor to execute a control command used in the challenge, after successful checking of the challenge and the response.
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Specification