Tamper resistant electronic assembly

Abstract

A tamper-resistant enclosure for protecting an electronic circuit, comprising: an outer casing formed of a rigid material; a plurality of nested aramid fibre enclosures disposed within the outer casing; at least one metal enclosure interspaced between the plurality of nested aramid fibre enclosures; and woven fibre sheet material enveloping the electronic circuit and filling a remaining internal volume of an inner-most enclosure. Also, a method for manufacturing a tamper resistant enclosure.

Description

TAMPER RESISTANT ELECTRONIC ASSEMBLYTechnical Field

[0001] This invention relates generally to tamper resistant electronic enclosures and to method for producing tamper resistant electronic enclosures. However, it will be appreciated that the invention is not limited to this particular field of use.Background

[0002] Any discussion of the background art throughout the specification should in no way be considered as an admission that such background art is prior art, nor that such background art is widely known or forms part of the common general knowledge in the field in Australia or worldwide as at the priority date of the present application.

[0003] All references, including any patents or patent applications, cited in this specification are hereby incorporated by reference, which means that it should be read and considered by the reader as part of this text. That the document, reference, patent application or patent cited in this text is not repeated in this text is merely for reasons of conciseness.

[0004] Tamper-proof electronics, also known as tamper-resistant or tamper-evident electronics, are designed to prevent unauthorized access, modification, or manipulation of electronic circuitry, for example to protect industrial trade secrets or military electronic equipment construction.

[0005] There are a range of solutions available for rendering electronics tamper proof including those based on secure enclosures with tamper evident seals. There are also approaches based on encapsulating electronics in materials such as epoxy resin for protection from physical impacts such as heat, moisture or pressure and to conceal components.

[0006] The application of encapsulation techniques, with resins, can be challenging at least due to issues associated with compression and decompression that can damage electronic components and thermal expansion and contraction that can compromise the resin and have other deleterious effects on its physical properties, some of which can result in the resin de-laminating or peeling away from the electronics.

[0007] With the above in mind there is a need for improved encapsulation techniques and materials that address or at least partially ameliorate the problems with existing encapsulation methods and encapsulated components.Summary

[0008] It is an object of the present invention to overcome or ameliorate at least one or more of the disadvantages of the prior art, or to provide a useful alternative.

[0009] Throughout this specification, unless the context requires otherwise, the words “comprise”, “comprises” and “comprising” will be understood to imply the inclusion of a stated step or element or group of steps or elements but not the exclusion of any other step or element or group of steps or elements. Any one of the terms “including” or “which includes” or “that includes” as used herein is also an open term that also means including at least the elements / features that follow the term, but not excluding others. Thus, “including” is synonymous with and means “comprising”.

[0010] Any one of the terms “including” or “which includes” or “that includes” as used herein is also an open term that also means including at least the elements / features that follow the term, but not excluding others. Thus, “including” is synonymous with and means “comprising”.

[0011] In the claims, as well as in the summary above and the description below, all transitional phrases such as “comprising”, “including”, “carrying”, “having”, “containing”, “involving”, “holding”, “composed of”, and the like are to be understood to be open-ended, i.e. , to mean “including but not limited to”. Only the transitional phrases “consisting of” and “consisting essentially of” alone shall be closed or semi-closed transitional phrases, respectively.

[0012] Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. The invention includes all such variation and modifications. The invention also includes all of the steps, features, formulations, and compounds referred to or indicated in the specification, individually or collectively and any and all combinations of any two or more of the steps or features.

[0013] Even though particular combinations of features are recited in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of possible implementations. In fact, many of these features may be combined in ways not specifically recited in the claims and / or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of possible implementations includes each dependent claim in combination with every other claim in the claim set.

[0014] According to a first aspect of the invention, there is provided a tamper-resistant enclosure for protecting an electronic circuit. The enclosure may comprise an external casing formed of a rigid material. The enclosure may further comprise a plurality of nested aramid fibre enclosures disposed within the external casing. The enclosure may further comprise at least one metal enclosure interspaced between the plurality of nested aramid fibre enclosures. The enclosure may further comprise woven fibre sheet material enveloping the electronic circuit and filling a remaining internal volume of an inner-most enclosure.

[0015] According to a particular arrangement of the first aspect, there is provided a tamper-resistant enclosure for protecting an electronic circuit, comprising: an outer casing formed of a rigid material;a plurality of nested aramid fibre enclosures disposed within the outer casing; at least one metal enclosure interspaced between the plurality of nested aramid fibre enclosures; and woven fibre sheet material enveloping the electronic circuit and filling a remaining internal volume of an inner-most enclosure.

[0016] The plurality of fibre material enclosures may comprise a high-strength synthetic fibre. The high-strength synthetic fibre may be an aramid fibre. The high-strength synthetic fibre may be a polyamide fibre.

[0017] The casing may be formed of a rigid material selected from the group consisting of metal, plastic, and a composite material. The one or more metal enclosures may be configured to provide electromagnetic shielding for the electronic circuit.

[0018] The fibre sheet material may comprise a woven aramid fibre configured to resist cutting and tampering.

[0019] The plurality of fibre material enclosures may be bonded to the one or more metal enclosures with an adhesive to prevent separation.

[0020] The fibre sheet material may be configured to fill at least 90% of the remaining airspace within the inner-most enclosure to prevent insertion of tampering tools.

[0021] The plurality of fibre material enclosures may comprise at least three nested fibre layers, each layer having a thickness of at least 0.5mm.

[0022] The one or more metal enclosures may comprise a corrosion-resistant metal selected from the group consisting of stainless steel, aluminium, copper, steel or stainless steel, nickel, nickel-iron alloy, tungsten, lead, depleted uranium, boron-steel, and titanium.

[0023] The fibre sheet material may be treated with a chemical coating to enhance resistance to moisture and degradation.

[0024] The tamper-resistant enclosure may further comprise a tamper-detection mechanism integrated into at least one of the plurality of fibre material enclosures, the tamper-detection mechanism configured to detect a breach of the enclosure. This may comprise a conductive fibre mesh configured to trigger an alert upon disruption. The tamper-detection mechanism may comprise a fibre optic cable woven into at least one of the plurality of fibre material enclosures, the fibre optic cable configured to detect tampering by disruption of light transmission.

[0025] The tamper-resistant enclosure may further comprise a destructive mechanism operatively coupled to the tamper-detection mechanism. The destructive mechanism may be configured to destroy at least a portion of the electronic circuit upon detection of a tampering attempt. The destructive mechanism may comprise a chemical agent release system configuredto release a corrosive substance onto the electronic circuit upon activation by the tamper-detection mechanism. The destructive mechanism may comprise an electrical overload circuit configured to deliver a high-voltage pulse to the electronic circuit to render it inoperable upon detection of tampering.

[0026] The destructive mechanism may comprise an explosive device configured to detonate and destroy at least a portion of the electronic circuit upon activation by the tamper-detection mechanism. The destructive mechanism may be embedded within the fibre sheet material such that on detonation, the fibre sheet material is converted to a plurality of ballistic fragments for destruction of the electronic circuit.

[0027] According to a second aspect of the present invention, there is provided a tamper-resistant enclosure for protecting an electronic circuit. The tarn per- resista nt enclosure may comprise an external casing formed of a rigid material. The tamper-resistant enclosure may further comprise a plurality of nested aramid fibre enclosures disposed within the external casing. The tamper-resistant enclosure may further comprise at least one metal enclosure interspaced between the plurality of nested aramid fibre enclosures. The tamper-resistant enclosure may further comprise woven fibre sheet material enveloping the electronic circuit and filling a remaining internal volume of an inner-most enclosure.

[0028] According to a particular arrangement of the second aspect, there is provided a tamper-resistant enclosure for protecting an electronic circuit, comprising: an external casing formed of a rigid material; a plurality of nested aramid fibre enclosures disposed within the external casing; at least one metal enclosure interspaced between the plurality of nested aramid fibre enclosures; and woven fibre sheet material enveloping the electronic circuit and filling a remaining internal volume of an inner-most enclosure.

[0029] The non-woven fibre sheet material may comprise an aramid fibre configured to provide tamper evidence upon attempted penetration.

[0030] The tamper-resistant enclosure may further comprise a tamper-detection circuit embedded within at least one of the plurality of nested aramid fibre enclosures, the tamper-detection circuit configured to signal a breach attempt.

[0031] According to a third aspect of the present invention, there is provided a method of protecting an electronic circuit within a tamper-resistant enclosure. The method may comprise the step of providing a casing. The method may comprise the further step of nesting a plurality of fibre material enclosures within the casing and within each other. The method may comprise the further step of interspacing one or more metal enclosures between the plurality of fibre material enclosures. The method may comprise the further step of placing the electronic circuit within an inner-most enclosure. The method may comprise the further step of covering the electronic circuit with a fibre sheet material that fills a remaining airspace within the inner-most enclosure.

[0032] According to a particular arrangement of the third aspect, there is provided a method of protecting an electronic circuit within a tamper-resistant enclosure, comprising: providing a casing; nesting a plurality of fibre material enclosures within the casing and within each other; interspacing one or more metal enclosures between the plurality of fibre material enclosures; placing the electronic circuit within an inner-most enclosure; and covering the electronic circuit with a fibre sheet material that fills a remaining airspace within the inner-most enclosure.

[0033] The method may comprise the further step of integrating a tamper-detection mechanism into at least one of the plurality of fibre material enclosures, wherein the tamper-detection mechanism is configured to detect and signal an attempt to breach the tamper-resistant enclosure.

[0034] According to a fourth aspect of the present invention, there is provided a tamper resistant assembly for electronic circuitry. The assembly may comprise an external casing. The assembly may further comprise a plurality of fibre material enclosures nested within the casing and within each other. The assembly may further comprise one or more metal enclosures nested within the casing and interspaced with the one or more fibre material enclosures. The assembly may further comprise a woven fibre material configured to cover components of the electronic circuit and fill a remaining airspace volume within an inner-most enclosure of the plurality of fibre material enclosures and the one or more metal enclosure.

[0035] According to a particular arrangement of the fourth aspect, there is provided a tamper resistant assembly for electronic circuitry, the assembly comprising: an external casing; a plurality of fibre material enclosures nested within the casing and within each other; one or more metal enclosures nested within the casing and interspaced with the one or more fibre material enclosures; a woven fibre material configured to cover components of the electronic circuit and fill a remaining airspace volume within an inner-most enclosure of the plurality of fibre material enclosures and the one or more metal enclosure.

[0036] The woven fibre material may be configured to fill at least 90% of the remaining airspace volume.

[0037] An inner-most fibre material enclosure may be configured to receive an electronic circuit board comprising a plurality of circuit elements.

[0038] According to a fifth aspect of the present invention, there is provided a tamper-resistant electronic assembly comprising: a circuit board including at least one electronic component;an epoxy polymer compound forming a casing around the circuit board; a first arrangement of a first aromatic polyamide fibre material located in the casing; and a second arrangement of a second aromatic polyamide fibre material located in the casing.

[0039] Whilst not being bound by this mode of effect, it is understood that the combination of features that form the assembly of the present invention mitigate problems caused by compression and decompression by conferring shock absorbing properties that do not unduly compromise the structural integrity of the assembly, and in particular, the epoxy polymer compound.

[0040] The circuit board may comprise a printed circuit board. The at least one electronic component may be selected from the list consisting of: a capacitor; a diode; a resistor; an inductor; a transistor; a transformer; a potentiometer; a switch; a sensor; an oscillator; a battery; a rectifier; a fuse; a relay; an LED; and a connector.

[0041] The epoxy polymer compound may comprise a high temperature moulding resin. The epoxy polymer compound may comprise a low viscosity of about 500-700 cps, 550-650 cps, 575-625 cps or about 600cps. The epoxy polymer compound may comprise a maximum operating temperature of about 240°-280°C, 245°-275°C, 250°-270°C, 255°-265°C or about 260°C. The epoxy polymer may be adapted to cure at room temperature. The epoxy polymer compound may comprise a liquid resin. The epoxy polymer compound may comprise a translucent resin. The epoxy polymer compound may comprise at least one feature from the list consisting of: hardness (shore) of about 50-70D, 55-65D or about 60D; thermal conductivity of about 1-2, 1.2-1.8, 1.4-1.6 or about 1.5 BTU in / hr. F°ft2; and thermal expansion of about 4.9-6, 5.2-5.7, 5.4-5.5 or about 5.4 (x105 / °C).

[0042] The epoxy polymer resin compound may comprise a low-viscosity epoxy encapsulant. The epoxy polymer resin compound may comprise a high temperature resistant epoxy. The epoxy polymer resin compound may comprise an electrical, moisture and chemical resistant epoxy. The epoxy polymer resin compound may comprise, for example, Durapot™ 861.

[0043] The first arrangement of a first aromatic polyamide fibre material may comprise a plurality of layers such as two, three or four layers. The number of layers may be selected based on the level of protection required for the tamper resistant electronic assembly.

[0044] The first arrangement of a first aromatic polyamide fibre material may be located adjacent to the at least one electronic component. The first arrangement of a first aromatic polyamide fibre material may be located adjacent and above the at least one electronic component sensor. The first arrangement of a first aromatic polyamide fibre material may be located adjacent and alongside the at least one electronic component. The first arrangement of a first aromatic polyamide fibre material may also be located adjacent and below the at least one electronic component.

[0045] Preferably, the first arrangement of a first aromatic polyamide fibre material is located to abut the at least one electronic component. The first arrangement of a first aromatic polyamide fibre material comprises a non-woven material. Preferably, the non-woven material comprises a random arrangement of fibres. The first arrangement of a first aromatic polyamide fibre material may also comprise a woven material. The first arrangement of a first aromatic polyamide fibre material may comprise a woven material tape or a woven material swatch. Preferably, first arrangement of a first aromatic polyamide fibre material comprises Kevlar™.

[0046] Preferably, the first arrangement of a first aromatic polyamide fibre material comprises a sheet material. The sheet material is elongate. The sheet material may be substantially planar or flat. The sheet material may also define at least one ridge or corrugation.

[0047] The first arrangement of aromatic polyamide fibre material comprises a generally “L” shaped cross section or an angle wherein the two parts of the “L” form a first leg and a second leg of the angle. The first and second legs are of the same length. The first arrangement of aromatic polyamide fibre material may be concertinaed.

[0048] The first arrangement of aromatic polyamide fibre material may comprise a plurality of different forms such as the sheet material and the generally “L” shaped cross section or angle. When the first arrangement of a first aromatic polyamide fibre material comprises the sheet material and the generally “L” shaped cross section or angle, the generally “L” shaped cross section or angle may be located above the sheet material.

[0049] The first arrangement of a first aromatic polyamide fibre material plurality of sheet material members may be arranged in a stacked configuration. The plurality of sheet material members may be arranged in an overlapping configuration.

[0050] The second arrangement of a second aromatic polyamide fibre material may comprise a plurality of layers such as two, three or four layers. The number of layers may be selected based on the level of protection required for the tamper resistant electronic assembly.

[0051] The second arrangement of a second aromatic polyamide fibre material may at least partially surround at least one of the first arrangement of a first aromatic polyamide fibre material and the circuit board. The second arrangement of a second aromatic polyamide fibre material may form an interlayer disposed within the casing. The second arrangement of a second aromatic polyamide fibre material may be in contact with at least one of the first arrangement of a first aromatic polyamide fibre material and the circuit board. The second arrangement of a second aromatic polyamide fibre material may define a box disposed within the casing that at least partially surrounds the first arrangement of a first aromatic polyamide fibre material and the circuit board.

[0052] The second arrangement of a second aromatic polyamide fibre material may comprise a woven material. The woven material may comprise a uniform arrangement of fibres. The wovenmaterial may be drapable. The woven material may be highly drapable. The second arrangement of a second aromatic polyamide fibre material may comprise Kevlar™. The second arrangement of a second aromatic polyamide fibre material comprises a tape. The second arrangement of a second aromatic polyamide fibre material defines a selvage edge. The second arrangement of a second aromatic polyamide fibre material may also comprise a woven tape or a woven swatch. The second arrangement of a second aromatic polyamide fibre material comprises a plurality of units arranged adjacently. The second arrangement of a second aromatic polyamide fibre material comprises a plurality of units arranged in an overlapping configuration.

[0053] The tamper-resistant electronic assembly may further comprise a radiation shield for the circuit board. The radiation shield for the circuit board is located inside the casing. The radiation shield for the circuit board at least partially surrounds the circuit board. The radiation shield for the circuit board may form an envelope around the circuit board. The radiation shield for the circuit board may comprise tungsten. The radiation shield for the circuit board may also be formed of a material selected from the list comprising: bismuth and iron. The radiation shield for the circuit board may form a box around the circuit board.

[0054] The radiation shield for the circuit board may also comprise a sheet material. The sheet material may have a thickness of at least about 0.05, 0.1 , 0.15, 0.2, 0.25. 0.3, 0.35, 0.4, 0.45 or at least 0.50mm.

[0055] The tamper-resistant electronic assembly may further comprise a third arrangement of a third aromatic polyamide fibre material. The third arrangement of a third aromatic polyamide fibre material may at least partially surround the second arrangement of a second aromatic polyamide fibre material. The third arrangement of a third aromatic polyamide fibre material may be in contact with the second arrangement of a second aromatic polyamide fibre material. The third arrangement of a third aromatic polyamide fibre material may form an interlayer or an inner-most enclosure disposed within the casing. The third arrangement of a third aromatic polyamide fibre material may form a plurality of interlayers disposed within the casing. The third arrangement of a third aromatic polyamide fibre material may define a box disposed within the casing that at least partially surrounds the second arrangement of a second aromatic polyamide fibre material. The third arrangement of a third aromatic polyamide fibre material may define a plurality of boxes disposed within the casing. The plurality of boxes may be provided in a nested arrangement.

[0056] The third arrangement of a third aromatic polyamide fibre material may comprise a non-woven material. The non-woven material may comprise a random arrangement of fibres. The third arrangement of a third aromatic polyamide fibre material may also comprise a woven material. The third arrangement of a third aromatic polyamide fibre material may comprise a woven material tape or a woven material swatch.

[0057] The third arrangement of a third aromatic polyamide fibre material may comprise Kevlar™. The third arrangement of a third aromatic polyamide fibre material may comprise atape. The third arrangement of a third aromatic polyamide fibre material may define a selvage edge. The third arrangement of a third aromatic polyamide fibre material may also comprise a woven tape or a woven swatch. The third arrangement of a third aromatic polyamide fibre material may comprise a plurality of units arranged adjacently. The third arrangement of a third aromatic polyamide fibre material comprises a plurality of units arranged in an overlapping configuration. The tamper-resistant electronic assembly may further comprise an enclosure that surrounds the other components to form an encasement. The enclosure may be formed of any suitable material and be of any shape and size suitable to enclose the assembly.

[0058] According to a sixth aspect or the present invention, there is provided a method of forming a tamper-resistant electronic assembly. The method may comprise the step of providing a circuit board including at least one electronic component. The method may comprise the further step of applying a first arrangement of a first aromatic polyamide fibre material to a location adjacent to the at least one electronic component. The method may comprise the further step of applying a second arrangement of a second aromatic polyamide fibre material to at least partially surround the first arrangement. The method may comprise the further step of applying an epoxy polymer compound to form a casing around the circuit board.

[0059] The first arrangement of a first aromatic polyamide fibre material may be applied to a location adjacent to and above the at least one electronic component. The first arrangement of a first aromatic polyamide fibre material may be applied to a location adjacent to and alongside the at least one electronic component. The first arrangement of a first aromatic polyamide fibre material may also be applied to a location adjacent and below the at least one electronic component. The first arrangement of a first aromatic polyamide fibre material may be applied to a location wherein it abuts the at least one electronic component.

[0060] The first arrangement of a first aromatic polyamide fibre material may be applied in the form of a sheet material. The sheet material may be substantially planar or flat. The sheet material may also define at least one ridge or corrugation.

[0061] The first arrangement of a first aromatic polyamide fibre material may also be applied in the form of a generally “L” shaped cross section, or an angle wherein the two parts of the “L” form a first leg and a second leg of the angle or may be concertinaed. The first arrangement of a first aromatic polyamide fibre material may also be applied in a plurality of different forms such as the sheet material and the generally “L” shaped cross section or angle or concertina.

[0062] Preferably, the first arrangement of a first aromatic polyamide fibre material may be applied as separate units arranged in a stacked configuration. The first arrangement of a first aromatic polyamide fibre material may be applied as separate units arranged in an overlapping configuration. The second arrangement of a second aromatic polyamide fibre material may be applied to form an interlayer or inner-most enclosure. The second arrangement of a secondaromatic polyamide fibre material may be applied to contact at least one of the first arrangement of a first aromatic polyamide fibre material and the circuit board.

[0063] The second arrangement of a second aromatic polyamide fibre material may be applied to form a box that at least partially surrounds the first arrangement of a first aromatic polyamide fibre material and the circuit board. The second arrangement of a second aromatic polyamide fibre material may be applied by draping the second aromatic polyamide fibre material over the first arrangement. The second arrangement of a second aromatic polyamide fibre material may be applied to form a plurality of units arranged adjacently. The second arrangement of a second aromatic polyamide fibre material may be applied to form a plurality of units arranged in an overlapping configuration.

[0064] The epoxy polymer compound may comprise a fluid. The epoxy polymer compound may be applied via a mould.

[0065] The method may further comprise the step of applying a radiation shield for the circuit board to at least partially surround the second arrangement. The radiation shield may be applied to form an envelope around the circuit board. The radiation shield may be applied to form a box around the circuit board.

[0066] The method may comprise the further step of applying a third arrangement of a third aromatic polyamide fibre material to at least partially surround the radiation shield. The third arrangement of a third aromatic polyamide fibre material may be applied to be in contact with the radiation shield. The third arrangement of a third aromatic polyamide fibre material may be applied to form an interlayer or inner-most enclosure disposed within the casing. The third arrangement of a third aromatic polyamide fibre material may be applied to form a plurality of interlayers disposed within the casing. Preferably, the third arrangement of a third aromatic polyamide fibre material may be applied to defines a box disposed within the casing. The third arrangement of a third aromatic polyamide fibre material may be applied to define a plurality of boxes disposed within the casing. The plurality of boxes may be provided in a nested arrangement.

[0067] In a further aspect of the present invention, there is provided a tamper-resistant electronic assembly comprising: a circuit board including at least one electronic component; an epoxy polymer compound forming a casing around the circuit board; a first arrangement of a first aromatic polyamide fibre material located in the casing; and a second arrangement of a second aromatic polyamide fibre material located in the casing.

[0068] The tamper-resistant electronic assembly may further comprise a radiation shield.

[0069] In a further aspect of the present invention, there is provided a method of forming a tamper-resistant electronic assembly, the method comprising the steps: providing a circuit board including at least one electronic component; applying a first arrangement of a first aromatic polyamide fibre material to a location adjacent to the at least one electronic component; applying a second arrangement of a second aromatic polyamide fibre material to at least partially surround the first arrangement; and applying an epoxy polymer compound to form a casing around the circuit board.

[0070] The method may further comprise the step of applying a radiation shield for the circuit board to at least partially surround the second arrangement.Brief Description of the Drawings

[0071] Notwithstanding any other forms which may fall within the scope of the present invention, a preferred embodiment / preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:Figure 1A is a side view of an enclosure that forms an encasement that surrounds a tamper resistant electronic assembly according to one embodiment of the first aspect of the present invention;Figure 2 is a partially exploded perspective view of the tamper resistant electronic assembly in Figure 1A depicting several of its key component parts;Figure 3 is a top view of the enclosure in Figure 1 , with the top section removed to reveal the tamper resistant electronic assembly therein;Figure 4A is a cut-away view through line A-A of Figure 1 looking into the tamper resistant enclosure from the side depicting the arrangement of internal component parts;Figure 4B depicts Figure 3 and includes two enlarged sections to show additional detail;Figure 4C shows a top-down view of the tamper resistant enclosure of Figure 1 showing a detail inset of the enclosure layers prior to epoxy filling;Figure 5 is a cut-away view through line A-A of Figure 1 looking into the tamper resistant enclosure from the side depicting the arrangement of internal component parts after epoxy filling;Figure 6 is a cut-away view of Figure 4A redrawn to show the extent of the epoxy polymer compound casing indicated by the hatched section; andFigures 7 to 11 diagrammatically represent a method of forming a tamper-resistant electronic assembly according to one embodiment of a second aspect of the present invention byreference to a series of perspective views of components of a tamper resistant electronic assembly.

[0072] In the drawings, like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention.Definitions

[0001] The following definitions are provided as general definitions and should in no way limit the scope of the present invention to those terms alone, but are put forth for a better understanding of the following description.

[0002] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. For the purposes of the present invention, additional terms are defined below. Furthermore, all definitions, as defined and used herein, should be understood to control and take precedence over dictionary definitions, definitions in documents incorporated by reference or other external sources, and / or ordinary meanings of the defined terms unless there is doubt as to the meaning of a particular term, in which case the common dictionary definition and / or common usage of the term will prevail.

[0003] For the purposes of the present invention, the following terms are defined below.

[0004] The articles “a” and “an” are used herein to refer to one or to more than one (i.e. , to at least one) of the grammatical object of the article. By way of example, “an element” refers to one element or more than one element.

[0005] The term “about” is used herein to refer to quantities that vary by as much as 30%, preferably by as much as 20%, and more preferably by as much as 10% to a reference quantity. The use of the word ‘about’ to qualify a number is merely an express indication that the number is not to be construed as a precise value.

[0006] Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, preferred methods and materials are described. It will be appreciated that the methods, apparatus and systems described herein may be implemented in a variety of ways and for a variety of purposes. The description here is by way of example only.

[0007] Also, various inventive concepts may be embodied as one or more methods, of which an example has been provided. The acts performed as part of the method may be ordered in anysuitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0008] The phrase “and / or”, as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0009] As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of” or “exactly one of”, or, when used in the claims, “consisting of’ will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e., “one or the other but not both”) when preceded by terms of exclusivity, such as “either”, “one of’, “only one of’, or “exactly one of”. “Consisting essentially of”, when used in the claims, shall have its ordinary meaning as used in the field of patent law.

[0010] As used herein in the specification and in the claims, the phrase “at least one”, in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B”, or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0011] For the purpose of this specification, where method steps are described in sequence, the sequence does not necessarily mean that the steps are to be carried out in chronological order in that sequence, unless there is no other logical manner of interpreting the sequence.

[0012] In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognise that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group.Detailed Description

[0013] Disclosed herein is a tamper-resistant enclosure for an electronic circuit, designed with multiple layers of protection. Broadly, the temper-resistant enclosure comprises a plurality of nested enclosures within an outer casing. The tamper-resistant enclosure comprises a plurality of the nested enclosures formed from a fibre material, and at least one metal enclosure interspaced between two of the plurality of fibre material enclosures.

[0014] The tamper-resistant enclosure further comprises a fibre sheet material covering or enveloping the components of the electronic circuit and its electrical components. The fibre enclosures and fibre sheet material may be a textile fibre or simply fibre. However, for improved tamper resistance, the fibre enclosures and fibre sheet material are formed from high-strength synthetic fibres, such as aramid fibres (aromatic polyamide fibres, e.g., Kevlar or Nomex) or other polyamide fibres (e.g., nylon), due to their durability, strength, and resistance to tampering. That is, natural fibre materials (e.g., cotton, wool) are not included as they do not provide a significant resistance to tampering and are otherwise susceptible to degradation over time.

[0015] Alternate embodiments may alternatively or additionally include non-aromatic polyamides such as polyamide fibre materials (e.g., nylon) which offer flexibility, abrasion resistance, and moderate strength, though are less robust than aramids for tamper resistance so if such fibre materials are used, the tamper-resistant enclosure would also include further layers or enclosures formed from aramid fibre material for acceptable tamper-resistance. In alternate embodiments, composite fibre materials may be used to form one or more of the nested enclosures by combining fibres materials such as, for example aramid or carbon fibre materials, with resins or other materials to form rigid or semi-rigid structures.

[0016] For the specific tamper-resistant application of the presently disclosed enclosure, aramid fibre materials are the most likely candidate for the fibre material enclosures and sheets, as it provides exceptional strength and resistance to physical tampering. However, a mix of fibre types or a less specialized polyamide, polyamide fibre or synthetic fibre may also be used depending upon the desired ability of the enclosure for tamper resistance.

[0017] In particular embodiments, the enclosure comprises an outer casing, generally comprising a rigid outer shell (for example a metal or rigid plastics material) to provide structural integrity and initial tamper resistance.

[0018] The enclosure comprises a plurality of nested enclosures formed from a fibre material which may comprise either layers of woven or non-woven aramid or polyamide fabrics, providing strength and flexibility which provide resistance to cutting, abrasion, and heat, making them ideal for preventing forced entry to the circuitry housed within the enclosure. Nested layers increase the difficulty of penetrating the enclosure, as each layer requires separate tampering efforts, each of which risks greater probability of damage to the electronic circuitry enclosed within the tamper-resistance enclosure such that, even should a motivated malicious actor achieve access to the enclosed electronic circuitry, such circuitry would be damaged beyond usefulness or reverse engineering efforts.

[0019] The plurality of fibre material enclosures may preferably be formed from a high-strength synthetic fibre comprising, for example, an aramid fibre, a polyamide fibre, a composing fibre material, or the like.

[0020] The tamper-resistant enclosure further comprises one or more metal enclosures interspaced between the fibre material enclosures. Such metal enclosure layers add to the enclosure and additional temper resistance requiring additional tools and techniques which a malicious actor must employ to gain access to further nested enclosure layers. The one or more metal layers also provides electromagnetic shielding (for example, to provide resistance against electromagnetic (EMI) or RF inspection or attacks), and further tamper resistance. Interspacing the one or more metal layers with the plurality of fibre enclosures creates a hybrid structure that balances weight, strength, and protection.

[0021] In particular arrangements, the one or more metal enclosure layers may be bonded to adjacent fibre material enclosure layers using strong adhesives to prevent easy separation. Epoxy or resin systems to bond successive nested enclosures or layers can significantly enhance structural integrity and tamper resistance of the enclosure.

[0022] Furthermore, the enclosure comprises fibre sheets formed from a fibre sheet material which are used to cover and enclose the circuit components of the circuit board encased within the enclosure. The fibre sheet material is also used to fill the airspace of the inner-most enclosure housing the circuit board. The fibre sheets provide multiple advantages, for example to shield delicate circuit components from shock and vibration and to provide evidence of tampering since fibre materials like aramid are difficult to cut or remove without leaving visible damage. The fibre sheets also provide a space-filling role to substantially fill the remaining volume of the inner-most enclosure and which also will prevent insertion of tools or probes by filling voids, thus further enhancing security against invasive tampering of the electronic circuit housed within the enclosure. The fibre sheet material may comprise a non-woven aramid felt configured to resist cutting and tampering.

[0023] The fibre sheets encompassing and / or abutting the circuitry and filling the remaining airspace volume of the inner most enclosure may be formed from a non-oven aramid material.For example, a non-woven aramid felt or foam infused with aramid fibres may be used which is useful to maximise coverage of the circuit components and filling of the remaining airspace volume, while and making probing of the housed circuitry difficult without adding significant weight.

[0024] Aramid fibre is an aromatic polyamide, known for high tensile strength, heat resistance, and cut resistance (e.g., Kevlar for strength, Nomex for fire resistance). These materials are ideal for tamper resistance due to their difficulty to cut or penetrate as well as providing resistance to heat. Aramid fibres (e.g., Kevlar, Nomex) are commonly used in security applications like bulletproof vests or cut-resistant cables since they offer high tensile strength (stronger than steel by weight) and are lightweight, allowing multiple nested layers without excessive weight to the tamper-resistant enclosure.

[0025] Polyamide fibres (e.g., nylon) may also be used in particular embodiments that offer a more flexible and less expensive alternative to aramid fibre materials, suitable for less demanding applications. Such polyamide fibres offer good abrasion resistance but may be less effective against cutting or extreme conditions.

[0026] Composite fibres may also be used to provide rigidity to the nested fibre enclosures, for example the fibre materials from which the nested enclosures are formed may be embedded in a resin matrix, creating a composite material with enhanced strength and tamper resistance.

[0027] In particular arrangements, the fibre materials forming the nested enclosures and for filling of the remining volume of the inner-most enclosure may be treated for resistance to moisture, chemicals, or UV degradation, especially if the enclosure is expected to be exposed to harsh environments.

[0028] In specific embodiments, tamper resistance of the circuit board housed within the enclosure is the primary goal, the use aramid fibres (e.g., Kevlar for strength, Nomex for thermal resistance) for both enclosures and sheet material is preferred.

[0029] In further embodiments, for example to offer a lower cost solution or a solution providing lesser robust tamper resistance, e.g., for less critical circuity, nylon materials (or the like) for less critical layers maybe preferred, whilst still providing the option for aramids materials to be prioritized for outer or high-risk layers of the enclosure.

[0030] Referring to the Figures, depicting a particular embodiment of a temper-resistant enclosure 100, Figure 1 depicts an external casing 10 within which a plurality of fibre material enclosures and at least one metal enclosure layers are nested as shown in Figure 2 and 3. Casing 10 is formed of a rigid material selected from the group consisting of, for example, metal, plastic, and a composite material, or the like.

[0031] Figure 2 shows an exploded depiction of a particular embodiment of enclosure 100 including nested fibre material enclosures 26a, 26b, and 26c and, in this embodiment, a single metal enclosure layer 24. It will be appreciated that alternative embodiments may include a different number of fibre material enclosures 26 metal enclosure layers 24. Enclosure 100 is adapted to house a circuit board 12 that supports several electronic components including 13a - 13e within an inner-most nested enclosure 22. Inner-most enclosure 22 is preferable a further nested fibre material enclosure. To assist understanding and conceptualisation of the present invention, the enclosure layers 24 and 26 of enclosure 100 are depicted in the figures as being a box which is open at the top. I In practice, using enclosure layers 16, 22, and 24 which are open at one side (e.g., the top) may be useful for ease of manufacturing purposes, since each enclosure layer may be formed from a flat sheet folded to form an open box within which subsequent enclosure layers may be easily nested and may further be epoxy bonded together using a liquid epoxy resin to fill any remaining airspace between each of the nested enclosure layers. In particular embodiments, enclosure 22 may further include an opening or cutout 22a (see Figure 11) to permit electrical cables 13a to pass therethrough to provide electrical connections to the electronic circuit components 13 included on electrical circuit board 12. Alternatively, at least one surface of enclosure 22 may present incomplete encapsulation (not shown) of the interior components to permit electrical wiring 13a to pass through enclosure 22 to provide electrical connections to components 13.

[0032] However, in further embodiments, it will be readily appreciated that fully enclosed enclosure layers 24 and 26 which completely surround the enclosure(s) nested within each enclosure may be utilised to ensure that there is no preferentially easier direction by which access to the electronic circuitry may be revealed by a malicious actor. In the product destruction testing efforts described below, having the nested enclosure layers being open on top did not affect the tamper resistance because of the thick swatch weave of the nested fibre material enclosure layers and fibre material sheets surrounding the circuit board and inner-most enclosure 22 in conjunction with the airspace volume fill using the liquid epoxy resin. The fibre material enclosure layers 26a, 26b, and 26c of the example structure of enclosure 100 depicted in the figures maintain the shape of the encasing. Additionally, the fibres of each of the nested fibre material enclosures 16 may be preferentially provided such that each layer presents with fibres running in different directions from enclosure 22 act as a binder protection. When resin 30 is applied, fibre material layers 26a, 26b and 26c bind or squash under pressure against innermost enclosure 22. Having the extra layers 26a - 26c allows insertion of the at least one metal enclosure layers 24, preferably formed from tungsten to provide shielding protection for the electronic circuitry from radiation vector inspection or attack, electrical interference to the electronic circuitry and mechanical resistance to attack due to the tensile strength of the metal layer. Particularly advantageous is to nest the at least one metal layer between the fibre material enclosure layers to provide further difficulty of removal of the metal enclosure layer 24.

[0033] Liquid epoxy resin is preferentially a low-viscosity epoxy selected to provide one or more of: excellent penetration and encapsulant properties to provide deep penetration into small spaces; high temperature resistance; electrical resistance; moisture resistance; and / or chemical resistant epoxy.

[0034] Figure 3 shows a top view of the enclosure 100, showing the nested fibre material and one or more metal layers nested therein and the inner-most enclosure layer 22 adapted to receive the electronic circuitry to be protected by enclosure 100. A liquid epoxy compound is used to fill the interior volume of casing 10 and to provide epoxy bonding between enclosure 22, the plurality of fibre material enclosure layers 16 and at least one metal layer 24 within casing 10. An example of a particular suitable epoxy liquid is Coltronics Duropot 861. Once applied, the epoxy liquid that forms a casing 30 (see Figure 5) around the circuit board 12 and other parts of the enclosure 100 that are described in more detail below. Epoxy liquid fill casing 30 provides the further advantage of urging the fibre material sheets with inner-most enclosure 22 together under pressure to form a tighter fibre material matrix to prevent access to the electronic circuitry encased within.

[0035] Referring to Figure 2, for example, in a particular embodiment of a tamper-resistant enclosure 100 for protecting an electronic circuit, the enclosure 100 comprises an outer casing 10 formed of a rigid material. Enclosure 100 further comprises a plurality of nested aramid fiber enclosures 26 (e.g., enclosures 26a, 26b, and 26c) disposed within the outer casing 10. Enclosure 100 further comprises at least one metal enclosure 24 nested within casing 10 and preferably interspaced between two of the nested aramid fiber enclosures 26, for example, as shown in Figure 4C. An inner-most enclosure 22 is nested within the fibre material 16 and metal enclosure 24 layers. Inner-most enclosure 22 is adapted to receive and house an electronic circuit board 12 comprising a plurality of electronic circuit components 13 (see, for example, components 13a - 13f of Figure 7).

[0036] In use, to protect a particular electronic circuit from tampering, the tamper-resistant enclosure 100 further comprises a fibre sheet material 16 covering or enveloping the components of the electronic circuit board 12 and its electrical components 13. The fibre enclosures 26 and fibre sheet material 16 may be a textile fibre or simply fibre. Fibre sheet material may be either a woven or non-woven fibre material for example a polyamide fibre material. Fibre sheet material 16 is preferentially formed from a veil weave which is not woven but rather is bonded together in a random fibre matrix. The non-woven construction allows a resin-rich surface that preferentially bonds with epoxy resin casing 30 to increase chemical stability and reduces the risk of micro-cracks forming in the composite surface / interface. Random matrix fibre material sheeting 16 has the advantages of excellent formability, drape and wets out evenly which provide advantages for use adjacent to the electronic circuitry for excellent moulding to and encasement of the electronic components 13. Fibre material enclosures 26 are not required to be of a similar random matrix construction and a heavy-duty weave fibre material can be used to great effect providing significant resistance to mechanical destruction to prevent tampering.

[0037] Fibre sheet material may comprise a woven fiber sheet material enveloping the electronic circuit and filling a remaining internal volume of an inner-most enclosure. The fibre sheet material is configured to fill at least 90% of the remaining airspace within the inner-most enclosure 22 to prevent insertion of tampering tools.

[0038] Figure 4A shows a cut-away view of tamper resistant enclosure 100 through line A - A of Figure 1 (looking into the cut-away enclosure 100) when in use to protect an electronic circuit 12 within inner-most enclosure layer 22. Circuit board 12 and the electronic circuitry included thereon are overlaid and generally surrounded by a plurality of horizontal portions 16 of fibre sheet material (e.g., fibre sheet material layers 16a - 16f). Horizontal layers 16a - 16f are generally overlapping so that substantially the whole of the component circuitry and the form of the electrical interconnected made between the components by circuit board 12 are occluded by the fibre sheet material. In practice, vertical portions 18 of fibre sheet material (e.g., fibre sheet material posts 18a and 18b) either to form a barrier between vertical or tall circuit components and / or to provide a support for additional fibre material 20 to substantially fill the remaining internal volume of inner-most enclosure 22. The fibre sheet material is configured to fill at least 90% of the remaining airspace within the inner-most enclosure 22 to prevent insertion of tampering tools. Fibre sheets 16 may be formed from woven or non-woven aramid fibre material sheets. In this particular stage filling in the airspace volume of inner-most enclosure 22 can be a woven or non-woven because when the liquid epoxy resin encasing 30 is applied, the fibre materials are urged together under pressure to form a tight fibre material matrix which is more resistant to separation of the individual layers by a malicious actor attempting to gain access to the electronic circuitry housed within.

[0039] Thus, in use, fibre material portions are included and arranged to protect the circuit components including a plurality of horizontally oriented units 16a - 16g arranged to overlap with each other and located adjacent to and above electronic components 13a - 13e, a plurality of vertically oriented units 18a, 18b located adjacent to and between adjacent tall / vertically extending electronic, and a plurality of further fibre material sheets 20, arranged to overlap with each other and located adjacent to and above electronic components 13a - 13e to substantially fill the remaining internal volume (at least 90%) of inner-most enclosure 22. Further fibre material sheets 20 are advantageously provided in angled or concertinaed sheets 20 to more completely fill the remaining airspace volume of inner-most enclosure 22. Inner-most enclosure 22 surrounds or forms a box around the plurality of sheet material units 16a - 16g, 13a - 13e, 18a, 18b and 20.

[0040] Figures 4B and 4C show detail views of Figure 4A to clarify the configuration and order of the enclosure layers 24 and 26 surrounding inner-most enclosure 22 within which is housed the electronic circuitry 12. In the present embodiments of the tamper resistant enclosure 100, multiple enclosure layers 24 and 26 comprise open enclosures (i.e., which are not enclosed at the top). In the present embodiment, inner-most enclosure 22 is open at two opposing sides. This configuration enables ease of fabrication of the enclosure 22 and to further enable application of epoxy fill liquid both internally to enclosure 22 to encase the electronic circuitry as well as providing epoxy bonding with fibre material enclosure layer 26c.

[0041] Enclosure 100 comprises a plurality of nested fibre material enclosures 26 which surround the innermost fibre material layer 22. In particular embodiments, enclosure 100 comprises at least three nested material fiber enclosure layers, each layer having a thickness of at least 0.5mm. Fibre material enclosures 26 may optionally be treated with a chemical coating to enhance resistance to moisture and degradation.

[0042] Enclosure 100 further comprises at least one metal enclosure layer 24 which is disposed between two fibre material enclosures 26. Metal enclosure 24 may preferably provide radiation shielding against electromagnetic (EMI), RF radiation, radioactive radiation, and / or ionising radiation to prevent non-invasive / non-destructive imaging or non-invasive / non-destructive inspection of the form of the electronic circuitry housed within inner-most fibre material enclosure 22. Metal enclosure layer may preferably be formed from tungsten, however alternative metals may also be used, including, for example, stainless steel, aluminium, copper, steel or stainless steel, nickel, nickel-iron alloy, tungsten, lead, bismuth, depleted uranium, boron-steel, and titanium or other suitable metal material as would be readily appreciated by the skilled addressee.

[0043] The one or more metal enclosures 24 may comprise a corrosion-resistant metal selected from the group consisting of stainless steel, bismuth, aluminium, and titanium.

[0044] In particular embodiments, the one or more metal enclosures 24 may be chemically / adhesively bonded to one or more of the adjacent fibre material enclosures 26 to prevent separation ad provide improved tamper resistance.

[0045] It will be appreciated that more than one metal layer 24 may be included with tamper-resistant enclosure 100. Each of the more than one metal enclosures 24 may be formed from a different metal material to perform unique but cooperative functions. For example, a first metal layer may be provided configured for EMI / RF radiation shielding and may be selected from, for example copper (best conductivity), stainless steel (durable, moderate shielding), aluminium (lightweight, cost-effective), or mu-metal (magnetic fields). Further metal enclosure layer(s) may be provided configured for shielding of ionising radiation and may be selected from, for example, lead (gamma shielding, cost-effective), tungsten (gamma shielding, compact), stainless steel (beta radiation shielding, some gamma shielding), or boron-containing alloys (neutron radiation shielding). Further metal enclosure layer(s) may be provided for additional structural integrity of the enclosure 100, for example stainless steel or tungsten. Additional metal enclosure layers may also be provided for additional purposes according to requirements.

[0046] Enclosure 100 further comprises an external enclosure 10 that completely surrounds the other enclosure layers to form aa tamper resistant enclosure 100 as described herein.Tamper Detection

[0047] In further embodiments, the tamper resistant enclosure 100 may optionally include additional security features.

[0048] For example, enclosure 100 may optionally comprise a tamper-detection mechanism which may be interspaced between one or more of the fibre material enclosure layers 26 and / or metal enclosure layer 24 and / or may be integrated into at least one of the plurality of fiber material enclosures. 26. The tamper-detection mechanism may be configured to detect a breach or attempted breach of enclosure 100. In further embodiments, enclosure 100 may further comprise a communications module (not shown) which may be operatively coupled with the tamper-detection mechanism such that if a breach or attempted breach is detected by a malicious actor, the communications module may communicate an alert to a predetermined friendly actor via an appropriate available communications protocol, for example over any available cellular networks or the like.

[0049] Particular, non-exhaustive, examples of a suitable tamper-detection mechanism may comprise:• A conductive fiber mesh (not shown) surrounding or incorporated within a suitable enclosure layer 24, 26 configured to trigger an alert upon disruption.• A fibre optic cable (not shown) woven into at least one of the plurality of fiber material enclosures 26, the fibre optic cable configured to detect tampering by disruption of light transmission through the fibre optic cable.• A pressure sensor within casing 10 operatively coupled with a suitable communications module to detect movement, or altitude changes, or impacts to enclosure 100 which may indicate activity by a malicious actor attempting to gain access to the enclosed circuitry.• A movement or tracking sensor within casing 10 operatively coupled with a suitable communications module to identify and locate movement of the enclosure by a likely malicious actor to locate where access to enclosure 100 may be attempted or where reverse engineering activities may be taking place.

[0050] Alternative tamper detection methods may also be used as would be readily appreciated by the skilled addressee.Circuit Board Destruction

[0051] In further embodiments, the tamper resistant enclosure 100 may optionally include a destructive mechanism as an ultimate protection against tampering or inspection of the electronic circuitry enclosed within enclosure 100. For example, enclosure 100 may optionally further comprise a destructive mechanism (not shown) operatively coupled to the tamper-detection mechanism. The destructive mechanism is configured to destroy at least a portion of the electronic circuit upon detection of a tampering attempt.

[0052] Particular, non-exhaustive, examples of a suitable destructive mechanism may comprise:• A chemical agent release system configured to release a corrosive substance onto the electronic circuit upon activation by the tamper-detection mechanism.In this embodiment, the one or more metal enclosure layers 24 may be chosen from a corrosion resistant metal, for example copper, stainless steel, and aluminium which are resistant to many corrosive substances, ensuring the enclosure remains intact during activation of the chemical destructive agent.• An electrical overload circuit configured to deliver a high-voltage pulse to the electronic circuit to render it inoperable upon detection of tampering.In this embodiment, the one or more metal enclosure layers 24 may be chosen from an electrically conductive metal, for example copper or aluminium to electrically conduct the overload pulse effectively, ensuring circuit destruction without compromising the shielding of enclosure 100.• An explosive device, for example, Semtex of the like, configured to detonate and destroy at least a portion of the electronic circuit upon activation by the tamper-detection mechanism.In this embodiment, the one or more metal enclosure layers 24 may be chosen from a high strength metal, for example stainless steel or tungsten to provide structural integrity to enclosure 100 to contain a controlled explosion and preventing unintended damage to the surroundings.

[0053] In particular embodiments, the explosive destructive mechanism is embedded within the fiber sheet material 16, or 18 such that, on detonation, the fibre sheet material is converted to a plurality of ballistic fragments for destruction of the electronic circuitry including electronic components 13 and circuit board 12.Method of Manufacture

[0054] In a further embodiment of the present invention, there is provided a method of protecting an electronic circuit 12 within a tamper-resistant enclosure 100. The method may comprise providing a casing 10. The method may further comprise nesting a plurality of fibre material enclosures 26 within the casing 10 and within each other. The method may further comprise interspacing one or more metal enclosures 24 between the plurality of fibre material enclosures26. The method may further comprise placing the electronic circuit 12 within an inner-most enclosure 22. The method may further comprise covering the electronic circuit with a fibre sheet material 16, 18 that fills a remaining airspace within the inner-most enclosure 22.

[0055] The method may further comprise integrating a tamper-detection mechanism into at least one of the plurality of fibre material enclosures 26, wherein the tamper-detection mechanism is configured to detect and signal an attempt to breach the tamper-resistant enclosure 100.

[0056] A method of forming a particular embodiment of a tamper resistant electronic enclosure 100 is depicted in Figures 6, to 11. The method according to the embodiment comprises providing a circuit board 12 including several electronic component including components 13, applying a plurality of aromatic polyamide fibre material in the form of a plurality of non-woven aramid sheet material units including a set of horizontally oriented units 16a - 16d arranged to overlap with each other and located adjacent to and above some of the electronic components (see Figure 7), a set of vertically oriented units 18a - 18e located adjacent to and between adjacent electronic components 13a - 13h (see Figure 8), another set of horizontally oriented units 16 arranged to overlap with each other and located adjacent to and above some of the electronic components (see Figure 9) and a set of concertinaed fibre sheets 120, arranged to overlap with each other and located adjacent to and above the electronic components (see Figure 10).

[0057] The method further comprises the step of applying a second arrangement of a second aromatic polyamide fibre material in the form of a woven aramid material enclosure 22 to surround the first arrangement forming a boxed arrangement (see Figure 11) wherein enclosure 22 forms the inner-most enclosure of the tamper resistant enclosure 100 described above.

[0058] The method further comprises the step of applying a plurality of fibre material layers 26 and at least one metal layer (e.g., as a radiation shield, for example tungsten) between two fibre material layers 26. The enclosure 100 is assembled similarly to Figure 2 within an external rigid casing 10. Once enclosure layers 24 and 26 are nested within casing 10, and inner-most enclosure 22 is nested within the inner fibre material enclosure layer 26c a liquid epoxy polymer compound in liquid form applied by pouring into the casing 10 to completely encase the fibre material enclosure layers 26 and the at least one metal enclosure layer 24 around the circuit board 12 and all other components within external casing 10. As can be seen in Figure 5, the liquid epoxy 30 (depicted by diagonal hatched lines) completely fills any remaining volume within inner-most enclosure 22 to completely surround the electronic circuitry 12 and electronic components 16 as well as fibre material fill 120 within enclosure 22. Epoxy 30 also fills any remaining airspace volume within and between enclosure layers 22, 24, and 26 to bond each layer to its adjacent layer(s) and provide additional resistance to tampering with any of the enclosure layers or, especially, to prevent separation of the intermediate enclosure layers 22, 24, and 26 to further protect electronic circuitry housed within enclosure 22.

[0059] Manufacture of the tamper resistant enclosure in this manner, that is, commencing from the circuit board 12 to be protected, ensures that the enclosure 100 is specifically adapted to the shape, form and composition of the electrical circuit board 12 and specific electrical components 13 such that the enclosure 100 it inherently adaptable to the specific size and shape of the circuitry to be protected.

[0060] In a particular method of constructing the tamper resistant enclosure, there is provided the steps of:(a) forming an enclosure 22 being open to the top and two opposing sides and having a lid adapted to close enclosure 22 to the top;(b) locating a circuit board 12 within enclosure 22;(c) covering circuit components of circuit board 12 with a plurality of overlapping fibre material sheets;(d) covering overlapping fibre material sheets with concertinaed fibre sheets to fill a remaining volume within enclosure 22;(e) locating enclosure 22 within a plurality of fibre material enclosures and at least one metal enclosure, wherein:(i) the plurality of fibre material enclosures and at least one metal enclosure are open to the top; and(ii) the at least one metal enclosure(s) and located between two of the plurality of fibre material enclosures;(f) locating the nested construction of enclosure 22 and the plurality of fibre material enclosures and at least one metal enclosure within a casing 10;(g) filling the interior volume of enclosure 22 with an epoxy liquid 30 to encase the electronic circuitry, fibre sheets and concertinaed fibre sheets within the epoxy liquid;(h) closing the top / lid of enclosure 22 to encase the epoxy-filled interior volume of enclosure 22;(i) filling the remining internal volume of the casing 10 with epoxy liquid to completely encase enclosure 22, the plurality of fibre material enclosures 16 and the at least one metal enclosure 24 and to provide epoxy bonding between the nested enclosure layers; and(j) enclosing casing 10 to provide the tamper resistant enclosure 100.Destructive Testing

[0061] Trials of example prototype enclosures 100 have been conducted to simulate extreme hazard conditions such as extensive mechanical workshop, shooting range, and laboratory trials, to determine the tamper resistance of the enclosure 100. High-powered tools including diamond-tipped drill bits were used to attempt to breach the casing by direct mechanical force, while advanced scanning methods also confirmed that no vulnerabilities to radiation were observed.

[0062] Across all tested scenarios, only cosmetic damage to the enclosure 100 was observed. No access to the circuitry housed within was gained and the electronic components remained fully shielded. Indeed, the diamond drill bits used for the testing were damaged in the process, highlighting the resilience of the enclosure 100.

[0063] All simulated attempts to expose or reverse engineer the protected electronic circuitry consistently failed without destroying the protected circuitry itself. Thus, it was demonstrated that enclosure 100 provided significant resistant to intellectual property theft residing in the protected circuitry thus providing an effective solution for safeguarding sensitive electronics, proprietary technologies, and confidential information from for example, industrial espionage, or exposure of military hardware and knowhow on the battlefield.

[0064] During testing, the following properties of the example prototype enclosure 100 were identified:Additional Embodiments

[0065] Additional embodiments of tamper resistant enclosure 100 may be provided by selection of particular properties of the plurality of fibre material enclosure layers 26 and or the one or more metal enclosure layers 24. For example, appropriate selection of the nested enclosure materials may provide a tamper resistant enclosure 100 suitable for, heat shielding, impact protection, crumple zone protection, tracking, or the like.

[0066] Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention. The present invention is not to be limited in scope by any of the specific embodiments described herein. These embodiments are intended for the purpose of exemplification only. Functionally equivalent products, formulations and methods are clearly within the scope of the invention as described herein. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

[0067] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some exampleembodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0068] Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

[0069] The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0070] Reference to positional descriptions and spatially relative terms), such as “inner”, “outer”, “beneath”, “below”, “lower”, “above”, “upper” and the like, are to be taken in context of the embodiments depicted in the figures, and are not to be taken as limiting the invention to the literal interpretation of the term but rather as would be understood by the skilled addressee.

[0071] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer, or section. Terms such as “first”, “second”, and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the example embodiments.

[0072] It will be understood that when an element is referred to as being “on”, “engaged”, “connected” or “coupled” to another element / layer, it may be directly on, engaged, connected, or coupled to the other element / layer or intervening elements / layers may be present. Other words used to describe the relationship between elements / layers should be interpreted in a like fashion (e.g., “between”, “adjacent”). As used herein the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0073] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. The use of the singular includes the plural unless specifically stated otherwise. As used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprise”, “comprises”, “comprising”, “including”, and “having”, or variations thereof are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.Embodiments

[0074] Reference throughout this specification to “one embodiment”, “an embodiment”, “one arrangement” or “an arrangement” means that a particular feature, structure or characteristic described in connection with the embodiment / arrangement is included in at least one embodiment / arrangement of the present invention. Thus, appearances of the phrases “in one embodiment / arrangement” or “in an embodiment / arrangement” in various places throughout this specification are not necessarily all referring to the same embodiment / arrangement, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments / arrangements.

[0075] Similarly, it should be appreciated that in the above description of example embodiments / arrangements of the invention, various features of the invention are sometimes grouped together in a single embodiment / arrangement, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment / arrangement. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment / arrangement of this invention.

[0076] Furthermore, while some embodiments / arrangements described herein include some but not other features included in other embodiments / arrangements, combinations of features of different embodiments / arrangements are meant to be within the scope of the invention, and form different embodiments / arrangements, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments / arrangements can be used in any combination.Specific Details

[0077] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.Terminology

[0078] In describing the preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplisha similar technical purpose. Terms such as “forward”, “rearward”, “radially”, “peripherally”, “upwardly”, “downwardly”, and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms.Different Instances of Objects

[0079] As used herein, unless otherwise specified the use of the ordinal adjectives “first”, “second”, “third”, etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.Scope of Invention

[0080] Thus, while there has been described what are believed to be the preferred arrangements of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention.

[0081] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.Industrial Applicability

[0082] It is apparent from the above, that the arrangements described are applicable to the configuration and manufacture of tamper resistant enclosures.

[0083] It will be appreciated that the tamper resistant enclosures and methods for their manufacture are described / illustrated above at least substantially provide a tamper resistant enclosure.

[0084] The tamper resistant enclosures and methods described herein, and / or shown in the drawings, are presented by way of example only and are not limiting as to the scope of the invention. Unless otherwise specifically stated, individual aspects and components of the tamper resistant enclosures and methods may be modified, or may have been substituted therefore known equivalents, or as yet unknown substitutes such as may be developed in the future, or such as may be found to be acceptable substitutes in the future. The tamper resistant enclosures and methods may also be modified for a variety of applications while remaining within the scope and spirit of the claimed invention, since the range of potential applications is great, and since it is intended that the present tamper resistant enclosures be adaptable to many such variations.Variations and Modifications

[0085] It will be realized that the foregoing has been given by way of illustrative example only and that all other modifications and variations as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth.

[0086] In this specification, adjectives such as first and second, left and right, top and bottom, and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Where the context permits, reference to an integer or a component or step (or the like) is not to be interpreted as being limited to only one of that integer, component, or step, but rather could be one or more of that integer, component, or step etc.

[0087] The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. The invention is intended to embrace all alternatives, modifications, and variations of the present invention that have been discussed herein, and other embodiments that fall within the scope of the above-described invention.

Claims

CLAIMS:1 . A tamper-resistant enclosure for protecting an electronic circuit, comprising: an outer casing formed of a rigid material; a plurality of nested aramid fibre enclosures disposed within the outer casing; at least one metal enclosure interspaced between the plurality of nested aramid fibre enclosures; and woven fibre sheet material enveloping the electronic circuit and filling a remaining internal volume of an inner-most enclosure.

2. The tamper-resistant enclosure of Claim 1 , wherein the plurality of fibre material enclosures comprises a high-strength synthetic fibre.

3. The tamper-resistant enclosure of Claim 2, wherein the high-strength synthetic fibre is an aramid fibre.

4. The tamper-resistant enclosure of Claim 2, wherein the high-strength synthetic fibre is a polyamide fibre.

5. The tamper-resistant enclosure of any one of the preceding claims, wherein the casing is formed of a rigid material selected from the group consisting of: metal; plastic; and a composite material.

6. The tamper-resistant enclosure of any one of the preceding claims, wherein the one or more metal enclosures are configured to provide electromagnetic shielding for the electronic circuit.

7. The tamper-resistant enclosure of any one of the preceding claims, wherein the fibre sheet material comprises a woven aramid fibre configured to resist cutting and tampering.

8. The tamper-resistant enclosure of any one of the preceding claims, wherein the plurality of fibre material enclosures are bonded to the one or more metal enclosures with an adhesive to prevent separation.

9. The tamper-resistant enclosure of any one of the preceding claims, wherein the fibre sheet material is configured to fill at least 90% of the remaining airspace within the inner-most enclosure to prevent insertion of tampering tools.

10. The tamper-resistant enclosure of any one of the preceding claims, wherein the plurality of fibre material enclosures comprises at least three nested fibre layers, each layer having a thickness of at least 0.5mm.

11. The tamper-resistant enclosure of any one of the preceding claims, wherein the one or more metal enclosures comprise a corrosion-resistant metal selected from the group consisting of: stainless steel; aluminium; copper; steel or stainless steel; nickel; nickel-iron alloy; tungsten; lead; depleted uranium; boron-steel; and titanium.

12. The tamper-resistant enclosure of any one of the preceding claims, wherein the fibre sheet material is treated with a chemical coating to enhance resistance to moisture and degradation.

13. The tamper-resistant enclosure of any one of the preceding claims, further comprising a tamper-detection mechanism integrated into at least one of the plurality of fibre material enclosures, the tamper-detection mechanism configured to detect a breach of the enclosure.

14. The tamper-resistant enclosure of Claim 13, wherein the tamper-detection mechanism comprises a conductive fibre mesh configured to trigger an alert upon disruption.

15. The tamper-resistant enclosure of Claim 13, wherein the tamper-detection mechanism comprises a fibre optic cable woven into at least one of the plurality of fibre material enclosures, the fibre optic cable configured to detect tampering by disruption of light transmission.

16. The tamper-resistant enclosure of any one of Claims 13 to 15, further comprising a destructive mechanism operatively coupled to the tamper-detection mechanism, the destructive mechanism configured to destroy at least a portion of the electronic circuit upon detection of a tampering attempt.

17. The tarn per- resista nt enclosure of Claim 16, wherein the destructive mechanism comprises a chemical agent release system configured to release a corrosive substance onto the electronic circuit upon activation by the tamper-detection mechanism.

18. The tarn per- resista nt enclosure of Claim 16, wherein the destructive mechanism comprises an electrical overload circuit configured to deliver a high-voltage pulse to the electronic circuit to render it inoperable upon detection of tampering.

19. The tamper- resista nt enclosure of Claim 16, wherein the destructive mechanism comprises an explosive device configured to detonate and destroy at least a portion of the electronic circuit upon activation by the tamper-detection mechanism.

20. The tamper-resistant enclosure of Claim 19, wherein the destructive mechanism is embedded within the fibre sheet material such that on detonation, the fibre sheet material is converted to a plurality of ballistic fragments for destruction of the electronic circuit.

21. A tamper-resistant enclosure for protecting an electronic circuit, comprising: an external casing formed of a rigid material; a plurality of nested aramid fibre enclosures disposed within the external casing; at least one metal enclosure interspaced between the plurality of nested aramid fibre enclosures; and woven fibre sheet material enveloping the electronic circuit and filling a remaining internal volume of an inner-most enclosure.

22. The tamper-resistant enclosure of Claim 21 , wherein the non-woven fibre sheet material comprises an aramid fibre configured to provide tamper evidence upon attempted penetration.

23. The tamper-resistant enclosure of Claim 21, further comprising a tamper-detection circuit embedded within at least one of the plurality of nested aramid fibre enclosures, the tamper-detection circuit configured to signal a breach attempt.

24. A method of protecting an electronic circuit within a tamper-resistant enclosure, comprising: providing a casing; nesting a plurality of fibre material enclosures within the casing and within each other; interspacing one or more metal enclosures between the plurality of fibre material enclosures; placing the electronic circuit within an inner-most enclosure; and covering the electronic circuit with a fibre sheet material that fills a remaining airspace within the inner-most enclosure.

25. The method of Claim 24, further comprising: integrating a tamper-detection mechanism into at least one of the plurality of fibre material enclosures; wherein the tamper-detection mechanism is configured to detect and signal an attempt to breach the tamper-resistant enclosure.

26. A tamper-resistant assembly for electronic circuitry, the assembly comprising: an external casing; a plurality of fibre material enclosures nested within the casing and within each other;one or more metal enclosures nested within the casing and interspaced with the one or more fibre material enclosures; a woven fibre material configured to cover components of the electronic circuit and fill a remaining airspace volume within an inner-most enclosure of the plurality of fibre material enclosures and the one or more metal enclosure.

27. A tamper-resistant assembly as claimed in Claim 26, wherein the woven fibre material is configured to fil at least 90% of the remaining airspace volume.

28. A tamper-resistant assembly as claimed in Claim 26, wherein an inner-most fibre material enclosure is configured to receive an electronic circuit board comprising a plurality of circuit elements.

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