RU2088971C1 - Measures for protecting securities against forgery - Google Patents

Abstract

FIELD: banks and miscellaneous offices dealing with securities and important documents. SUBSTANCE: measures include covering banknotes with protective code by scanning banknote material microstructure, determining vector of this banknote identifier, its encoding with digital electronic signature, encoding, and printing on denomination. EFFECT: improved effectiveness of forgery protection. 4 cl, 10 dwg

Description

 The invention relates to the field of protection of securities from counterfeiting and monitoring the status of securities and documents and can be used in banks and other institutions engaged in working with securities and documents.

Known methods for the protection of securities by applying on their surface in predetermined areas of magnetic marks, for example, by drawing a magnetic ink pattern [1]
The cost of such protection is determined by the complexity and degree of confidentiality used for labeling the process.

 A disadvantage of the known methods of protection is that in modern conditions illegal issuers (counterfeiters, manufacturers of counterfeit securities and documents) may have a modern technological base, and it will be difficult to distinguish a fake from the original.

Known methods of protecting securities by changing the structure of the material in different areas in a predetermined ratio, for example, by light absorption or reflection by visible rays and infrared rays [2]
The disadvantage of this method is that in the circulation of securities they become contaminated, in addition, destruction processes in the paper material occur over time. The above leads to a change in the optical properties of the paper material and during control it can be difficult to distinguish a fake from a script.

The closest technical solution (prototype) is a method of protection against counterfeiting securities, including applying a security code to them by entering the number of point parts and the corresponding coordinates and establish the authenticity and type of paper [3]
Counterfeit protection is effective if the cost of making a fake becomes commensurate with the price of the counterfeit security. As a result of the legal issuer applying each new level of protection, the cost of manufacturing securities increases significantly, and this protection is effective in a very short time, after which a significant number of fakes appear again.

 For example, applying magnetic marks of medium complexity costs up to $ 3, the introduction of a metal thread into paper costs $ 4, the use of special paints that reflect ultraviolet rays at a certain angle increases the cost of manufacturing a security by $ 8-10. The introduction of complex special magnetic marks and patterns with metal thread, the use of special paints with specified special characteristics of reflection and absorption of electromagnetic waves with especially high requirements for protection can bring the cost of manufacturing a security up to several hundred dollars.

 The rapid development of portable high-quality and relatively inexpensive printing equipment will lead in the near future to a complete loss of confidence in securities. Already now in money circulation, clients openly avoid using large bills, while other securities are repeatedly re-checked. This trend can lead to the collapse of the monetary system and the collapse of the economy.

 The disadvantage of this method is manifested in a slight difference between the cost of applying protection and its fake. In addition, the known coding system in the method has low survivability in time.

 The goal is to increase the effectiveness of security protection against counterfeiting and reduce its cost.

 The goal is achieved in that in the method of protecting banknotes and securities from counterfeiting, including applying a security code to them, according to the invention, the security code is applied by scanning the microstructure of the security material, determining the value of the identifier of the security paper, encrypting it with a digital signature, encoding it it is applied, for example, by typographic printing on a security according to a given law.

 The goal is also achieved by the fact that scanning the microstructure of the security to be secured is performed volumetricly in at least two intersecting planes.

The goal can also be achieved by the fact that scanning the microstructure of a security is carried out mainly in the visible region of the spectrum by optoelectronic conversion. Depending on the technological base available to the imitator of banknotes and securities, scanning can be carried out using a laser beam, microwave or ultrasonic radiation and other sensors [4]
The goal is also achieved by the fact that to reduce the effect on the security code of minor mechanical damage to the paper structure as a result of reversibility before applying the security code, it is mathematically converted into another code by noise-resistant coding [5]
A comparative analysis of known technologies and the claimed method shows that the claimed method differs significantly from each of the known, and from their combination, and therefore it can be characterized as having an inventive step.

 The proposed patent completely eliminates the main disadvantage of the known methods of protecting banknotes from counterfeiting, a slight difference between the cost of applying the protection and its counterfeiting.

 The essence of the method is as follows.

 Each security has its own individual characteristics. Some of these individual characteristics are the result of random factors in its manufacture and, in principle, cannot be exactly reproduced in the manufacture of another bill even on the same equipment. You can choose such random individual features that they cannot be artificially reproduced even when using fantastically modern technologies. For example, a microscopic relief of the surface of the paper or an individual micrograph of paper fibers in all the variety of their interweaving is undoubtedly such a set of individual features of a certain section in a particular piece of paper that cannot be exactly repeated at reasonable costs for this procedure.

 Using these individual characteristics, the legal issuer must choose some one-sided mathematical transformation and, conducting it over a variety of signs, obtain a protective sequence of characters that must be applied in a certain place of the security.

 In order to be able to verify the authenticity of securities, the issuer must openly publish a list of individual features used to protect, type of one-way security conversion, security verification key, code and place for applying security symbols.

The security user verifies its authenticity as follows:
a) reads the security sequence with the price of the paper;
b) using the key published by the issuer and one-way conversion, calculates the expected individual characteristics;
c) compares among themselves the calculated and measured individual characteristics in the checked security;
d) if individual characteristics coincide, the authenticity test is considered completed. If the signs do not match, the security is considered fake.

Counterfeiters for counterfeiting a security protected by the method described above have the following features:
a) follow the path that is familiar to them, i.e. choose a genuine security as a sample, fabricate a fake and apply a protective sequence on it that matches the sample. In this case, he will have to repeat exactly the same set of individual characteristics as the sample. If the issuer selects the individual characteristics correctly, such a fake is impossible.

b) try to “reverse” the one-way transformation published by the legal issuer. If successful, the counterfeiter will receive a reverse security key and will be able to independently generate protective sequences. In this case, he will get the opportunity to manufacture a "genuine" security. However, a legitimate issuer can always choose a one-way conversion of such high complexity that the task of its “reversibility” becomes unsolvable [7]
Thus, if the legitimate issuer makes the right choice of a set of individual attributes and a complex one-sided conversion, counterfeiting of securities becomes practically impossible.

 Consider a specific example of paper bill security.

где C индивидуальные признаки (идентификатор) купюры,
M защитная последовательность,
e открытый ключ расшифрования,
N составной модуль.The security code is applied by electronically scanning the microstructure of the protected paper note, for which, by means of optoelectronic conversion, the image of the paper base microstructure (the relative position of the fibers in the paper base of the note) is recorded on an area of 1 mm ² in a strictly defined place, for example, above a special tags (Fig. 1.)
A typical microstructure of the paper backing is shown in FIG. 2. The raster reading of this image with a resolution of 10 dots per 1 mm gives the following binary number 0000110011 (dark places 1, light 0), or in decimal form 307. Let RSA cryptosystem as the one-sided conversion be selected in the form [7]

where C is the individual characteristics (identifier) of the bill,
M is a protective sequence,
e public decryption key,
N compound module.

 In this example, we choose N P • Q 17 • 31 527, e = 7.

то есть d ключ шифрования, известный только законному эмитенту ценной бумаги.Then, through the Euler function, we calculate d such that

that is, d is the encryption key known only to the legal issuer of the security.

Так как Co 0100110011 307, то

M 307•205•307•205•443•307mod527 443•392•443•307•mod527 69.

Since Co 0100110011 307, then

M 307 • 205 • 307 • 205 • 443 • 307mod527 443 • 392 • 443 • 307 • mod527 69.

Then the protective sequence must be applied on the bill.
M 69 1000101.

 A fragment of a secure bill is shown in FIG. 3.

 To verify the authenticity of the banknote, the client reads the protective sequence M 69, and individual characteristics Co = 307.

Если C=Co, то купюра подлинная.Using the open information of the values N = 527 and e = 7, he calculates C. That is

If C = Co, then the bill is genuine.

 In order for the counterfeiter to forge a bill, he needs to calculate the secret key d = 343 based on the open information N and e.

 Of course, in the given simple example, finding the secret key d is not difficult even by simply sorting through all possible values from zero to N-1.

получим защитный секретный ключ, практически гарантирующий от математического взлома системы защиты.Selecting N over

we get a security secret key that practically guarantees against mathematical hacking of the security system.

 As individual features of the bill, it is necessary to use only those features that cannot be repeated with any existing technological methods.

 Consider now a specific example of protecting dollar bills from counterfeiting.

 1. Application of a security code by a legal issuer.

 1.1. On a bill, we choose a section free of any drawings or texts, for example, the section in FIG. 1, which we will use in the future to calculate the identifier vector.

 1.2. We apply a typographic method in the center of this section to a marker line 1 cm long for positioning this section during authentication, or this section can be created on paper by positioning scanning equipment using mechanical guides.

 1.3 Using an optical scanner, we obtain the first image X (X1.Xn) of size 10 • 10 mm (Fig. 4) and record it in digital form.

 1.4. Using an optical scanner, we obtain the second image Y (Y1. Yn) of the same section as in § 1.3. but with an inclined backlight from above (Fig. 5) and record it in digital form.

 1.5. Using an optical scanner, we obtain the third image Z (Z1. Zn), but with an inclined backlight, it sat down (or to the right) (Fig. 6) and records it in digital form.

 1.6. Subtracting the digital representation of the third image from the second, we obtain the fourth digital image L (L1.Ln).

1.7. Using any of the known redundancy reduction algorithms, the vectors X and L are transformed into vectors X * and L * of significantly smaller dimension N1 and N2 [6]
In practice, close to optimal values are obtained at No 100 • 100, N1 900, N2 250.

1.8. We get the vector C identifier of the protected bill by attaching the sequence X * to L *, i.e.
C = X * | L *
Vector C has dimension N N1 + N2 1150.

.1.9. Using any public key encryption algorithm, or an electronic signature algorithm, the legitimate issuer encrypts the vector C and obtains the ciphertext M, in which the encrypted form contains detailed information about the identifier of the particular protected note [7]
1.10. To reduce the impact on the security code of minor damage to the bill and random errors, the ciphertext M is encoded with a code correcting t errors, as a result, we obtain the security code M *. Depending on the requirements for the degree of protection of the bill from errors, we obtain the dimension M * from 2000 to 10000 and t from 200 to 2000 [5]
1.11. The obtained security code M * is applied typographically by a bill below the marker line. A view of the portion protected in this way by the bill is shown in FIG. 7. Here, the cipher drawing is found for the example of FIG. 4-6 for the BCH code (2300, 1150, 575), correcting t = 287 errors and RSA cipher algorithm with

.

 1.12. Operations 1.2.-1.11. repeated for all protected notes.

 1.13. Information on the method of protection, algorithms for reducing redundancy and encryption (except for the encryption key), error-correcting encoding is openly published and transmitted to interested banks, shops, etc.

 Let us give some explanations to the algorithm for protecting dollar bills.

 Operation 1.1. necessary to reduce the effect on the security code of deterministic signs and errors.

 Operation 1.2. necessary to ensure positioning during scanning and to ensure the correct operation of encryption and decryption.

 This operation can also be carried out by other known methods of positioning a security paper in front of the scanner, for example, mechanical guides.

 Operations 1.3.-1.6. are necessary in order to exclude the possibility of falsification of individual features of the bill even when using the most modern and promising technological methods.

 Operations 1.3. allows you to encrypt a flat microstructure, and operations 1.4.-1.5. volumetric microstructure of the paper base. Moreover, the operation 1.6. allows you to exclude from the image "flat" components.

 Operations 1.3. -1.6. can be replaced by a scanning operation in one plane while reducing the resolution of the scanner to values at which the linear dimensions of the visible inhomogeneities of the paper medium become inaccessible to repeat their exact location in the fake using existing technologies. The choice between these scanning options depends on economic feasibility.

 Operation 1.7. necessary to eliminate redundant information from images, which is necessary to increase the efficiency of the operation encryption algorithm.

 At operation 1.9. the legal issuer must choose the best public key encryption algorithm known to him and credible for him, for example RSA.

 Operation 1.10. necessary to reduce the likelihood of "false alarm" when authenticating banknotes. If the protective sequence obtained in step 1.9. to put on a bill without additional noise-resistant coding, then any, the slightest damage to the bill at the place of application of the security code or a small speck will lead to the inability to decrypt the security code and make a false decision to fake the bill.

 Operations 1.11.-1.13 are necessary to ensure the authenticity of banknotes by all customers.

 2. Authentication of notes.

 2.1. We find the marker line on the bill.

 2.2. Using an optical scanner, we carry out the same operations as in operations 1.3.-1.6 and store the two received images X and L in memory.

 2.3. Using an optical scanner, we read the security code M ** below the marker line (possibly differing from the correct M * code by random t * errors).

2.4. Using the well-known decoding algorithm, we correct t * errors and obtain the security code M [5]
2.5. Using the published information about the encryption algorithm and the decryption key d, we find the identifier C.

2.6. Selecting vectors X * and L * from identifier C, we obtain from them the introduction of redundancy reference images X | and L |
2.7. We calculate the correlation function between X and X |, as well as L and L |.

 2.8. According to the value of the correlation coefficient, clause 2.7. a decision is made on the authenticity of the bill.

 Operations 2.7.-2.8. during verification of banknotes they ensure the invariance of test results to positioning errors, scaling and reduce false alarms due to minor damage to the banknotes in the place from which the image X and L.

 In FIG. 8 is a structural diagram of an embodiment of a device for applying a security code to a bill.

 The device operates as follows.

 Through a mechanical feeder 1 and receiver 2, a correctly oriented bill is fed into the optical scanning unit 3, where operations 1.3-1.5 are implemented. Digital signals from the optical scanning unit are supplied to the digital processing unit 4, where all calculations are performed to implement steps 1.6-1.10. Next, the bill is fed into the printer 5, where the security code is applied to the bill by the signals from the digital processing unit. At the output of block 4, “12” signals are also generated that carry information about the encryption parameters.

In FIG. 9 is a structural diagram of a digital processing unit that operates as follows. Digital signals carrying information about the image X, enters the device 6 reduction of redundancy [6] from the output of which the information enters the device 7 Association. The digital signals corresponding to the image Y and Z are sent to the arithmetic unit 8, where the difference LY Z is calculated. The signals L, through the device 9 for reducing redundancy, are fed to the second input of the combining device 7, the output of which is the signal C = X * | L *
From the output of the combining device 7, the signal C goes to the input of the two-key encryption block 10 [7] where the signal C is converted using the private key d into the ciphertext M. The encryption parameters are calculated in block 11 and fed to the encryption block 10 and to the output of the device 12. Ciphertext M from the output of block 10, it enters block 13 of error-correcting coding [5] where, by introducing redundancy, the noise-resistant security code M is calculated, which is output to the device 14.

 In FIG. 10 is a structural diagram of a bill validator.

 The device operates as follows.

 Correctly oriented bill through the mechanical positioning device 15 enters the optical scanning unit 16, where actions are performed for the implementation of operations 2.1-2.3. The digital signal is supplied to the digital processing unit 17, where all calculations are performed for the implementation of operations 2.4.-2.8.

 The result of digital processing is fed to the display unit 18.

 The cost of protecting the price of paper with the proposed method is determined as follows.

The cost of equipment for the protection of securities is:
a) a mechanical receiver of about 2 thousand US dollars;
b) an optical scanning unit of about 20 thousand US dollars;
c) a digital processing unit of about 50 thousand US dollars;
d) a printer of about 5 thousand US dollars;
In total, taking into account additional costs, not more than 200 thousand US dollars.

Если оборудование для защиты документов будет обслуживаться круглосуточно персоналом из двух человек (всего 6 человек), с заработной платой 50 тыс. долларов США в год на каждого, (общий фонд оплаты труда с учетом налогов 600 тыс. долларов в год, 3 млн. долларов за 5 лет), с учетом дополнительных расходов, равных фонду оплаты труда (аренда, накладные расходы и т. п.), получим себестоимость защиты одной ценой бумаги

Надежность защиты купюры от подделки гарантируется невозможностью подделать микроструктуру бумаги и вычислить ключ защиты при достаточно большом N.The proposed equipment should provide round-the-clock operation for five years. At a productivity of no worse than one document in 5 seconds, until the equipment is completely worn out, taking into account a continuity coefficient of 0.9, no less than

If the equipment for the protection of documents will be serviced around the clock by two-person personnel (total 6 people), with a salary of 50 thousand US dollars per year for each, (total payroll including taxes 600 thousand dollars per year, 3 million dollars for 5 years), taking into account additional costs equal to the wage fund (rent, overhead costs, etc.), we get the cost of protection for one price of paper

Reliability of protection of the bill against counterfeiting is guaranteed by the inability to forge the microstructure of the paper and calculate the security key with a sufficiently large N.

 The author made an industrial design of a device for protecting securities from counterfeiting and a device for controlling the authenticity of securities.

 Tests of the device confirmed their operability and the inability to forge a document protected by the claimed method.

Claims (4)

 1. A method of protecting securities from counterfeiting, which consists in applying marks corresponding to the identification code in a given area of a security, characterized in that the microstructure of each protected security is electronically scanned, and the values of the identifier vector parameters corresponding to this microstructure are generated from the scanning results, transform the identifier vector by means of error-correcting coding into a security code, the values of which correspond to the labels of the identification code, are located in a predetermined area of the security.  2. The method according to p. 1, characterized in that the scanning microstructure of the security is performed in two intersecting planes.  3. The method according to p. 1, characterized in that the scanning microstructure of the security is performed in the visible region of the spectrum by optoelectronic conversion.  4. The method according to p. 1, characterized in that before applying the security code it is converted into another code by error-correcting coding.

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