Integrated circuit with tamper detection circuit
First Claim
1. An integrated circuit having a tamper detection circuit including:
- a noise generator circuit;
a first line connected to the noise generator circuit; and
a second line connected to the noise generator circuit by an inverter;
wherein operation of one or more general circuits of the integrated circuit is dependent upon a logical combination of signals on the first line and the second line.
3 Assignments
0 Petitions
Accused Products
Abstract
A tamper detection circuit for an integrated circuit includes a pseudo-random generator. A first line is connected to the output of the generator and a second line is connected in parallel via an inverter. A number of XOR gates are coupled to the first and second lines at locations along their length. Output from the XOR gates enables various general operational circuits of the integrated circuit. In the event of one of the lines being cut or otherwise tampered with then the output from the XOR gates will indicate a tamper state. The general operational circuits respond by either resetting or deleting critical data from memory such as the integrated circuit'"'"'s authentication key. In a preferred version a number of trigger transistors connected to ground are inserted into the paths of the first line and the second line. A physical attack upon the integrated circuit causes a nearby trigger transistor to pull its attached line to ground thereby causing the output of local XOR gates to indicate a tamper state.
71 Citations
13 Claims
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1. An integrated circuit having a tamper detection circuit including:
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a noise generator circuit;
a first line connected to the noise generator circuit; and
a second line connected to the noise generator circuit by an inverter;
wherein operation of one or more general circuits of the integrated circuit is dependent upon a logical combination of signals on the first line and the second line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An integrated circuit of a type including a number of general operational circuits and a tamper detection circuit to which said general operational circuits are responsive, the tamper detection circuit including:
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a pseudo random bit generator clocked at high speed relative to other circuitry of the integrated circuit;
a first line connected to the random bit source and disposed in a layer vertically displaced relative to a layer containing the general operational circuits; and
a second line connected to the random bit source and disposed in a layer vertically displaced relative to the layer containing the general operational circuits;
a number of XOR gates coupled at locations along the first line and the second line;
a plurality of triggers attached to the first line and to the second line each of the triggers being configured to alter the voltage on the first line or the second line to which it is attached in response to a physical attack on the integrated circuit.
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Specification