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Patent Issued for Method, Portable Data Carrier, and System for Releasing a Transaction Using an Acceleration Sensor to Sense Mechanical Oscillations

August 27, 2014

By a News Reporter-Staff News Editor at Electronics Newsweekly -- A patent by the inventors Rankl, Wolfgang (Munich, DE); Baldischweiler, Michael (Munich, DE), filed on June 30, 2010, was published online on August 12, 2014, according to news reporting originating from Alexandria, Virginia, by VerticalNews correspondents.

Patent number 8803658 is assigned to Giesecke & Devrient GmbH (Munich, DE).

The following quote was obtained by the news editors from the background information supplied by the inventors: "The invention relates to a method, a portable data carrier and a system for releasing a transaction or for preventing relay attacks using acceleration sensors and a structure on the data carrier.

"With portable data carriers, in particular contactless chip cards it is possible to carry out a so-called relay attack, also referred to as ghost-and-leech attack or wormhole attack. In its simplest form, this attack consists in expanding the communication area of a contactless chip card to a multiple of the original distance. In FIG. 1 there is outlined, for clarification, a possible setup with which a relay attack can be carried out. As a portable data carrier 1 there is shown a contactless chip card of a card holder. With this chip card, without said card holder's knowledge or consent, a communication is set up and a transaction is carried out at an end device 23 several meters away. This kind of transaction is basically not restricted. For example, such a transaction can be a payment transaction at a payment terminal 23.

"This attack works because in today's contactless cards 1 there is no acknowledgement button and the card 1 only has to be presented to the end device 23 for payment. The attacker takes advantage of this property by sojourning, having a special terminal 26 also referred to as a leech terminal, close to the 'authentic' contactless chip card 1 and amplifying the near-field communication 21 such that it still works over a distance of several meters. The attacker having a special data carrier 24, also referred to as a ghost, can thus pay, in a way, with the 'authentic' chip card 1 from some distance. This attack can be expanded by the near-field communication 21 not only being amplified over some few meters, but being completely led via a separate network 27. The attack could happen in practice for example as follows: The first attacker sets up in an indoor swimming center or gym a communication 21 with a contactlessly working chip card in one of the lockers. If he can discover a contactless chip card 1, he connects it via an end device 26, for example a mobile phone, by means of a network 27 to a gateway 25 of a second attacker, who, almost any distance away, goes shopping with the ghost data carrier 24. The near-field communication 21 between the payment terminal 23 and the 'authentic' chip card 1 is extended here via the mobile phone 26 and runs like an 'authentic' transaction.

"Cryptographic means cannot build a protection against this kind of attack. For solving this problem, for example a push-button could be mounted on the contactless card 1, which upon each transaction must be pressed for releasing the transaction. The push-button as a mechanical element severely wears out over the years in use, so that the functionality of the push-button is not permanently guaranteed. Alternatively, the contactless chip card 1 could also be kept in a shielded wallet. Both approaches quite reliably prevent an unnoticed communication with the contactless card 1, but have turned out to be not suitable for daily use. As a complementary defensive measure it would also be conceivable to analyze the time behaviour of each transaction made by the payment terminal 23, in order to recognize in this way the temporal delay caused by a passing on via the network 27. The reliability of this measure, however, strongly depends on the quality of the network 27, which, however, with the ongoing technical development becomes constantly better."

In addition to the background information obtained for this patent, VerticalNews journalists also obtained the inventors' summary information for this patent: "The object of the present invention is therefore to show a method, a system and a portable data carrier, with which the releasing of a transaction between a portable data carrier and an end device is effected more cost-efficiently, more securely and more easily. The existing infrastructure between data carriers and end devices should be able to remain in use here if possible.

"According to the invention, the object is achieved by a method for releasing a transaction between a portable data carrier and an end device. For this purpose, the portable data carrier is first brought into an electromagnetic field. The EM field is generated here by the end device. The EM field serves as a power supply and for activating the portable data carrier. At first, no transactions are released between the portable data carrier and the end device. Or at least those transactions are not released, which include security-relevant information or data. In the next method step, mechanical oscillations are generated with the aid of a structure on the data carrier. These mechanical oscillations are subsequently captured in the portable data carrier by means of acceleration sensor. Then, the output signal of the acceleration sensor is evaluated or analyzed with regard to characteristic properties of the mechanical oscillation. As soon as a characteristic property of the oscillation has been recognized through the evaluation of the output signal, there is effected the releasing of the transaction by the portable data carrier. Alternatively to the releasing of transactions, the method can be employed to release a secured data area in the portable data carrier or to transmit security-critical information between end device and data carrier.

"A portable data carrier for the purposes of this application is, in principle, not of any predetermined form or configuration. In particular, a portable data carrier is understood to be a chip card, smart card, contactless card or in general a security token for example with an identification function. Alternative configurations for example as a mass memory card, e.g. .mu.SD card are also conceivable. Further, it is understood for the purposes of this application to be an electronic passport or different kind of identification medium, which contains security-critical information which should not generally be read out from the data carrier. For the broader purposes, the portable data carrier is a mobile phone with which transactions can be carried out with an end device, for example via a near-field communication. The mobile phone as a portable data carrier here has a near-field communication interface.

"An end device is understood to be any kind of communication device with which the portable data carrier can communicate in particular in a contactless fashion. A communication is effected by way of example with a reading device, also termed terminal, standardized according to ISO/IEC 14443. The end device is for example a point-of-sale terminal, POS terminal for short, or a pay machine with near-field communication interface.

"A transaction for the purposes of this application is understood to be a logical sequence of operations. A transaction is for example a payment transaction between a portable data carrier and an end device via a contactless interface. A transaction is alternatively also the readout of security-critical information, such as PIN numbers, personal data or general secrets, such as TAN numbers, passwords, and the like.

"For the purposes of this application an acceleration sensor is understood to be a sensor which ascertains the acceleration of a body, for example by determining the inertial force acting on a test mass. An acceleration sensor measures linear self-motions and accelerations and then triggers, on the basis of the measurement result, switching operations dependent on the self-motion in space. One type of an acceleration sensor is a rotation sensor which ascertains the rotational self-motion around an axis. Merely by way of example, the single-axis rotation sensor LY530AL and the three-axis acceleration sensor LIS344ALH from the company ST Microelectronics are stated as discrete electronic components here.

"Through the method of the invention, a portable data carrier is prevented in simple fashion from carrying out a transaction with an end device without the transaction having been previously released. With this method according to the invention a relay attack of the above-described type is very effectively prevented. This method is very cost-efficient, suitable for daily use and reliable.

"In an advantageous embodiment, the portable data carrier is set into self-oscillation through the mechanical excitation. Then this self-oscillation of the data carrier is captured in the form of acceleration and evaluated by means of the acceleration sensor. The advantage in this embodiment is to be seen in that an acceleration of the data carrier is readily evaluable even upon minimum excitation with mechanical oscillation.

"The characteristic property is preferably the time duration, the frequency and/or the amplitude of the mechanical oscillation. Accordingly, a transaction is only released when a target value of the characteristic property of the oscillation is exceeded, otherwise, the transaction is not released. Alternatively, there is advantageously checked whether a characteristic property of the oscillation lies in a strictly defined tolerance range. These characteristic properties can be captured very easily and securely for example with an evaluation unit.

"In a preferred embodiment, the generated mechanical oscillations fluctuate in frequency. Alternatively or additionally, several mechanical oscillations are superimposed. The fluctuation of the frequencies and/or the superimposition of oscillations are evaluated as a characteristic property in the portable data carrier. The evaluation unit ascertains on the basis of these fluctuations and superimpositions of the frequency, whether the right or authentic structure is present on the data carrier and decides on the releasing of the transaction. Therefore, the protection against relay attacks is substantially increased.

"In an alternative embodiment, the mechanical oscillations are generated by the data carrier being moved or rubbed with its structure on the outer surface of the end device. The oscillations arising from the friction are captured as accelerations in the portable data carrier and evaluated.

"Likewise provided according to the invention is a portable data carrier for data transmission with an end device. The data carrier has a card body. Into the card body there is incorporated an integrated circuit. Furthermore, in the interior at a top side of the card body there is mounted an acceleration sensor, the acceleration sensor providing output signals to the integrated circuit. Onto the top side of the card body there is applied a structure. By means of this structure, mechanical oscillations are generatable, thereby the data transmission being releasable, i.e. can be released.

"If the owner now runs for example his fingernail or a pen over the structure, mechanical oscillations are generated. These oscillations are detected, analyzed and evaluated in the interior of the card body. A transaction is released, as soon as the characteristic properties of the oscillation are beyond a target value or within a defined tolerance range. If the portable data carrier is a mobile phone, the structure is located preferably on the outside of the mobile phone housing. The capture, analysis and evaluation of the thus generated accelerations is effected either in a SIM card in the data carrier or in the mobile phone itself.

"The structure is incorporated for example by means of laser, milling machine or embossing somewhere in the surface of the card body. Preferably, the card body is laminated and the structure is embossed on the laminate. In this way, a structure can be realized very easily and cost-efficient.

"In a preferred embodiment the structure is arranged above the acceleration sensor. Thus it is possible for the generated mechanical oscillations to be ideally captured.

"In principle, the acceleration sensor can be placed anywhere in the card body. Preferably, the acceleration sensor is mounted in a gap of the card body at the top side of the card body, so that the mechanical oscillations can be captured very well.

"In an alternative embodiment, the acceleration sensor is incorporated into the integrated circuit, so that the manufacture of the portable data carrier according to the invention is cost-efficient.

"It is also conceivable to place the acceleration sensor individually per data carrier somewhere in the card body. Due to the different placement, equal mechanical oscillations are differently captured by the acceleration sensor, since in particular the card body itself causes an attenuation of the mechanical oscillations. These different amplitudes of the oscillations can be evaluated as a characteristic property and be a releasing criterion.

"In a preferred embodiment, the structure is configured individually per data carrier, so that the oscillations generatable by means of the structure are individual per data carrier. Such an individualization is for example the design of the form of the structure, e.g. circle, ellipse, triangle or square.

"Moreover, according to the invention it is proposed that the structure has grooves or consists of grooves. These grooves are arranged as lines, circles, or waves and form the structure. It is provided according to the invention that the grooves in a structure have different depths and the grooves distributed over the structure have different spacings.

"Through all these measures, fluctuations and superimpositions of the characteristic properties of the generated mechanical oscillations are obtained. It is preferably provided to configure the structures individually per data carrier. In this way, an individualization of the data carrier is achieved, a releasing is effected only when for the 'original' card body having the respective individual structure mechanical oscillations in specified tolerances can be captured and evaluated.

"Finally, according to the invention there is proposed a system for preventing a relay attack. The system comprises a portable data carrier of the already described type and an end device, whereby through the structure on the data carrier there are generated mechanical oscillations and the transaction between data carrier and end device is released only when a target value of a characteristic property of the mechanical oscillation is exceeded.

"The target value may be stored in a data memory in the data carrier and be retrieved during the evaluation of the characteristic property of the oscillation. Alternatively, a strictly defined tolerance range, for example a percentage deviation from the captured value of the characteristic property may be stored in the data memory."

URL and more information on this patent, see: Rankl, Wolfgang; Baldischweiler, Michael. Method, Portable Data Carrier, and System for Releasing a Transaction Using an Acceleration Sensor to Sense Mechanical Oscillations. U.S. Patent Number 8803658, filed June 30, 2010, and published online on August 12, 2014. Patent URL:

Keywords for this news article include: Electronics, Data Transmission, Giesecke & Devrient GmbH.

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Source: Electronics Newsweekly

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