Method and device for high-security encyphered marking to protect high-value objects.

The invention relates to the marking of valuables, especially works of art or documents, for their protection against theft, resale or counterfeiting.

It relates more particularly to a method and an encrypted marking device, required to enable the marking of valuables and allow subsequently and if necessary, identify or authenticate said objects, and this irrefutably .

By "crypto-marking" means now appoint a hidden and invisible marking in a hidden location of the object, known only to its owner and undetectable by third parties.

The invention is particularly applicable to the identification of artworks such as paintings, sculptures, ceramics, pottery, vases, furniture, vintage clothing, carpets, tapestries, old books, engravings, lithographs, objects collection, etc.

It also applies to the identification of capital goods such as motor vehicles, stereo systems, computers, televisions, radios, video recorders, cameras, cameras, etc.

The invention also applies to protection against counterfeiting of all kinds of documents and official documents, including bank documents, checks, contracts, wills, paper money, identity papers, legal papers, etc.

There are currently very few means to protect valuable items such as artwork or other movable property against theft, resale or counterfeiting. In addition, for an owner, it is very difficult to provide conclusive evidence that the stolen, resold or counterfeited, when found, he had.

Another difficulty is that all the works of art are not inventoried. If so, paintings by masters such, it is not the same for the particular furniture.

In France, in legal terms, Article 2279 of the Civil Code provides:

"Actually furniture, possession is nine. However," the one who has lost or to whom it was stolen a thing or "an object, can claim for three years" from the date of loss or theft, against in the hands "which he finds, unless it's appeal against" the one which he holds. "

Under these conditions, it is absolutely necessary, in case of loss or theft, can provide proof of ownership of his property when it was left in the hands of a third party.

Among the currently existing means to protect valuables, including artworks, essentially discloses the use of metal implants that the owner of the object inserted in a particular location of the object, known only to him -even.

Thus, in case of loss or theft, whether the object is found in the hands of a third party, the owner can demonstrate theoretical ment of this property by going in making remove the implant or an x-ray of object in the region containing the implant.

Unfortunately, such a process is not completely reliable because the implant can be identified by third parties and that the use of X-rays or gamma rays.

have also been proposed to apply, on an object to be protected, a chemical compound selected, or target compound, capable of being subsequently detected by any appropriate means, especially by another chemical compound, or probe compound.

Thus the European Patent Application No. 0,090,130 provides a method of authenticating a document by means of a color reaction system using a color former and a developer substance. One of the two substances is applied to the object, while the other substance is used for detection purposes. When both substances are contacted, there occurs a characteristic color reaction that is used to authenticate the document.

Such a process, too, unreliable given the limited number of color reaction systems could be used.

It is therefore an object of the invention to provide a method capable of irrefutable proof of ownership of an object of value, including a work of art.

It is also an object of the invention to provide an encrypted marking method capable of ensuring the identification of the object of value, marking itself can be issued and carried out by an expert and that, in using the method of the invention.

The invention also aims to provide a clean process to identify official papers or documents, such as contracts, deeds, wills, official papers, paper money, checks, stocks, etc.

Another object of the invention is to provide such a crypto-marking method wherein the marking of the object of value can not be detected by third parties, including methods of detecting X-rays or gamma rays.

Finally, another object of the invention is to provide an encrypted marking device suitable for the implementation of the inventive method.

The invention proposes to produce the encrypted marking valuables, and that using some of the dramatic progress that biology has made in recent years and now make available molecular tools of great efficiency. Of these, nucleic probe technology is certainly the most attractive and the most powerful tool.

The technology of nucleic acid probes based on the high affinity between two strands of complementary nucleic acid. This affinity is perfectly illustrated by theoretical estimates of the dissociation constant (Kd) of a hybrid, also called "duplex", 273 base pairs.

This value is of the order of 10⁻²³ M to 5 ° C below the temperature of semi-denaturation of the duplex (Tm). For comparison, the antigen-antibody reactions have a Kd of between 10⁻⁵ and 10⁻⁹ M.

According to this technology, it is possible to construct nucleic probes (nucleic acid probes) of sequences complementary to target nucleic acids and realize the in vitro formation of duplexes.

If the probe is labeled, either radioactively or non-radioactively, it is then possible to detect the duplex so formed.

The use of nucleic probes and can detect living organisms (the latter are normally all holders of nucleic acids representing their genetic heritage), if we know the sequence or a portion of the nucleic acid sequence of such organizations.

Labeled probe in advance and capable of hybridizing to the target nucleic acid contained by the organism, leads to the production of a hybrid or duplex, which allows the marking detection.

It is possible to detect many viruses, bacteria, parasites, fungi, etc. in biological media.

Nucleic probes also enable genetic study of more complex organisms, such as plants, animals and humans.

These studies such as the study and prevention of genetic diseases, the identification of the father or the mother in paternity testing, identification of a rapist or a criminal amongst suspects, etc.

Thus far, the nucleic acid probes have been used only for medical applications, food or scientists, for which the nucleic acids and in particular nucleic acid probes represent a tool of choice.

We have found, surprisingly, that the technology of nucleic probes could be used with success in protecting valuables, including works of art, to bring, and this in an absolutely irrefutable, evidence property stolen goods resold or counterfeited, provided that these have previously been marked by the process of the invention.

The invention relates, more particularly, an encrypted marking process high security for the valuables protector wherein there is applied to an object to be marked a target chemical compound own to be subsequently detected by a suitable detecting means.

According to an essential characteristic of the invention, this method comprises the steps of:<ul><li>a) preparing a solution of a selected target nucleic acid sequence of forming a marking pattern and possessing a chosen degree of fluidity,</li><li>b) incorporate a selected amount of said solution in each object of a class of objects to mark, thereby later time, if necessary, an operation</li><li>c) identification or authentication of the object by using a means for detecting said nucleic acid to reveal the marking.</li></ul>

Thus, the invention consists in the use of nucleic acid fragments (referred to as target nucleic acids) individuals by their sequence, size and nature and capable of being used as a target in detection of valuables, such as works of art, capital goods, official documents or contract, etc. A target nucleic acid can indeed be easily hidden to be detected directly or by subsequent hybridization and demonstrate, by this detection, ownership or authenticity of a valuable object.

Also note that the use of nucleic acids is particularly advantageous because they have exceptional strength and durability.

It may be noted, in fact, a nucleic acid, especially DNA, is a particularly resistant molecule, especially in dry conditions. An example illustrates this strength and even longevity of DNA. This is DNA from Egyptian mummies, which was cloned by genetic engineering, amplified and finally sequenced to enable the study of some of the mummies genes of more than 5000 years.

According to the invention, the target nucleic acid may be readily incorporated to the protected object. Thus, it can be hidden in a piece of art, furniture, a car, a good whatsoever, or incorporated into a paper, a contract, an official document.

In a preferred embodiment of the invention, step b) consists in applying the nucleic acid solution on a surface of a support to impregnate said solution and then incorporating the so impregnated support in each object to mark.

As carrier material, one can use, for example, nitrocellulose, polyamide (nylon) positively or uncharged loaded, paper, cardboard, wood, plastic, fabric, metal, glass, of ceramic, terracotta, an organic material in the form of beads or gel or else an inorganic material.

Especially preferred is use on a small-scale membrane may be inserted either in a thin flat object is still in the wound state in a thicker object.

Advantageously, the target nucleic acid is applied to a nitrocellulose support or nylon, positively charged or not, and having small dimensions. For example, it may be a membrane of 5 mm wide 15 mm long. This support, once impregnated with the target nucleic acid, can be rolled or folded, glued or incorporated into the piece to mark.

Alternatively, step b) may consist in applying the target nucleic acid solution directly to a surface of the object to be marked and that, in the case where the constituent material of said surface allows a direct attachment of said nucleic acid .

In step b) is advantageously applied to the nucleic acid solution as a marking by writing a number, a letter, a word, a phrase, a signature or any other sign marking.

In a preferred form of the invention, in step c), is used as detecting means, a simple nucleic acid probe sequence complementary to that strand of the target nucleic acid incorporated in the object and capable of hybridizing thereto, which allows a specific detection of the target nucleic acid by molecular hybridization.

The target nucleic acid and the probe nucleic acid may have different lengths, different sequences and be of different natures. It may be DNA or of natural or synthetic RNA, or synthetic compounds containing all or part of rare bases or modified bases.

It can also be used as target nucleic acid sequence, a sequence of the genome or the entire genome of a human person, for example the owner of the object to be marked. In this way we can then, by nucleic hybridization identify the owner as is done in paternity testing (DNA fingerprint) by probes called satellites or repeated or any other type of sensor capable of generating polymorphism identifying the owner 'irrevocably.

More generally, can be used in the invention, any target nucleic acid that can generate a polymorphism such that it can be detected by satellite probes, repeated sensors, etc. and any probe capable of detecting a polymorphism.

In a preferred embodiment of the invention, the target nucleic acid and the probe nucleic acid are complementary oligonucleotides whose sequences are obtained randomly, for example by means of a computer program.

Thus, the target nucleic acid is an oligonucleotide whose synthesis is achieved chemically. The sequence of the target nucleic acid is perfectly random and can be generated using a computer program, or using any other means.

If we take for example an oligonucleotide of 50 nucleotides in length, the probability of finding another time this sequence in nature or make random synthesis in the laboratory again is 1 chance in 1.26 10³⁰, is a highly unlikely event. It may be recalled here, for example, the whole human haploid genome size of 3x10⁹ base pairs, approximately.

In this preferred form of the invention, the complementary sequence, that is to say that of the probe nucleic acid, and is also used synthetic probe.

If the probe nucleic acid finds a target nucleic acid of complementary sequence, there occurs a hybridization to form a hybrid or duplex.

This hybrid can be detected by any suitable detection means, known in the field of nucleic acid probes.

Thus, detection of the hybrid formed can be effected after marking or not the probe.

The labeling of the probe can be accomplished radioactively or non-radioactively by any appropriate labeling system known in the field of nucleic acid probes. For this, one can, for example, using labeling methods described in the following publications: - Langer, PR Waldrop, AA and Ward, DC (1981) Proc. Natl. Acad. Sci. USA 78. 6633-6637. - Leary, JI, Brigati, DJ and Ward, DC (1983) Proc. Natl. Acad.SCI. USA 80, 4045-4049. - Chen, P., Fuchs, RPP, Sage, E., and Leng, M. (1984) Proc. Natl. Acad. Sci. USA 81, 3466-3470. - Kenz, M. (1983) EMBO J. 2, 817-822. - Kenz, and Mr. Kurz, C. (1984) Nucleic Acids Res. 12, 3435-3444. - Jablonski, E, Moomaw, EW, Tullis, R.II. and Ruth, JL (1986) Nucleic Acids Res. 14, 6115-6128. - Traincard, F., Ternyck, T., Dauchin, A. and Avrameas, S. (1983) Ann Immunol. (Inst. Pasteur) 134 D. 399-405.

In the case where the probe is not labeled, the detection of the hybrid can be made of specific or non-specific manner, with antibodies detecting single nucleic acids or double-stranded, proteins, or compounds having an affinity for nucleic acids.

For example, it may appeal to the detection, anti-hybrid antibody. This is linked antibodies detection enzyme which are incapable of binding to single-stranded nucleic acid but which, however, bind to a double stranded nucleic acid, as is the case of a hybrid .

Therefore, if formation of a hybrid, the anti-hybrid antibody binds to this hybrid and there is then revealed by the sensing enzyme.

To carry out the detection of the hybrid, we can appeal not only to chemical means, but also to physical means, for example electrical, electronic, magnetic or radio.

Use may in particular a piezoelectric detection system which emits a particular signal when there is hybridization. This signal can be detected and amplified by any suitable electronic system.

In a preferred embodiment of the invention, the probe is labeled with a nonradioactive labeling method. Advantageously, the marking and revelation are non-radioactive and use the markings to biotin, by sulfonation or the marking process described in French Patent Application n^o 88 09598 and the Application for Certification n Addition^o 89 03192 filed by the Applicant.

The target nucleic acid is preferably spread on the support, or directly on the object if possible, using a suitable applicator means.

As applicator means we can use a pen (fountain pen, ballpoint pen, felt pen), a tool for tracing the drawing, a brush, or an automated machine as an inkjet machine.

In a preferred embodiment of the invention, this application is done with the aid of a pen in which the cartridge was placed a solution of the probe nucleic acid in a suitable buffer for a good fluidity and a good conservation of the nucleic acid. The concentration is calculated so that it is easy to reveal subsequently the target nucleic acid and is easy to write with the pen.

For example, this concentration is such that the applicator means deposits from 10 pg to 10 ng of target nucleic acid per mm². Preferably, an amount of 1 ng / mm² seems advantageous.

For example, one can use the following buffer: 50 mM Tris pH: 8 20 mM EDTA Tween 20 0.3% 25 mM NaCl sodium azide 0.04% (or other preservative).

In a preferred form of the invention, a 5-digit number is written to the nucleic acid solution and with the pen on the support or, where appropriate, directly on the object itself. After drying, the issue is completely invisible and can not be revealed with the aid of the sequence complementary nucleic acid probe to that of the target nucleic acid that is only known by the owner of the object.

To ensure the disclosure, the hybridization conditions are important, in particular with the oligonucleotides. In fact, hybridization kinetics are dependent on the sodium ion concentration of the medium, the nature of the medium and the hybridization temperature. This temperature is itself dependent on the stability of the hybrids to be formed. This stability is finally connected directly to the content base guanine and cytosine (GC) of the nucleic acid.

From the random nucleotide sequence obtained for constituting the target nucleic acid, one can calculate the percentage of guanine and cytosine base of the oligonucleotide and thus define the optimal hybridization conditions.

It is these conditions alone that will be used for the revelation.

In another variant of the invention, one can use non-specific means of detecting the target nucleic acid. This means that such means are capable of recognizing, nonspecifically, a target nucleic acid sequence.

Of course, to provide incontrovertible proof of ownership of a marked object, according to the method of the invention, it is particularly desirable to use specific detection means, as described above.

In another aspect, the invention relates to a marking device encrypted high security for the protection of valuables, having a clean target chemical compound to be subsequently detected by a suitable detecting means.

According to an essential characteristic of the invention, this device comprises: - A solution of a target nucleic acid of chosen sequence forming a marking pattern and having a degree of fluidity selected, - A clean applicator means to extend said solution on a surface to be marked, and - A nucleic acid detecting means.

Advantageously, said solution further contains a clean buffer to maintain the target nucleic acid and to confer to this solution, the sufficient degree of fluidity to allow its use in the applicator means.

The applicator means may be, for example, a pen, a paintbrush, a drawing instrument or an automated machine, as already indicated above.

Advantageously, the device of the invention further comprises a support forming a surface to be marked for the solution and capable of being incorporated into the object to be marked.

This support is formed from a material selected from those listed above.

The support may be incorporated into a sheet of a document, for example window or bottom of the page, by stamping and / or by bonding by means of a hologram strip of security.

Can be achieved and various types of documents, particularly the specific contract to receive pages on one or more appropriately positioned supports the signatures of the contracting parties. If one tries to falsify the document replacing a carrier with another, the hologram strip deforms and we see immediately that there was fraud. The hologram strip is advantageously a thin aluminum strip that has undergone appropriate treatment holography.

In the description which follows, given solely by way of example, reference is made to the accompanying drawing, in which:<ul><li>- Figure 1 shows a clean surface to be marked according to the method of the invention, by means of an applicator pen; </li><li>- Figure 2 shows the same support roll form;</li><li>- Figure 3 shows the thus wound carrier before introduction into a suitable housing formed in the object to be protected;</li><li>- Figure 4 shows a document incorporating a support according to the invention;</li><li>- Figure 5 shows a document incorporating two supports according to the invention;</li><li>- Figure 6 is an enlarged sectional view enlarged along the line VI-VI of Figure 5; and</li><li>- Figure 7 shows a document incorporating two supports according to the invention in another embodiment.</li></ul>

It is firstly made to Figure 1 which shows a support 10 according to the invention consists, in the example, for a rectangular membrane 5 of 15 mm, representing about 75 mm² surface. This support is advantageously constituted by a polyamide membrane (nylon) or nitrocellulose.

One can, for example, using membranes such as those sold under the ZETA-PROBE brand or under the brand ZETA-BIND by CUNO company (Great Britain). One can also use nylon membranes such as those sold under the trademarks Gene-Screen NORMAL or Gene-Screen Plus by the company Dupont de Nemours (USA).

One can also use a nylon membrane such as that marketed under the trademark HY-BOND by the firm Amersham (UK).

One can also use a nitrocellulose membrane Schleicher and Schuell firm (Germany).

On the membrane 10 of Figure 1, is applied by means of a pen 11, a target nucleic acid solution prepared as indicated above. In the example, we write on this membrane a five-digit number known only to the owner of the object. After drying the solution, the number and applied on the support is completely invisible.

Then, in the example considered, the membrane 10 is wound to form a roll 12, as shown in Figure 2, which occupies an extremely reduced volume since the surface of the flat support is about 75 mm² and that the membrane thickness is a few tenths of mm. Once the membrane thus rolled, the volume occupied by the roller 12 is of the order of a few mm³. The roller 12 thus formed can be hidden in the protected object and this in a place known only by the owner.

As shown in Figure 3, can be drilled, using a mini-drill a hole 14 in a region of the object 16 to be protected and then insert the roller 12 in the hole thus formed. Then simply plug the hole with a suitable coating or sealant, leaving no visible trace of the hole previously done.

Referring now to Figure 4 which shows a document 18, for example a letter paper sheet, of generally rectangular shape which has, in lower part, a window 20 of rectangular shape. In the window 20, is inserted a membrane 22 of nitrocellulose or nylon, positively charged or not. We can thus, on the membrane 22, writing, sign or any sort of recognition of signs. Again, these signs, letters, words, phrases, signatures are completely invisible after drying.

Referring now to Figure 5 which shows a document 24, for example a letter paper sheet or a sheet contract, comprising footer two membranes 26 and 28 nitrocellulose or nylon forming a support according to the invention. These two membranes are squares of a few millimeters square and are arranged in the lower corners of the document that have been cut for this purpose. Each of the membranes is affixed to the document by a hologram strip 30, 32 as shown more particularly in Figure 6. Each of the bands holograms is advantageously an aluminum sheet of small thickness which has been treated by holography and which is stamped and / or glued for fixing of the membrane. Each band includes two parts respectively applied to the front and back of the document.

In the embodiment of Figure 7, the document 34 is provided at the bottom of page two membranes 36, 38 of rectangular shape which, between them, extend over the entire width of the document. The two membranes are connected to the document 34 by a hologram strip 40 which extends over the entire width of the paper and are interconnected by a hologram strip 42 which may have a length of several centimeters.

The membranes 26, 28, 36 and 38 can be used to receive co-contractors of the signatures.

The target nucleic acid and applied to the membrane 10 of Figure 1, on the membrane 22 of Figure 4, the membranes 26 and 28 of Figure 5 or on the membranes 36 and 38 of Figure 7 can not be revealed that using the appropriate complementary probe to identify or authenticate either the object 16 of Figure 3, or documents 18, 24 and 34 of figures 4, 5 and 7. This document is an act, a contract, paper money, check, an action, a will, etc.

The invention thus provides a triple safety to the owner of the object to be marked by the process according to the invention.

First, the support (nylon membrane for example) can be hidden in a place known only by the owner. The cache is not detectable by X-rays since the membrane and the nucleic acid are, one as the other, perfectly transparent to X-rays or gamma rays. Furthermore, the volume occupied by the membrane is extremely reduced since, with the rolled state, it is of the order of a few mm³.

Second, only the owner of the object knows the number written on the medium.

Third, the hybrid revelation can only be done with the nucleic acid probe of complementary sequence, known only by the owner, and this in hybridization conditions defined by the concentration bases guanine and cytosine of hybrid. However, this content is determined from the target nucleic acid sequence known only to the owner of the protected object.

Revelation may be made in the presence of a bailiff or of a sworn representative guaranteeing the normal operation of the detection operation and the use of specific complementary probe held by the owner of the protected object.

In the event that the protected object is a paper or a document, it is easy to include support for fragments, eg, nylon membranes, and to write any code number, signature or sign of recognition for to identify the document.

The paper used for making the document can be ordinary paper or special paper, eg a fluorescent security paper.

effect of such papers are known which comprise fluorescent patterns so that when it is irradiated by an ultraviolet light, they emit radiation of different colors.