Secured coprocessor comprising means for preventing access to a unit of the coprocessor
First Claim
1. A method for monitoring an execution of a command by a coprocessor, the method comprising:
- producing, at a start of the execution of the command, an error signal having an active value;
during the execution of the command, monitoring operation of the coprocessor so as to detect any abnormal progress in the execution of the command;
at an end of the execution of the command, taking the error signal to an inactive value unless any abnormal progress in the execution of the command has been detected; and
preventing access to at least one unit to be protected of the coprocessor, while the error signal is on the active value.
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Accused Products
Abstract
The present invention relates to a coprocessor comprising a calculation unit for executing a command, and a securization device for monitoring the execution of the command and supplying an error signal having an active value as soon as the execution of the command begins and an inactive value at the end of the execution of the command, if no abnormal progress in the execution of the command has been detected. The coprocessor further comprises means for preventing access to at least one unit of the coprocessor, while the error signal is on the active value. Application is provided particularly but not exclusively to the protection of integrated circuits for smart cards against attacks by fault injection.
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Citations
29 Claims
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1. A method for monitoring an execution of a command by a coprocessor, the method comprising:
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producing, at a start of the execution of the command, an error signal having an active value; during the execution of the command, monitoring operation of the coprocessor so as to detect any abnormal progress in the execution of the command; at an end of the execution of the command, taking the error signal to an inactive value unless any abnormal progress in the execution of the command has been detected; and preventing access to at least one unit to be protected of the coprocessor, while the error signal is on the active value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A coprocessor having a calculation unit for executing a command, the coprocessor comprising:
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a securization device for monitoring an execution of the command and for producing an error signal having an active value at a beginning of the execution of the command, and having an inactive value at an end of the execution of the command unless any abnormal progress in the execution of the command has been detected; and protection means for preventing access to at least one unit to be protected of the coprocessor, while the error signal is on the active value. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An apparatus having a coprocessor, the apparatus comprising:
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a calculation unit to execute a command; a device operatively coupled to the calculation unit to monitor execution of the command and to produce an error signal having an active value at a beginning of the execution of the command, the error signal having an inactive value at an end of the execution of the command unless an abnormal progress in the execution of the command has been detected; and protection circuitry coupled to the device to prevent access to at least one unit to be protected of the coprocessor, if the error signal has the active value. - View Dependent Claims (22, 23, 24)
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25. A system, comprising:
- a processor;
a bus coupled to the processor; and
a coprocessor coupled to the processor through the bus, the coprocessor including;
a calculation unit to execute a command;
a device operatively coupled to the calculation unit to monitor execution of the command and to produce an error signal having an active value at a beginning of the execution of the command, and having an inactive value at the end of the execution of the command unless an abnormal condition associated with the execution of the command has been detected; and
protection circuitry coupled to the device to prevent access to at least one unit to be protected of the coprocessor, if the error signal has the active value. - View Dependent Claims (26, 27, 28, 29)
- a processor;
Specification