HK1136379B - Secured housing - Google Patents

Abstract

The invention relates to a secured housing for electronic components, including a base plate (2), a lid (3), and side walls (4), defining a secured volume for the electronic components, and an opening detector (11). The side walls (4) allow for variations of the housing thickness between the base plate (2) and the lid (3). The opening detector (11) detects the opening of the housing only when the amplitude of the thickness variations exceeds a predetermined threshold.

Description

Technical field

The present invention relates to a secure enclosure to protect the elements contained therein, e.g. electronic circuits, from fraudulent manipulation.

State of the art

Data processed and stored in electronic circuits can be of a security-critical nature, particularly for financial transactions, where passwords or access codes are involved.

Many measures have been taken at the software level to counter attempts at unauthorised access to data. At the hardware level, the problem arises of restricting physical access to critical electronic parts containing data used for authentication, or processors on which programs are run. Many methods exist to prevent physical access to key parts of electronic devices, including coating an additional layer of substrate or hermetically sealed enclosures.

More recently, solutions have emerged that implement enclosures with walls containing a layer of conductive parts to detect any attempted intrusion. e.g. patent EP0924592 describes an electrical device protected from tampering by a layer of electrical elements whose alteration of conductive properties is detected and generates an alarm. e.g. patent EP1432031 describes a enclosure comprising several printed circuit boards, some of which are intended to detect similar tampering on the enclosure.

Improvements in the use of conductive circuits to detect tampering on boxes have extended to payment terminals, which contain an opening for the introduction of the card and therefore a priori present an additional weakness in the protection against physical access to electronic components.

The patent WO2005/08654 proposes to solve this problem by introducing electrical tracks into the wall of the housing around the opening to detect any gap, which is synonymous with attempted intrusion into the housing or manipulation of elements inside the housing.

Other solutions exist to detect the opening of the housing by means of a sensor, for example, it is possible to react to an electrical circuit failure caused by lifting the housing cover.

However, none of the proposed solutions can solve problems of volume or thickness adaptation. e.g. the boxes of payment terminals are often housed in a molded or injected plastic shell with poorly controlled thickness of the housing; this thickness varies, for example, in the event of shocks, manipulation or when the user presses the terminal keyboard, which tends to crush the cover and then lift it when the pressure is released.

The previously secure cases did not tolerate such small variations in volume or thickness, and any attempt to change the thickness, for example to force the case into a shell or during manipulation, often resulted in a false alarm or damage to the sensor.

US2006/049941 describes a secure housing for electronic components with side walls that allow for thickness variations.

Brief summary of the invention

One purpose of the present invention is to provide a secure enclosure for electronic components, and in particular for a payment terminal, free from known state-of-the-art limitations.

The present invention is intended in particular to provide a secure electronic circuit housing that can be housed in plastic shells with varying tolerances and that can be handled without special care to avoid triggering untimely alarms.

The enclosure of the invention shall allow an opening to access the electronic components inside when the alarm is deactivated.

These objectives are achieved by using a secure housing for electronic components according to claim 1.

The advantage of the proposed housing is that it can be housed in different possible volumes and is therefore compatible with different protective shells with a housing of varying thickness.

In addition, the unsealed case allows it to be opened to replace various components, including damaged or outdated components, such as an electric battery.

Brief description of the drawings

The invention will be better understood by illustrations provided by the figures in the annex representing different embodiments of the invention. Figure 1A shows a cross-section of a case showing the physical opening sensor of the case and the side walls.Figure 1B shows a cross-section of the case base plate on which plates forming part of the side walls are fixed.Figure 1C shows a view from the top of the case showing the physical opening sensor of the case and the outline of the side walls.Figure 2A shows a cross-section of another possible case variant, with some side walls being flexible.Figure 2B shows a cross-section of another case variant, with some of the side walls being flexible.Figure 3 shows an example of a possible detector and 4 examples of a physical detector module with some electronic detectors.

Detailed description and examples of how the invention is implemented

Figure 1A shows a cross-section of the secure enclosure, comprising a base plate 2, a cover 3, and side walls 4 formed of several plates fitting into each other. In a preferred variant, the base plate 2 and cover 3 are made up of printed circuit boards (PCBs). Electronic components are mounted on the inner surfaces of the base plate 2 and/or cover 3.However, care should be taken to avoid making electrical leads or components accessible from outside the housing where access to these components would compromise the security of protected data. In a preferred variant, base plate 2, cover 3 and/or sidewalls 4 are made up of multilayer PCBs including for example one or more internal layers for the components, a bulk layer for electromagnetic shielding, and an intrusion protection layer described below.A cable, e.g. flat cable 8 and connector 9 allow electrical connection between the electronic components on base plate 2 and the components on cover 3.

Figure 1A further shows a physical opening sensor of the case with two pieces 6 and 7 in contact with each other when the case is closed. One of the pieces, in the example the first solid contact piece 6 of the lid, may be made up in part of an elastic element such as a spring that holds it in compression against the other solid piece 7 of the base plate. When the spring that pushes one of the electrodes against the other to ensure contact within the allowed range of variation is at the end of the stroke, completely relaxed, the electrodes are no longer in contact and an electric current is interrupted, which can be detected by an electronic module described below.

The elastic element stroke in this example determines the possible variation in case thickness. In a preferred variant, the stroke is greater than 3 mm, preferably greater than 5 mm or even in the order of 10 mm or more.

A sensor opening detector using the above-described sensor, which operates like an electrical switch, has the advantage of being simple to implement and reliable in that the opening detection threshold of the case corresponds to the breakage of a physical contact. The transmission of the opening or closing state of the system can be managed by a digital input and output on a microprocessor.

The case opening detector of the invention includes, in addition to the physical sensor, an electronic module (not shown) to process the signals transmitted by the physical sensor and decide on an appropriate response. In the case of a physical sensor providing binary signals, the electronic module may consist of a digital logic circuit, e.g. a microcontroller. A more sophisticated analog processing module may be provided between the microcontroller and the physical sensor when the signal provided by the sensor consists of a finite measurement value (a capacity, a magnetic field, etc.).

The opening threshold at which a reaction is undertaken can be determined by the physical sensor itself, as in the example illustrated, or by the associated electronic module, particularly in the case of a physical sensor providing an output value with more than two possible states.

In the example shown in Figures 1A, 1B and 1C, the side walls are composed of several plates 4 welded or screwed to the base plate 2 which fit into several other plates welded or screwed to the lid 3. Such arrangement constitutes a chicane which prevents an object from entering the enclosure by removing the plates forming the wall.

The plates may be fixed to base plate 2 and lid 3 respectively in such a way that frictional forces keep them in a fixed resting position but still allow the plates to slide on each other. The generation of these frictional forces may be achieved either by acting on the thickness and position of the plates constituting the walls or by slightly tilting the plates constituting the side walls by fixing them to the base plate or lid in a slightly different vertical position from the first. In a preferential variant, the vertical position of the lid in relation to the base plate is determined by columns with one element related to the axis of the base plate and a second element connected to the lid,The two elements are screwed or fixed to each other by clips. It is also possible to attach the base plate and the cover to the half-shells of an unrepresented outer case, the assembly of the two half-shells being carried out by embedding the plates. The thickness of the case is determined in this case by the geometry of the housing between the two half-shells.

In a preferred design, the sidewalls 4 will be equipped with electrical tracks 10 whose ruptures or deformations can be detected in order to react in case of puncture or breakage of the housing. This may be for example a mesh circuit ( mesh circuit ) or a spiral circuit that will detect any attempt to puncture. Possible patterns of these circuits are illustrated in Figure 4.

Another possible design variant is to implement one or more flexible PCB sidewalls 4 which are hermetically fixed to base plate 2 and/or cover 3. In this variant the opening is done either on one side of the case if the plate is fixed to both base plate and cover or by de-solidising part of the plate e.g. to the cover, as shown in Figures 2A and 2B. In this case the ends of the plate will have electrical connectors acting as physical sensor parts 6 and 7.

The presence of electrical tracks 10 against drilling attempts may of course also apply to base plate 2 and/or lid 3; in this case a new substrate layer containing electrical tracks 10 will be required.

An aperture detector 11 can detect different forms of intrusion, including not only the unlawful opening of the housing, but also the piercing of the walls and/or prohibited manipulations, in order to decide whether a reaction is appropriate. It thus brings together one or more electronic components and/or modules for the analysis and interpretation of signals from one or more physical or software sensors. The response of the aperture detector 11 can be determined by software and includes, for example, the generation of an acoustic or visual alarm, the sending of a signal from a component to an interface, the temporary destruction of the wire, the removal of a message or a permanent block, the removal of a message or a permanent memory.

In the depicted execution mode, the aperture detector 11 comprises a microcontroller 14 to which the physical aperture sensor 16 of the case and a physical sensor 17 of detection of deterioration of electrical paths 10 are connected, the physical sensor 17 being a pathway connected to two inputs/outputs of the microcontroller 14. This microcontroller 14 interprets the signals transmitted by the physical sensors 16.17 in relation to the threshold values it has in memory 15 and generates an appropriate response. This reaction may for example consist of erasing a memory containing critical data 12, such as authentication data. In the case of non-binary physical sensors, such as the one described above, the microcontrollers 16 or 14 may be connected to the analogue module 13 or 14 by means of a wireless analogue module 13 or a wireless connector 13 which may be used to generate a number of other electronic devices.

The secure enclosure proposed by the invention is particularly suitable for payment terminals. In an unrepresented variant, a sidewall has an opening to allow the insertion of a chip card or magnetic card, with the card reader then being in the secure enclosure. Such a enclosure according to a preferred variant of the invention can detect the deviation of the opening through which the card is intended to be inserted and trigger an alarm, but it can nevertheless always be opened to replace parts such as a battery.

Connectors or cables may pass through the walls of the enclosure to connect a battery, an external card reader, an LED or LCD display, a keyboard or a loudspeaker. The invention also applies to enclosures secured on less than 6 sides, e.g. on 5 sides only; one of the sides may be open when mounted against a wall, or closed by a component.

List of references

(1) Base plate (2) Cover (4) Side walls (5) Means of attaching side walls to base plate and/or side walls to cover (6) First piece of physical opening sensor of the case (7) Second piece of physical opening sensor of the case (8) Flat electrical connection cable (9) Electrical connector pins on PCBs (10) Electrical intrusion detection tracks (e.g. mesh) (11) Opening detector (12) Memory containing critical data (13) Clock (14) Electronic module e.g. microcontroller (15) Decoder including opening values for the physical opening of the physical cap cap (10) Electrician's manual (1)

Claims (13)

1. Secured case for electronic components, comprising:

   - a basic board (2), a cover (3) and lateral walls (4) defining a secured volume for the electronic components, and

   - an opening detector of the case (11) comprising a physical sensor, wherein

   - the arrangement of the lateral walls (4) allow for variations in thickness of the case between said basic board (2) and said cover (3), in such a way as to be able to house said case in different protective shells presenting different possible inner volumes, and in that

   - said opening detector (11) reacts to the opening of the case only when the amplitude of the variations in thickness exceeds a determined threshold, in such a way as to avoid triggering untimely alarms, and characterized in that said opening detector of the case comprises an electronic module for processing signals transmitted by the physical sensor, and

   - the values of said threshold are predefined and entered into a programmable memory of the electronic module.
2. Secured case of claim 1, said opening detector comprising a physical sensor (16) and an electronic module (14), said physical sensor (16) generating signals that depend on the thickness of the case, the electronic module (14) processing the signals of said physical sensor to trigger a reaction when said threshold of variations has been exceeded.
3. Secured case of claim 1, said opening detector comprising a physical sensor (16) and an electronic module (14), said physical sensor (16) sending an electrical signal to said electronic module when said variation threshold has been crossed.
4. Secured case of claim 3, wherein the physical sensor (16) comprises an electrode (6) linked to the cover (3) and an electrode (7) linked to the basic board (2), an elastic element maintaining said electrodes in galvanic contact as long as said threshold of variations has not been exceeded.
5. Secured case of one of claims 2 to 4, wherein the physical sensor (16) is provided with contact parts forming an electric capacitor of which the variation in capacitance is used as a parameter for the detection.
6. Secured case of one of the preceding claims, wherein at least one lateral wall (4) comprises a printed circuit board mounted perpendicularly on the basic board (2) and a printed circuit board mounted perpendicularly on the cover (3), said printed circuit boards sliding one against the other.
7. Secured case of one of the preceding claims, certain lateral walls (4) being composed of several boards fixed to said basic board (2) that nests into several other boards themselves fixed to said cover (3).
8. Secured case of one of the preceding claims, certain lateral walls (4) being flexible.
9. Secured case of one of claims 1 to 3, wherein at least one portion of said basic board (2), of said cover (3) and/or of said lateral walls (4) is provided with electrical tracks (10) of which the ruptures or deformations, in particular during attempts to perforate through the case, are detected.
10. Secured case of one of the preceding claims, provided with an opening for the introduction of a chip card or of a magnetic card.
11. Secured case of one of the preceding claims, wherein said opening detector (11) being linked to an electronic module (14) able to act on a storage device of the system (12), in order for example to cause the erasing of the specification in the event of opening.
12. Secured case of claim 11, the electronic control circuit (11) being connected to a clock (13) tolerating the opening of the cover (3) at determined moments without this opening being interpreted as an intrusion by the opening detector.
13. Payment terminal comprising a case according to one of the preceding claims, the case being mounted in a plastic shell, the cover (3) being integral with an upper half-shell comprising a keypad and a screen, the basic board (2) being integral with a lower half-shell, the thickness of the case being defined by said shell.