Electricity: electrical systems and devices – Safety and protection of systems and devices – Load shunting by fault responsive means
Reexamination Certificate
2001-07-30
2004-02-10
Toatley, Jr., Gregory J. (Department: 2836)
Electricity: electrical systems and devices
Safety and protection of systems and devices
Load shunting by fault responsive means
C235S492000
Reexamination Certificate
active
06690556
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
Smart cards are known which have an integrated circuit and which are provided with an antenna fitted on the smart card. Contactless transmission of data or energy to the integrated circuit of the smart card is possible by means of this antenna. In this case, the antenna is designed as a secondary coil of a transformer, as a result of which, when the smart card is in sufficient proximity to a primary coil in a terminal, a voltage can be generated in the antenna and the integrated circuit can thereby be supplied with energy. In addition, data can be transmitted into or out of the smart card to the external primary coil in the terminal. These smart cards prove to be highly susceptible to third-party analyses or else to manipulations. Moreover, they are highly susceptible to mechanical loading and are expensive.
Electronic circuits are known which contain security-relevant information and are protected against third-party analysis or else against manipulation by special protective circuits. Various methods have been described for achieving such protection. By way of example, integrated circuits to be protected are provided with a metallic casing made, for example, of silver or titanium, thereby making it possible to prevent the integrated circuit from being read by means of X-rays. Furthermore, it has proved successful to configure an interconnect as a protective shield line in the topmost circuit plane of an integrated circuit and to monitor its physical properties, such as the resistance, the capacitance, etc. When an alteration is ascertained, for example, as a result of short-circuiting, grounding or severing in the event of undesirable observation or manipulation, an alarm signal is triggered. On the basis of this alarm signal, the integrated circuit is transferred into a state referred to as the security mode. In this security mode, by way of example, the contents of the memory cells can no longer be read out, since, by way of example, immediately after the transition to the security mode, they are completely erased and, consequently, the information contained therein is irretrievably lost. As a result, it is no longer possible to read out or manipulate the important information of the integrated circuit, for example code keys or PIN numbers or personal data of the user, which is contained in the program and data memories. Protective circuits of this type prove to be very complicated in terms of circuitry and are very expensive, since they necessitate appreciably enlarged chip areas.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide an integrated circuit having an antenna for the contactless transmission of data or energy which overcomes the above-mentioned disadvantageous of the prior art apparatus of this general type.
With the foregoing and other objects in view there is provided, in accordance with the invention, an integrated circuit having at least one antenna for contactless transmission of data or energy. The integrated circuit includes a plurality of circuit planes configured one above another, and a plurality of circuit sections that are to be protected. The plurality of the circuit sections are located in the plurality of the circuit planes. The integrated circuit also includes at least one antenna for contactless transmission of a signal selected from the group consisting of a data signal and an energy signal. The antenna is configured at a location selected from the group consisting of a location that is above the plurality of the circuit sections and a location that is below the plurality of the circuit sections. The integrated circuit also includes a protective circuit that monitors the plurality of the circuit sections with regard to an attack. The protective circuit is connected to the antenna.
The invention exhibits an integrated circuit whose antenna, for the contactless transmission of data or energy, is realized as part of the integrated circuit and, consequently, is formed in the context of the integrated circuit fabrication process. As a result, it is possible to dispense with a multiplicity of electrical contacts between the antenna and the receiver circuit and, moreover, to reduce the length of the transmission paths from the antenna to the receiver circuit and also to the antenna, which appreciably reduces the losses of signal strength on the transmission path. This makes it possible for the antenna or the receiver for the transmitted signal or the transmitter for the signal to be transmitted to be made simpler and smaller in terms of die size, which makes the integrated circuit more cost-effective. In prior art devices, electrical connecting lines running between an external antenna and an integrated circuit can break due to a flexure of the smart card. However, the inventive integrated circuit with the antenna proves to be less susceptible to mechanical loading caused by flexure of the smart card, since mechanical damage to such connecting lines or to the antenna as is the case in the prior art is now precluded. As a result, the integrated circuit with the antenna according to the invention proves to be less susceptible.
In accordance with an added feature of the invention, the antenna that is integrated in the circuit is not only used as a transmitting or receiving antenna, but furthermore, is also used as a protective shield that is configured above and/or below the circuit sections of the integrated circuit which are to be protected. This is achieved by configuring the antenna in a circuit plane configured above and/or below the circuit plane for the circuit to be protected or the circuit sections to be protected. Protective circuit signals are applied to the antenna, as part of the protective circuit. These signals are transmitted via the interconnect/s of the antenna and are subsequently examined. If significant deviations are ascertained in the context of the examination, then an alarm signal is triggered which transfers the integrated circuit to a security mode. These deviations can be caused by the interconnects of the antenna being short-circuited, interrupted, or altered in their physical properties, for example resistance, capacitance or the like, in such a way that this alteration is identified as an intervention, for example, by mechanical removal of individual layers of the integrated circuit, or by drilling through the protective shield, or by making contact with the interconnects of the antenna.
This multiple function of the antenna as transmitting and receiving element for the transmission of data or energy and also as a protective shield of the protective circuit makes it possible, in turn, to further reduce the chip area required for the realization of the protected, integrated circuit with an antenna, since integrative utilization of the antenna is provided. Furthermore, the required supply lines and outgoing lines of the antenna and of the protective circuit and also the precautions thereof for decoupling the lines can be simplified or reduced.
In this case, the protective shield can be realized both by a single antenna and by a plurality of mutually separate antennas. Such a multiple design of the antennas makes it possible not only to transmit differentiated signals but also to detect, in a spatially differentiated manner depending on the position of the individual antennas, an attack on a specific circuit section to be protected, and thereby to implement, in a targeted manner, differentiated measures for protecting the relevant circuit section or else circuit sections going beyond that.
In accordance with an additional feature of the invention, there is provided, one or more selection elements which are assigned to the antenna and define the function of the antenna as part of the protective circuit or as means for transmitting data or energy. This functional assignment can be effected in such a way that either the protection function or the transmission function is present at one point in time, while the other functionality is provided at ano
Smola Michael
Wegertseder Dominik
Demakis James A
Greenberg Laurence A.
Infineon - Technologies AG
Locher Ralph E.
Stemer Werner H.
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