CN110103475B

CN110103475B - Shell and manufacturing method thereof

Info

Publication number: CN110103475B
Application number: CN201910355779.1A
Authority: CN
Inventors: 胡之斐; 李振
Original assignee: Dinghyun Commercial Code Evaluation Technology Shenzhen Co ltd
Current assignee: Dinghyun Commercial Code Evaluation Technology Shenzhen Co ltd
Priority date: 2019-01-26
Filing date: 2019-04-29
Publication date: 2021-07-06
Anticipated expiration: 2039-04-29
Also published as: CN110103475A

Abstract

The invention provides a shell and a manufacturing method thereof, wherein the manufacturing method comprises the following steps of S1, establishing a three-dimensional digital model of the shell, wherein the shape of the shell is controlled by random numbers; and S3, printing the three-dimensional digital model by adopting a 3D printing device to form the shell. The manufacturing method adopts the random number to control the shape of the shell, so that the shape of the shell is random, and the electromagnetic waves emitted by the shell are random in direction and amplitude, thereby increasing the difficulty of separating the interfering electromagnetic waves and the required electromagnetic waves by an attacker and improving the safety.

Description

Shell and manufacturing method thereof

Technical Field

The invention relates to the technical field of information security, in particular to a shell and a manufacturing method thereof.

Background

Research at home and abroad shows that electromagnetic leakage signals of a computer can be captured through receiving equipment (a receiver, a frequency spectrograph and the like), and operation information of the computer is restored through a post-processing method. The problem of computer electromagnetic radiation leakage has attracted high attention from various countries, and in order to prevent the information from spreading in the air, special technical measures for preventing and inhibiting electromagnetic radiation leakage must be taken, and the technical measures include: jamming technology (jammers), shielding technology (shielded rooms), and Tempest technology (low-radiation machines). The interference device in the prior art has the defects of complex structure and higher cost, and the shell of the interference device is mostly made of a shell with a common shape, so that the interference enhancement effect is not achieved, and the strength of an interference signal is often reduced.

Disclosure of Invention

In order to solve the technical problem that an interference unit in the prior art is lack of a proper shell, the embodiment of the invention provides a shell and a manufacturing method thereof.

The manufacturing method of the shell provided by the embodiment of the invention comprises the following steps:

s1, establishing a three-dimensional digital model of the shell, wherein the shape of the shell is controlled by random numbers;

and S3, printing the three-dimensional digital model by adopting a 3D printing device to form the shell.

Further preferably:

the shape function of the shell is F (x, y, z), and the coefficients of x, y and z are random numbers;

alternatively, the shape function of the housing is F (x, y, z, n)₁,…,n_m) The coefficients of x, y, z are random numbers, n₁,…,n_mM is an integer greater than zero for the rule control parameter.

Further preferably:

wherein, U₁Set, …, U_tThe union of the sets is the extent of the shell, and t is an integer greater than zero.

Further preferably, the random number is generated by a pseudo random number generation unit; alternatively, the random number is generated by a true random number generating unit.

It is further preferred that any two housings are not identical.

Further preferably, if the housing formed in step S3 is a plastic housing, the method further includes step S4:

and S4, forming a metal layer on the surface of the plastic shell.

Further preferably, if the housing formed in step S3 is a metal housing, the method further includes step S5:

and S5, performing plastic injection molding on the inner surface or the outer surface or the inner and outer surfaces of the metal shell.

Further preferably, between steps S1 and S3, step S2 is further included:

and S2, converting the format of the three-dimensional digital model to generate a file which can be recognized by the 3D printing equipment.

The embodiment of the invention also provides a shell, wherein the shell is manufactured according to the manufacturing method.

The embodiment of the invention also provides a shell, which comprises a shell body, wherein the shell body is provided with a plurality of irregular conducting wires or a metal shell with an irregular protruding structure and/or a recessed structure;

the irregular conductive wire comprises a conductive wire with the cross section area changing in the length direction or a conductive wire with a convex or concave surface or a conductive wire with at least two bends or bends different from each other; the variation is random; alternatively, the shape or arrangement of the protrusions or depressions is random; or, the shape or arrangement of the bending or curving is random; alternatively, the shape or arrangement of the irregular protruding structures and/or depressed structures is random;

the shell is manufactured according to the manufacturing method.

The manufacturing method of the shell of the embodiment of the invention adopts the random number to control the shape of the shell, so that the shape of the shell is random, and the electromagnetic waves emitted by the shell are random in both direction and amplitude, thereby increasing the difficulty of separating the interfering electromagnetic waves and the required electromagnetic waves by an attacker and improving the safety.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

Fig. 1 is a flowchart of a method for manufacturing a housing according to an embodiment of the invention.

FIG. 2 is a schematic diagram of a conductive line according to an embodiment of the invention.

FIG. 3 is a second conductive line of the embodiment of the invention.

FIG. 4 is a schematic diagram of a conductive line III according to an embodiment of the invention.

FIG. 5 is a schematic diagram of a conductive net according to an embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a metal shell according to an embodiment of the invention.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the specific embodiments described herein are merely illustrative of the application and are not limiting of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terms "first", "second" and "third" in this application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any indication of the number of technical features indicated. It will thus be appreciated that features defined as "first", "second" and "third" may explicitly or implicitly include at least one such feature. For example, a first plane of type may be referred to as a second plane of type, and similarly, a second plane of type may be referred to as a first plane of type, without departing from the scope of the present application. The first plane-like surface and the second plane-like surface are both planar surfaces, but they are not the same plane-like surface. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specifically limited otherwise. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The core idea of the invention is to adopt random numbers to control the shape of the shell, so that the shape of the shell is random, and the electromagnetic waves emitted by the shell are random in direction and amplitude, thereby increasing the difficulty of separating the interfering electromagnetic waves and the required electromagnetic waves by an attacker and improving the safety.

Referring to fig. 1, a method for manufacturing a housing according to an embodiment of the present invention includes the following steps:

and S1, establishing a three-dimensional digital model of the shell, wherein the shape of the shell is controlled by random numbers.

The establishment of the three-dimensional digital model of the shell can be completed by drawing software or scanning entity input by scanning equipment. When designed by a drawing software, such as UG NX or Pro/engine, etc., the shape of the shell can be controlled by a random number, for example, by changing the parameters of a curved surface. By scanning the entity input, can replace the coordinate value of some points at random through the random number, change and scan the entity shape.

In general, the shape of the housing may be represented by a function F (x, y, z), which is a shape function. For complex shapes, the shape function F (x, y, z) should be very complex. By taking the random number as a coefficient of x, y, z, the shape of the housing can be controlled, so that the shape of the housing is unpredictable and difficult to obtain by reverse engineering. The shape function F (x, y, z) corresponds to the stereoscopic digital model. Of course, once the solid digital model is determined, the shell shape is determined.

The embodiment preferably establishes a shape function library, which contains various shape functions, such as a sphere shape function, a cube shape function, a pyramid shape function, and the like.

The shape function F (x, y, z) can be taken from a function of the shape function library, e.g., shape function F (x, y, z) = aX ^2+ bY ^2+ cZ ^2=0, and the a, b, c can be random numbers. The shape function F (x, y, z) may have several sets a, b, c, each set a, b, c having random values. The value ranges of X, Y, Z (referred to as X, Y, Z value ranges) corresponding to each group a, b, and c are also random, but the value ranges of X, Y, Z are not repeated or overlapped (except for the junction of the value ranges of X, Y, Z of every two groups), and the union of the value ranges of X, Y, Z corresponding to all groups a, b, and c (i.e., the union of the value ranges of X, Y, Z) is the range of the housing. That is, the range of the housing is a constraint condition of the value range of X, Y, Z corresponding to each group a, b, c.

The shape function F (x, y, z) may be a function obtained by performing an operation on a plurality of shape functions taken from the shape function library.

In order to increase the richness of the shape of the shell, the shape function of the shell may be a multi-dimensional function, preferably the shape function of the shell is F (x, y, z, n)₁,…,n_m) The coefficients of x, y, z are random numbers, n₁,…,n_mM is an integer greater than zero as a rule control parameter; m may take the value 1, in which case the shape function F (x, y, z, n)₁) Is a four-dimensional function. Further preference is given to the shape function F (x, y, z, n)₁,…,n_m) For piecewise functions, there are different functions for different sets, namely:

wherein, U₁Set, …, U_tThe union of the sets is the extent of the shell, and t is an integer greater than zero. t may take the value 1, in which case the shape function F (x, y, z, n)₁,…,n_m) Is a non-segmented function. One of the effects of the rule control parameters may be on eachThe piecewise function selects different function types, and of course, the rule control parameter can have other functions to control the shape of the shell and enrich the shape of the shell. In particular, the rule controls a parameter (n)₁,…,n_m) Deciding which function in the shape function library the f-function (i.e., each piecewise function) is; the rule controls the parameter (n)₁,…,n_m) Preferably random numbers, so that there are a wide variety of possibilities and variables for the choice of f-function.

The random number can be generated by a true random number generating unit, and the safety performance is high. The true random number generating unit may be a true random number generating circuit comprising: a high frequency oscillator for generating a high frequency clock signal; a low frequency oscillator for generating a noise source based on the resistance thermal noise; the clock input end CLK of the T trigger is connected with the output end of the low-frequency oscillator, and a noise source generated by the low-frequency oscillator is used as a clock signal; the input end of the multistage frequency divider is connected with the output end of the high-frequency oscillator, and the output end of the multistage frequency divider is connected with the T end of the data input end of the T trigger; the low-frequency oscillator samples a high-frequency clock signal subjected to frequency division by the multistage frequency divider, and a true random number is output from the Q end of the output end of the T trigger. The true random number generating circuit has good random characteristics and is simple to implement. Of course, the true random number generating unit may also be other true random number generating circuits, devices or components.

The random number can be generated by a pseudo-random number generation unit, the cost can be reduced while the safety is ensured, and the pseudo-random number generation unit is preferably adopted in the embodiment, so that the system random number function can be directly called in modeling. Or, the pseudo-random number generation unit comprises a feedback shift register which is formed by connecting a plurality of D triggers in series.

To increase the difficulty of attack by an attacker, it is preferable that any two shells are not identical, so that no two shells are identical in shape, which is easily achieved by adjusting the range of random numbers. After an attacker breaks one shell, the attacker cannot attack the next shell through simple copying, so that the time cost of the attacker is increased, and the safety performance is improved.

If the file type of the stereoscopic digital model is an STL file or an OBJ file or a STEP file or an IGES file, STEP S2 may be omitted.

S2, format conversion is performed on the stereoscopic digital model to generate a file recognizable by the 3D printing device, for example, a file such as an STL file, an OBJ file, a STEP file, or an IGES file.

The format conversion of the present embodiment generally includes exporting a format file and repairing the format file.

The application takes the STL file as an example, and other file types are processed similarly.

The STL files exported by software are often damaged and damaged seriously and cannot meet the requirements of direct printing. The reason is two cases: first, the model itself is made up of sheets, not a complete entity; secondly, probably because the programs in different software are different, data are easy to lose when format conversion is performed on the file (the model file has defects such as cracks, broken faces and the like), so the step generally needs to perform broken face repair on the STL model to meet the requirements of the 3D printer.

Specifically, the exported STL format file is imported into related repair software (for example, in Geomagic software), the repair software is used for repairing the model (namely, the model is repaired through the Geomagic software, the defects in the model are repaired one by one through the functions of filling a single hole, completely filling, reversing the normal and the like in the Geomagic, the smoothness degree of a triangular patch is repeatedly checked in the repair process, the repair of the whole model is finally completed), the STL file is exported after the repair is completed, and the STL file at the moment can be printed in a 3D printer.

There are various techniques used for the 3D printing apparatus, and those skilled in the art can select an appropriate 3D printing apparatus as desired. Several 3D printing techniques are briefly described below:

1. FDM technique (melt extrusion molding process): fused deposition rapid prototyping, the main materials ABS and PLA. The material for the melt extrusion molding (FDM) process is typically a thermoplastic material such as wax, ABS, PC, nylon, etc., fed in filament form. The material is heated and melted in the spray head. The nozzle moves along the cross-sectional profile and filling trajectory of the part while extruding the molten material, which solidifies rapidly and bonds with the surrounding material. Each layer is formed by stacking on the upper layer, and the upper layer plays a role in positioning and supporting the current layer.

2. SLA technique (photocuring molding): and (4) carrying out photocuring molding, wherein the main material is photosensitive resin. The principle of photocuring molding works based on the principle of photopolymerization of liquid photosensitive resins. The liquid material can be quickly photopolymerized under the irradiation of ultraviolet light with certain wavelength and intensity, the molecular weight is increased sharply, and the material is converted from the liquid state to the solid state.

3. 3DP technique (three-dimensional printing process): three-dimensional powder bonding, and main material powder materials such as ceramic powder, metal powder and plastic powder. The three-dimensional printing (3DP) process was developed by Emanual Sachs et al, the national institute of technology and technology. Sachs, 1989, filed a 3DP (Three-Dimensional Printing) patent, which is one of the core patents in the category of non-forming material droplet ejection forming.

4. SLS technique (selective laser sintering process): selective laser sintering, the main material powder material. The SLS process, also known as selective laser sintering, was developed in 1989 by schard, c.r. Dechard, austin division, university of texas, usa, and was formed using a powdered material. Spreading material powder on the upper surface of the formed part and leveling; scanning the section of the part on the newly paved new layer by using a high-intensity CO2 laser; sintering the material powder under the irradiation of high-intensity laser to obtain the section of the part, and bonding the section with the formed part below; after one layer of cross section is sintered, a new layer of material powder is laid, and the lower layer of cross section is selectively sintered.

5. LOM technique (layered entity fabrication): the method is divided into solid manufacturing and mainly comprises paper, metal films and plastic films. The LOM process is known as layered entity fabrication and was successfully developed in 1986 by Michael Feygin, Helisys, USA. The company has introduced two models of molding machines, LOM-1050 and LOM-2030.

The shell is printed and formed in the step S3, various required shapes can be achieved, the shapes can be controlled to be different, interference electromagnetic waves emitted by the shell have strong randomness, and an attacker is difficult to crack, so that the shell manufacturing method has a good application prospect.

If the desired housing, for example, a housing made of both metal and plastic or a housing made of only metal, is obtained by 3D printing, it can be directly used, and the manufacturing method of the embodiment of the present invention is completed.

If the housing obtained by 3D printing is a plastic housing, then it is necessary to perform step S4, which is S4: and forming a metal layer on the surface of the plastic shell. The metal layer has the function of generating interference electromagnetic waves, and the metal layer is attached to the plastic shell, so that the metal layer is random in shape, and the interference of the generated interference electromagnetic waves is very strong. The method for forming a metal layer in this step is very many, for example, the metal layer is placed in another 3D printer for printing, and can also be formed in a plating mode.

If the housing obtained by 3D printing is a metal housing, in order to adapt to some applications, step S5 is further performed, where step S5: and carrying out plastic injection molding on the inner surface or the outer surface or the inner and outer surfaces of the metal shell. The metal shell comprises a hollow structure, such as a metal net, and also comprises a non-hollow structure, namely a common metal shell. The plastic injection molding on the inner surface or the outer surface or the inner and outer surfaces of the metal shell can be applied to more scenes, particularly occasions with high requirements on electric contact or insulation.

The embodiment of the invention also provides a shell manufactured by the method, and the shell can be applied to the packaging of various electronic devices, the shells of various electronic equipment or the outer layers of buildings. The housing of the embodiment of the present invention or the inner housing or the outer housing having the housing (i.e., the housing is a part of the outer housing or the inner housing) may be applied to various fields where it is necessary to generate interfering electromagnetic waves.

The embodiment of the invention also provides a shell, which comprises a shell body and a plurality of irregular conductive wires or a metal shell with an irregular protruding structure and/or a recessed structure, wherein the plurality of irregular conductive wires or the metal shell is arranged on the shell body. The irregular conductive wire comprises a conductive wire with the cross section area changing in the length direction or a conductive wire with a convex or concave surface or a conductive wire with at least two bends or bends different from each other; the variation is random; alternatively, the shape or arrangement of the protrusions or depressions is random; or, the shape or arrangement of the bending or curving is random; alternatively, the shape or arrangement of the irregular prominence and/or depression structures is random. The shell body can be a plastic shell and mainly plays a role in supporting or protecting. The shell is manufactured and formed by the method.

FIG. 2 is a schematic diagram of a conductive line according to an embodiment of the invention. FIG. 3 is a second conductive line of the embodiment of the invention. FIG. 4 is a schematic diagram of a conductive line III according to an embodiment of the invention. FIG. 5 is a schematic diagram of a conductive net according to an embodiment of the present invention. Fig. 6 is a schematic structural diagram of a metal shell according to an embodiment of the invention.

Referring to fig. 2 to 6, the irregular conductive lines 131 in the present embodiment preferably include conductive lines with a cross-sectional area varying along the length direction, as shown in fig. 4, the cross-sectional area is from large to small and then from small to large; alternatively, the irregular conductive line 131 is a conductive line having a protrusion or a recess on the surface, and as shown in fig. 4, the conductive line 131 includes several recesses, such as an upper recess 1315 and a lower recess 1316; alternatively, the irregular conductive line 131 is a conductive line with at least two bends or bends that are different or a conductive line with at least two bends or bends that are not in a plane, as shown in fig. 2 and 3, and the bends or bends in fig. 2 are in the same plane, for example, the bend 1311 is different from the bend 1312; in fig. 3, at least one of the bends or curves is not in the same plane, and bend 1313 is not in the same plane as bend 1314. The irregular conductive wires may also form an irregular conductive wire mesh, which may be irregular in shape or have different mesh shapes, or the conductive wires constituting the conductive wire mesh may be irregular, as shown in fig. 5, and the irregular conductive wire mesh 132 includes irregular conductive wires and irregular-shaped meshes, for example, the mesh 1323 is different from the mesh 1324, and the mesh 1324 is irregular and has an input terminal 1321 and an output terminal 1322. To further increase unpredictability and increase attack difficulty, embodiments of the present invention prefer that the variation in the cross-sectional area in the length direction is random; the shape or arrangement of the projections or depressions is random; the shape or arrangement of the bends or curves is random. Random means that there is no requirement for variation, shape or arrangement, and is not limited as long as it can be achieved. The conductive wires and the conductive wire mesh can be made of metal, semiconductor or other conductive materials.

Referring to fig. 6, the metal shell 133 according to the embodiment of the present invention has a plurality of protruding structures 1331 and/or recessed structures 1332, the protruding structures 1331 and the recessed structures 1332 are irregular, and preferably, the shapes or the arrangement of the protruding structures 1331 or the recessed structures 1332 are random. The protruding structure and the recessed structure of the metal sheet are the same as those of the metal shell 133, and are not described in detail.

Although the embodiments have been described with reference to the accompanying drawings, it is to be understood that various changes and modifications may be effected therein by one of ordinary skill in the art in light of the above teachings. For example, the described techniques may be performed in an order different from that described, and/or the components of the described systems, structures, devices, circuits, etc. may be combined or combined in a manner different from that described, and may be replaced or substituted with other components or equivalents to achieve suitable results. Therefore, other configurations, other embodiments, and equivalents to the claims are intended to fall within the claims.

Claims

1. A method for manufacturing an interference device shell is characterized by comprising the following steps:

s1, establishing a three-dimensional digital model of the interference device shell, wherein the shape of the interference device shell is controlled by random numbers; further comprising:

establishing a shape function library;

the shape function of the housing of the interference device is

Wherein, the coefficients of x, y and z are random numbers, n₁，...，n_mThe rule control parameters are used for determining which shape function in the shape function library each piecewise function is, and m is an integer greater than zero; u shape₁Aggregate,.. U_tThe union of the sets is the range of the housing of the jammer, and t is an integer greater than zero;

and S3, printing the three-dimensional digital model by adopting a 3D printing device to form the interference device shell.

2. The method of making a disrupter housing as claimed in claim 1, characterized in that the random number is generated by a pseudo-random number generator unit; alternatively, the random number is generated by a true random number generating unit.

3. The method of making a disrupter housing as claimed in claim 1, characterized in that any two disrupter housings are different.

4. The method for manufacturing a disturber housing according to claim 1, wherein if the disturber housing formed in step S3 is a plastic disturber housing, further comprising step S4:

and S4, forming a metal layer on the surface of the plastic interference housing.

5. The method for manufacturing the jammer housing of claim 1, wherein if the jammer housing formed in step S3 is a metal jammer housing, the method further comprises step S5:

and S5, performing plastic injection molding on the inner surface or the outer surface or the inner and outer surfaces of the metal interference housing.

6. The method for manufacturing a jammer housing of claim 1 further comprising, between steps S1 and S3, step S2:

7. An interference housing made according to the method of manufacture of any one of claims 1 to 6.

8. The shell of the interference unit comprises a shell body and is characterized in that a plurality of irregular conducting wires are arranged on the shell body;

the irregular conductive lines comprise conductive lines with cross-sectional areas that vary in the length direction, the variations being random;

or, the irregular conductive wire comprises a conductive wire with protrusions or depressions on the surface, and the shapes or the arrangement of the protrusions or depressions are random;

or, the irregular conductive wire comprises at least two conductive wires with different bending or at least two conductive wires with different bending or bending not in one plane, and the shapes or the arrangement of the bending or bending are random;

the jammer housing is made according to the method of manufacture of any one of claims 1 to 6.

9. The shell of the interference device comprises a shell body and is characterized in that a metal shell with an irregular protruding structure and/or a concave structure is arranged on the shell body;

the shape or arrangement of the irregular protruding structures and/or the concave structures is random;